PIC16C773
PIC16C773
PIC16C773
PIC16C77X
28/40-Pin, 8-Bit CMOS Microcontrollers w/ 12-Bit A/D
Microcontroller Core Features: Pin Diagram
High-performance RISC CPU
Only 35 single word instructions to learn 600 mil. PDIP, Windowed CERDIP
All single cycle instructions except for program
MCLR/VPP 1 40 RB7
branches which are two cycle RA0/AN0 2 39 RB6
RA1/AN1 3 38 RB5
Operating speed: DC - 20 MHz clock input RA2/AN2/VREF-/VRL 4 37 RB4
RA3/AN3/VREF+/VRH RB3/AN9/LVDIN
DC - 200 ns instruction cycle RA4/T0CKI
5
6
36
35 RB2/AN8
PIC16C774
4K x 14 words of Program Memory, RA5/AN4
RE0/RD/AN5
7
8
34
33
RB1/SS
RB0/INT
256 x 8 bytes of Data Memory (RAM) RE1/WR/AN6 9 32 VDD
RE2/CS/AN7 10 31 VSS
Interrupt capability (up to 14 internal/external AVDD 11 30 RD7/PSP7
AVSS 12 29 RD6/PSP6
interrupt sources) OSC1/CLKIN 13 28 RD5/PSP5
OSC2/CLKOUT 14 27 RD4/PSP4
Eight level deep hardware stack RC0/T1OSO/T1CKI 15 26 RC7/RX/DT
RC1/T1OSI/CCP2 16 25 RC6/TX/CK
Direct, indirect, and relative addressing modes RC2/CCP1 17 24 RC5/SDO
RC3/SCK/SCL 18 23 RC4/SDI/SDA
Power-on Reset (POR) RD0/PSP0 19 22 RD3/PSP3
RD1/PSP1 20 21 RD2/PSP2
Power-up Timer (PWRT) and
Oscillator Start-up Timer (OST)
Watchdog Timer (WDT) with its own on-chip RC Peripheral Features:
oscillator for reliable operation
Timer0: 8-bit timer/counter with 8-bit prescaler
Programmable code-protection
Timer1: 16-bit timer/counter with prescaler,
Power saving SLEEP mode can be incremented during sleep via external
Selectable oscillator options crystal/clock
Low-power, high-speed CMOS EPROM Timer2: 8-bit timer/counter with 8-bit period
technology register, prescaler and postscaler
Fully static design Two Capture, Compare, PWM modules
In-Circuit Serial Programming(ISCP Capture is 16-bit, max. resolution is 12.5 ns,
Wide operating voltage range: 2.5V to 5.5V Compare is 16-bit, max. resolution is 200 ns,
High Sink/Source Current 25/25 mA PWM max. resolution is 10-bit
12-bit multi-channel Analog-to-Digital converter
Commercial and Industrial temperature ranges * On-chip absolute bandgap voltage reference
Low-power consumption:
- < 2 mA @ 5V, 4 MHz
* generator
Synchronous Serial Port (SSP) with SPI (Master
- 22.5 A typical @ 3V, 32 kHz * Mode) and I2C
- < 1 A typical standby current
Universal Synchronous Asynchronous Receiver
* Transmitter, supports high/low speeds and 9-bit
address mode (USART/SCI)
Parallel Slave Port (PSP) 8-bits wide, with
external RD, WR and CS controls
Programmable Brown-out detection circuitry for
* Brown-out Reset (BOR)
* Enhanced features Programmable Low-voltage detection circuitry
*
PIC16C77X
Pin Diagrams
MCLR/VPP 1 28 RB7
RA0/AN0 2 27 RB6
RA1/AN1 3 26 RB5
RA2/AN2/VREF-/VRL 4 25 RB4
PIC16C773
RA3/AN3/VREF+/VRH 5 24 RB3/AN9/LVDIN
RA4/T0CKI 6 23 RB2/AN8
AV DD 7 22 RB1/SS
AVSS 8 21 RB0/INT
OSC1/CLKIN 9 20 VDD
OSC2/CLKOUT 10 19 VSS
RC0/T1OSO/T1CKI 11 18 RC7/RX/DT
RC1/T1OSI/CCP2 12 17 RC6/TX/CK
RC2/CCP1 13 16 RC5/SDO
RC3/SCK/SCL 14 15 RC4/SDI/SDA
RA3/AN3/VREF+/VRH
RA2/AN2/VREF-/VRL
MCLR/VPP
RA1/AN1
RA0/AN0
PLCC
RB7
RB6
RB5
RB4
NC
NC
44
43
42
41
40
6
5
4
3
2
1
RA4/T0CKI 7 39 RB3/AN9/LVDIN
RA5/AN4 8 38 RB2/AN8
RE0/RD/AN5 9 37 RB1/SS
RE1/WR/AN6 10 36 RB0/INT
RE2/CS/AN7 11 35 VDD
AVDD 12
PIC16C774 34 VSS
AVSS 13 33 RD7/PSP7
OSC1/CLKIN 14 32 RD6/PSP6
OSC2/CLKOUT 15 31 RD5/PSP5
RC0/T1OSO/T1CKI 16 30 RD4/PSP4
NC 17 29 RC7/RX/DT
18
19
20
21
22
23
24
25
26
27
28
RD2/PSP2
RD3/PSP3
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RD0/PSP0
RD1/PSP1
NC
RC5/SDO
RC4/SDI/SDA
RC6/TX/CK
RC1/T1OSI/CCP2
RC3/SCK/SCL
RC4/SDI/SDA
RC6/TX/CK
RC2/CCP1
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC5/SDO
MQFP
NC
TQFP
44
43
42
41
40
39
38
37
36
35
34
RC7/RX/DT 1 33 NC
RD4/PSP4 2 32 RC0/T1OSO/T1CKI
RD5/PSP5 3 31 OSC2/CLKOUT
RD6/PSP6 4 30 OSC1/CLKIN
RD7/PSP7 5 29 AVSS
VSS 6 28 AVDD
VDD 7 PIC16C774 27 RE2/CS/AN7
RB0/INT 8 26 RE1/WR/AN6
RB1/SS 9 25 RE0/RD/AN5
RB2/AN8 10 24 RA5/AN4
RB3/AN9/LVDIN 11 23 RA4/T0CKI
12
13
14
15
16
17
18
19
20
21
22
RA2/AN2/VREF-/VRL
RA3/AN3/VREF+/VRH
RB4
RB5
RB6
RB7
RA0/AN0
RA1/AN1
NC
NC
MCLR/VPP
PIC16C77X
Key Features
PICmicro Mid-Range Reference Manual PIC16C773 PIC16C774
(DS33023)
Operating Frequency DC - 20 MHz DC - 20 MHz
Resets (and Delays) POR, BOR, MCLR, WDT POR, BOR, MCLR, WDT
(PWRT, OST) (PWRT, OST)
Program Memory (14-bit words) 4K 4K
Data Memory (bytes) 256 256
Interrupts 13 14
I/O Ports Ports A,B,C Ports A,B,C,D,E
Timers 3 3
Capture/Compare/PWM modules 2 2
Serial Communications MSSP, USART MSSP, USART
Parallel Communications PSP
12-bit Analog-to-Digital Module 6 input channels 10 input channels
Instruction Set 35 Instructions 35 Instructions
PIC16C77X
Table of Contents
1.0 Device Overview ............................................................................................................................................................................ 5
2.0 Memory Organization................................................................................................................................................................... 11
3.0 I/O Ports ....................................................................................................................................................................................... 27
4.0 Timer0 Module ............................................................................................................................................................................. 39
5.0 Timer1 Module ............................................................................................................................................................................. 41
6.0 Timer2 Module ............................................................................................................................................................................. 45
7.0 Capture/Compare/PWM (CCP) Module(s)................................................................................................................................... 47
8.0 Master Synchronous Serial Port (MSSP) Module ........................................................................................................................ 53
9.0 Addressable Universal Synchronous Asynchronous Receiver Transmitter (USART) ................................................................. 97
10.0 Voltage Reference Module and Low-voltage Detect.................................................................................................................. 113
11.0 Analog-to-Digital Converter (A/D) Module ................................................................................................................................. 117
12.0 Special Features of the CPU ..................................................................................................................................................... 127
13.0 Instruction Set Summary............................................................................................................................................................ 143
14.0 Development Support ................................................................................................................................................................ 145
15.0 Electrical Characteristics............................................................................................................................................................ 151
16.0 DC and AC Characteristics Graphs and Tables ........................................................................................................................ 173
17.0 Packaging Information ............................................................................................................................................................... 175
Appendix A: Revision History ......................................................................................................................................................... 187
Appendix B: Device Differences..................................................................................................................................................... 187
Appendix C: Conversion Considerations........................................................................................................................................ 187
Index .................................................................................................................................................................................................. 189
Bit/Register Cross-Reference List...................................................................................................................................................... 196
On-Line Support................................................................................................................................................................................. 197
Reader Response .............................................................................................................................................................................. 198
PIC16C77X Product Identification System......................................................................................................................................... 199
PIC16C77X
1.0 DEVICE OVERVIEW There a two devices (PIC16C773 and PIC16C774)
covered by this datasheet. The PIC16C773 devices
This document contains device-specific information. come in 28-pin packages and the PIC16C774 devices
Additional information may be found in the PICmicro come in 40-pin packages. The 28-pin devices do not
Mid-Range Reference Manual, (DS33023), which may have a Parallel Slave Port implemented.
be obtained from your local Microchip Sales Represen-
tative or downloaded from the Microchip website. The The following two figures are device block diagrams
Reference Manual should be considered a comple- sorted by pin number; 28-pin for Figure 1-1 and 40-pin
mentary document to this data sheet, and is highly rec- for Figure 1-2. The 28-pin and 40-pin pinouts are listed
ommended reading for a better understanding of the in Table 1-1 and Table 1-2, respectively.
device architecture and operation of the peripheral
modules.
FIGURE 1-1: PIC16C773 BLOCK DIAGRAM
13 Data Bus 8 PORTA
Program Counter
EPROM RA0/AN0
Program RA1/AN1
Memory RA2/AN2/VREF-/VRL
RAM
8 Level Stack RA3/AN3/VREF+/VRH
4K x 14 File RA4/T0CKI
(13-bit) Registers
256 x 8
Program 14
Bus RAM Addr (1) 9 PORTB
Addr MUX RB0/INT
Instruction reg RB1/SS
7 Indirect RB2/AN8
Direct Addr
8 Addr RB3/AN9/LVDIN
RB7:RB4
FSR reg
STATUS reg
8 PORTC
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
3 RC2/CCP1
MUX
Instruction RC3/SCK/SCL
Decode & RC4/SDI/SDA
Control Power-up
Timer RC5/SDO
ALU RC6/TX/CK
Timing Oscillator RC7/RX/DT
OSC1/CLKIN Generation Start-up Timer 8
OSC2/CLKOUT
Power-on
Reset W reg
Watchdog
Timer
Low-voltage Precision Brown-out
Detect Reference Reset
12-bit AVDD
ADC AVSS
Synchronous
CCP1,2 USART
Serial Port
PIC16C77X
FIGURE 1-2: PIC16C774 BLOCK DIAGRAM
13 Data Bus 8 PORTA
Program Counter
EPROM RA0/AN0
Program RA1/AN1
Memory RA2/AN2/VREF-/VRL
RAM
8 Level Stack RA3/AN3/VREF+/VRH
4K x 14 File
(13-bit) Registers RA4/T0CKI
RA5/AN4
256 x 8
Program 14
Bus RAM Addr (1) 9 PORTB
Addr MUX RB0/INT
Instruction reg RB1/SS
7 Indirect RB2/AN8
Direct Addr
8 Addr RB3/AN9/LVDIN
FSR reg RB7:RB4
STATUS reg
8 PORTC
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
3 RC2/CCP1
MUX
Instruction RC3/SCK/SCL
Decode & RC4/SDI/SDA
Control Power-up
Timer RC5/SDO
ALU RC6/TX/CK
Timing Oscillator RC7/RX/DT
OSC1/CLKIN Generation Start-up Timer 8
OSC2/CLKOUT PORTD
Power-on
Reset W reg
Watchdog
Timer RD7/PSP7:RD0/PSP0
Low-voltage Precision Brown-out
Detect Reference Reset
RE0/AN5/RD
MCLR VDD, VSS
RE1/AN6/WR
12-bit AV DD RE2/AN7/CS
ADC
AVSS
Synchronous
CCP1,2 USART
Serial Port
PIC16C77X
TABLE 1-1 PIC16C773 PINOUT DESCRIPTION
DIP,
SSOP, I/O/P Buffer
Pin Name Description
SOIC Type Type
Pin#
PIC16C77X
TABLE 1-2 PIC16C774 PINOUT DESCRIPTION
DIP PLCC QFP I/O/P Buffer
Pin Name Description
Pin# Pin# Pin# Type Type
(4)
OSC1/CLKIN 13 14 30 I ST/CMOS Oscillator crystal input/external clock source input.
OSC2/CLKOUT 14 15 31 O Oscillator crystal output. Connects to crystal or resonator
in crystal oscillator mode. In RC mode, OSC2 pin outputs
CLKOUT which has 1/4 the frequency of OSC1, and
denotes the instruction cycle rate.
MCLR/VPP 1 2 18 I/P ST Master clear (reset) input or programming voltage input.
This pin is an active low reset to the device.
PORTA is a bi-directional I/O port.
RA0/AN0 2 3 19 I/O TTL RA0 can also be analog input0
RA1/AN1 3 4 20 I/O TTL RA1 can also be analog input1
RA2/AN2/VREF-/VRL 4 5 21 I/O TTL RA2 can also be analog input2 or negative analog
reference voltage input or internal voltage reference
low
RA3/AN3/VREF+/VRH 5 6 22 I/O TTL RA3 can also be analog input3 or positive analog
reference voltage input or internal voltage reference
high
RA4/T0CKI 6 7 23 I/O ST RA4 can also be the clock input to the Timer0 timer/
counter. Output is open drain type.
RA5/AN4 7 8 24 I/O TTL RA5 can also be analog input4
PORTB is a bi-directional I/O port. PORTB can be soft-
ware programmed for internal weak pull-up on all inputs.
RB0/INT 33 36 8 I/O TTL/ST(1) RB0 can also be the external interrupt pin.
RB1/SS 34 37 9 I/O TTL/ST(1) RB1 can also be the SSP slave select
RB2/AN8 35 38 10 I/O TTL RB2 can also be analog input8
RB3/AN9/LVDIN 36 39 11 I/O TTL RB3 can also be analog input9 or input reference for
low voltage detect
RB4 37 41 14 I/O TTL Interrupt on change pin.
RB5 38 42 15 I/O TTL Interrupt on change pin.
RB6 39 43 16 I/O TTL/ST(2) Interrupt on change pin. Serial programming clock.
RB7 40 44 17 I/O TTL/ST(2) Interrupt on change pin. Serial programming data.
Legend: I = input O = output I/O = input/output P = power
= Not used TTL = TTL input ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured for the multiplexed function.
2: This buffer is a Schmitt Trigger input when used in serial programming mode.
3: This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel
Slave Port mode (for interfacing to a microprocessor bus).
4: This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise.
PIC16C77X
TABLE 1-2 PIC16C774 PINOUT DESCRIPTION (Cont.d)
DIP PLCC QFP I/O/P Buffer
Pin Name Description
Pin# Pin# Pin# Type Type
PIC16C77X
NOTES:
PIC16C77X
2.0 MEMORY ORGANIZATION 2.2 Data Memory Organization
There are two memory blocks in each of these The data memory is partitioned into multiple banks
PICmicro microcontrollers. Each block (Pro- which contain the General Purpose Registers and the
gram Memory and Data Memory) has its own bus Special Function Registers. Bits RP1 and RP0 are the
so that concurrent access can occur. bank select bits.
Additional information on device memory may be found RP1 RP0 (STATUS<6:5>)
in the PICmicro Mid-Range Reference Manual,
(DS33023). = 00 Bank0
= 01 Bank1
2.1 Program Memory Organization = 10 Bank2
= 11 Bank3
The PIC16C77X PICmicros have a 13-bit program
counter capable of addressing an 8K x 14 program Each bank extends up to 7Fh (128 bytes). The lower
memory space. Each device has 4K x 14 words of pro- locations of each bank are reserved for the Special
gram memory. Accessing a location above the physi- Function Registers. Above the Special Function Regis-
cally implemented address will cause a wraparound. ters are General Purpose Registers, implemented as
static RAM. All implemented banks contain special
The reset vector is at 0000h and the interrupt vector is function registers. Some high use special function
at 0004h. registers from one bank may be mirrored in another
bank for code reduction and quicker access.
FIGURE 2-1: PROGRAM MEMORY MAP
AND STACK 2.2.1 GENERAL PURPOSE REGISTER FILE
CALL, RETURN 13
RETFIE, RETLW
Stack Level 1
Stack Level 2
Stack Level 8
3FFFh
PIC16C77X
FIGURE 2-2: REGISTER FILE MAP
PIC16C77X
2.2.2 SPECIAL FUNCTION REGISTERS The special function registers can be classified into two
sets; core (CPU) and peripheral. Those registers asso-
The Special Function Registers are registers used by ciated with the core functions are described in detail in
the CPU and Peripheral Modules for controlling the this section. Those related to the operation of the
desired operation of the device. These registers are peripheral features are described in detail in that
implemented as static RAM. A list of these registers is peripheral feature section.
given in Table 2-1.
Bank 0
00h(4) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 0000 0000
02h(4) PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000
04h(4) FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu
05h PORTA PORTA5(5) PORTA Data Latch when written: PORTA<4:0> pins when read --0x 0000 --0u 0000
06h PORTB PORTB Data Latch when written: PORTB pins when read xxxx 11xx uuuu 11uu
07h PORTC PORTC Data Latch when written: PORTC pins when read xxxx xxxx uuuu uuuu
08h(5) PORTD PORTD Data Latch when written: PORTD pins when read xxxx xxxx uuuu uuuu
0Ah(1,4) PCLATH Write Buffer for the upper 5 bits of the Program Counter ---0 0000 ---0 0000
0Bh(4) INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
0Ch PIR1 PSPIF(3) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
0Eh TMR1L Holding register for the Least Significant Byte of the 16-bit TMR1 register xxxx xxxx uuuu uuuu
0Fh TMR1H Holding register for the Most Significant Byte of the 16-bit TMR1 register xxxx xxxx uuuu uuuu
10h T1CON T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 --uu uuuu
12h T2CON TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
13h SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu
14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000
17h CCP1CON CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
18h RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
19h TXREG USART Transmit Data Register 0000 0000 0000 0000
1Ah RCREG USART Receive Data Register 0000 0000 0000 0000
1Dh CCP2CON CCP2X CCP2Y CCP2M3 CCP2M2 CCP2M1 CCP2M0 --00 0000 --00 0000
1Eh ADRESH A/D High Byte Result Register xxxx xxxx uuuu uuuu
1Fh ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE CHS3 ADON 0000 0000 0000 0000
PIC16C77X
TABLE 2-1 PIC16C77X SPECIAL FUNCTION REGISTER SUMMARY (Cont.d)
Value on: Value on all
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR, other resets
BOR (2)
Bank 1
80h(4) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 0000 0000
81h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
82h(4) PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000
84h(4) FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu
85h TRISA bit5(5) PORTA Data Direction Register --11 1111 --11 1111
86h TRISB PORTB Data Direction Register 1111 1111 1111 1111
87h TRISC PORTC Data Direction Register 1111 1111 1111 1111
88h(5) TRISD PORTD Data Direction Register 1111 1111 1111 1111
89h(5) TRISE IBF OBF IBOV PSPMODE PORTE Data Direction Bits 0000 -111 0000 -111
8Ah(1,4) PCLATH Write Buffer for the upper 5 bits of the Program Counter ---0 0000 ---0 0000
8Bh(4) INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
8Ch PIE1 PSPIE(3) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
8Fh Unimplemented
90h Unimplemented
91h SSPCON2 GCEN AKSTAT AKDT AKEN RCEN PEN RSEN SEN 0000 0000 0000 0000
93h SSPADD Synchronous Serial Port (I2C mode) Address Register 0000 0000 0000 0000
94h SSPSTAT SMP CKE D/A P S R/W UA BF 0000 0000 0000 0000
95h Unimplemented
96h Unimplemented
97h Unimplemented
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 0000 -010
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
9Ah Unimplemented
9Bh REFCON VRHEN VRLEN VRHOEN VRLOEN 0000 ---- 0000 ----
9Ch LVDCON BGST LVDEN LV3 LV2 LV1 LV0 --00 0101 --00 0101
9Ah Unimplemented
9Eh ADRESL A/D Low Byte Result Register xxxx xxxx uuuu uuuu
9Fh ADCON1 ADFM VCFG2 VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0 0000 0000 0000 0000
PIC16C77X
TABLE 2-1 PIC16C77X SPECIAL FUNCTION REGISTER SUMMARY (Cont.d)
Value on: Value on all
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR, other resets
BOR (2)
Bank 2
100h(4) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 0000 0000
102h(4) PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000
104h(4) FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu
105h Unimplemented
106h PORTB PORTB Data Latch when written: PORTB pins when read xxxx 11xx uuuu 11uu
107h Unimplemented
108h Unimplemented
109h Unimplemented
10Ah(1,4) PCLATH Write Buffer for the upper 5 bits of the Program Counter ---0 0000 ---0 0000
10Bh(4) INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
10Ch-
Unimplemented
10Fh
Bank 3
180h(4) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 0000 0000
181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
182h(4) PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000
184h(4) FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu
185h Unimplemented
186h TRISB PORTB Data Direction Register 1111 1111 1111 1111
187h Unimplemented
188h Unimplemented
189h Unimplemented
18Ah(1,4) PCLATH Write Buffer for the upper 5 bits of the Program Counter ---0 0000 ---0 0000
18Bh(4) INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
18Ch-
Unimplemented
18Fh
PIC16C77X
2.2.2.1 STATUS REGISTER For example, CLRF STATUS will clear the upper-three
bits and set the Z bit. This leaves the STATUS register
The STATUS register, shown in Figure 2-3, contains as 000u u1uu (where u = unchanged).
the arithmetic status of the ALU, the RESET status and
the bank select bits for data memory. It is recommended, therefore, that only BCF, BSF,
SWAPF and MOVWF instructions are used to alter the
The STATUS register can be the destination for any STATUS register because these instructions do not
instruction, as with any other register. If the STATUS affect the Z, C or DC bits from the STATUS register. For
register is the destination for an instruction that affects other instructions, not affecting any status bits, see the
the Z, DC or C bits, then the write to these three bits is "Instruction Set Summary."
disabled. These bits are set or cleared according to the
device logic. Furthermore, the TO and PD bits are not Note 1: The C and DC bits operate as a borrow and
writable. Therefore, the result of an instruction with the digit borrow bit, respectively, in subtraction.
STATUS register as destination may be different than See the SUBLW and SUBWF instructions for
intended. examples.
PIC16C77X
2.2.2.2 OPTION_REG REGISTER
Note: To achieve a 1:1 prescaler assignment for
The OPTION_REG register is a readable and writable the TMR0 register, assign the prescaler to
register which contains various control bits to configure the Watchdog Timer.
the TMR0 prescaler/WDT postscaler (single assign-
able register known also as the prescaler), the External
INT Interrupt, TMR0, and the weak pull-ups on PORTB.
PIC16C77X
2.2.2.3 INTCON REGISTER
Note: Interrupt flag bits get set when an interrupt
The INTCON Register is a readable and writable regis- condition occurs regardless of the state of
ter which contains various enable and flag bits for the its corresponding enable bit or the global
TMR0 register overflow, RB Port change and External enable bit, GIE (INTCON<7>). User soft-
RB0/INT pin interrupts. ware should ensure the appropriate inter-
rupt flag bits are clear prior to enabling an
interrupt.
PIC16C77X
2.2.2.4 PIE1 REGISTER Note: Bit PEIE (INTCON<6>) must be set to
This register contains the individual enable bits for the enable any peripheral interrupt.
peripheral interrupts.
Note 1: PSPIE is reserved on the 28-pin devices, always maintain this bit clear.
PIC16C77X
2.2.2.5 PIR1 REGISTER
Note: Interrupt flag bits get set when an interrupt
This register contains the individual flag bits for the condition occurs regardless of the state of
peripheral interrupts. its corresponding enable bit or the global
enable bit, GIE (INTCON<7>). User soft-
ware should ensure the appropriate inter-
rupt flag bits are clear prior to enabling an
interrupt.
Note 1: PSPIF is reserved on the 28-pin devices, always maintain this bit clear.
PIC16C77X
2.2.2.6 PIE2 REGISTER
PIC16C77X
2.2.2.7 PIR2 REGISTER .
Note: Interrupt flag bits get set when an interrupt
This register contains the CCP2, SSP Bus Collision, condition occurs regardless of the state of
and Low-voltage detect interrupt flag bits. its corresponding enable bit or the global
enable bit, GIE (INTCON<7>). User soft-
ware should ensure the appropriate inter-
rupt flag bits are clear prior to enabling an
interrupt.
Capture Mode
1 = A TMR1 register capture occurred (must be cleared in software)
0 = No TMR1 register capture occurred
Compare Mode
1 = A TMR1 register compare match occurred (must be cleared in software)
0 = No TMR1 register compare match occurred
PWM Mode
Unused
PIC16C77X
2.2.2.8 PCON REGISTER Note: BOR is unknown on Power-on Reset. It
The Power Control (PCON) register contains a flag bit must then be set by the user and checked
to allow differentiation between a Power-on Reset on subsequent resets to see if BOR is
(POR) to an external MCLR Reset or WDT Reset. clear, indicating a brown-out has occurred.
Those devices with brown-out detection circuitry con- The BOR status bit is a don't care and is
tain an additional bit to differentiate a Brown-out Reset not necessarily predictable if the brown-out
condition from a Power-on Reset condition. circuit is disabled (by clearing the BODEN
bit in the Configuration word).
PIC16C77X
2.3 PCL and PCLATH 2.4 Program Memory Paging
The program counter (PC) specifies the address of the PIC16C77X devices are capable of addressing a con-
instruction to fetch for execution. The PC is 13 bits tinuous 8K word block of program memory. The CALL
wide. The low byte is called the PCL register. This reg- and GOTO instructions provide only 11 bits of address
ister is readable and writable. The high byte is called to allow branching within any 2K program memory
the PCH register. This register contains the PC<12:8> page. When doing a CALL or GOTO instruction the
bits and is not directly readable or writable. All updates upper 2 bits of the address are provided by
to the PCH register go through the PCLATH register. PCLATH<4:3>. When doing a CALL or GOTO instruc-
tion, the user must ensure that the page select bits are
2.3.1 STACK programmed so that the desired program memory
page is addressed. If a return from a CALL instruction
The stack allows a combination of up to 8 program calls
(or interrupt) is executed, the entire 13-bit PC is pushed
and interrupts to occur. The stack contains the return
onto the stack. Therefore, manipulation of the
address from this branch in program execution.
PCLATH<4:3> bits are not required for the return
Midrange devices have an 8 level deep x 13-bit wide instructions (which POPs the address from the stack).
hardware stack. The stack space is not part of either
program or data space and the stack pointer is not
readable or writable. The PC is PUSHed onto the stack
when a CALL instruction is executed or an interrupt
causes a branch. The stack is POPed in the event of a
RETURN, RETLW or a RETFIE instruction execution.
PCLATH is not modified when the stack is PUSHed or
POPed.
After the stack has been PUSHed eight times, the ninth
push overwrites the value that was stored from the first
push. The tenth push overwrites the second push (and
so on).
PIC16C77X
The INDF register is not a physical register. Address- EXAMPLE 2-1: HOW TO CLEAR RAM
ing INDF actually addresses the register whose USING INDIRECT
address is contained in the FSR register (FSR is a ADDRESSING
pointer). This is indirect addressing.
movlw 0x20 ;initialize pointer
Reading INDF itself indirectly (FSR = 0) will produce movwf FSR ; to RAM
00h. Writing to the INDF register indirectly results in a NEXT clrf INDF ;clear INDF register
no-operation (although STATUS bits may be affected). incf FSR ;inc pointer
A simple program to clear RAM locations 20h-2Fh btfss FSR,4 ;all done?
goto NEXT ;NO, clear next
using indirect addressing is shown in Example 2-1.
CONTINUE
: ;YES, continue
An effective 9-bit address is obtained by concatenating
the 8-bit FSR register and the IRP bit (STATUS<7>), as
shown in Figure 2-11.
Data
Memory(1)
PIC16C77X
NOTES:
PIC16C77X
3.0 I/O PORTS FIGURE 3-1: BLOCK DIAGRAM OF
RA3:RA2 PINS
Some pins for these I/O ports are multiplexed with an
alternate function for the peripheral features on the Data
device. In general, when a peripheral is enabled, that bus
D Q
pin may not be used as a general purpose I/O pin.
VDD
Additional information on I/O ports may be found in the WR
Port
PICmicro Mid-Range Reference Manual, CK Q
P
(DS33023).
Data Latch
3.1 PORTA and the TRISA Register N I/O pin(1)
D Q
PORTA is a 6-bit wide bi-directional port for the 40/44
WR
pin devices and is 5-bits wide for the 28-pin devices. TRIS
CK Q VSS
PORTA<5> is not on the 28-pin devices. The corre- Analog
sponding data direction register is TRISA. Setting a input
TRIS Latch mode
TRISA bit (=1) will make the corresponding PORTA pin
an input, i.e., put the corresponding output driver in a
hi-impedance mode. Clearing a TRISA bit (=0) will
make the corresponding PORTA pin an output, i.e., put RD TRIS TTL
input
the contents of the output latch on the selected pin. buffer
Q D
Reading the PORTA register reads the status of the
pins whereas writing to it will write to the port latch. All
write operations are read-modify-write operations.
EN
Therefore a write to a port implies that the port pins are
read, this value is modified, and then written to the port
data latch. RD PORT
PIC16C77X
FIGURE 3-2: BLOCK DIAGRAM OF FIGURE 3-3: BLOCK DIAGRAM OF
RA1:RA0 AND RA5 PINS RA4/T0CKI PIN
Data Data
bus bus D Q
D Q
WR
VDD PORT
WR CK Q
I/O pin(1)
Port N
CK Q Data Latch
P
D Q VSS
Data Latch
WR
D Q N I/O pin(1) TRIS Schmitt
CK Q
Trigger
WR input
TRIS Latch
TRIS buffer
CK Q VSS
Analog
input
TRIS Latch mode RD TRIS
Q D
RD TRIS TTL
input ENEN
buffer
Q D RD PORT
To A/D Converter
05h PORTA(1) RA5 RA4 RA3 RA2 RA1 RA0 --0x 0000 --0u 0000
85h TRISA(1) PORTA Data Direction Register --11 1111 --11 1111
9Fh ADCON1 ADFM VCFG2 VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0 0000 0000 0000 0000
Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. Shaded cells are not used by PORTA.
Note 1: PORTA<5>, TRISA<5> are reserved on the 28-pin devices, maintain these bits clear.
PIC16C77X
3.2 PORTB and the TRISB Register The RB1 pin is multiplexed with the SSP module slave
select (RB1/SS).
PORTB is an 8-bit wide bi-directional port. The corre-
sponding data direction register is TRISB. Setting a FIGURE 3-5: BLOCK DIAGRAM OF RB1/SS
TRISB bit (=1) will make the corresponding PORTB pin
PIN
an input, i.e., put the corresponding output driver in a VDD
hi-impedance mode. Clearing a TRISB bit (=0) will RBPU(2) weak
make the corresponding PORTB pin an output, i.e., put P pull-up
the contents of the output latch on the selected pin. Data Latch
Data bus
D Q
EXAMPLE 3-1: INITIALIZING PORTB WR Port I/O
BCF STATUS, RP0 ; CK pin(1)
CLRF PORTB ; Initialize PORTB by TRIS Latch
; clearing output D Q
TTL
; data latches Input
BSF STATUS, RP0 ; Select Bank 1 WR TRIS
CK Buffer
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISB ; Set RB<3:0> as inputs RD TRIS
; RB<5:4> as outputs Q D
; RB<7:6> as inputs
Each of the PORTB pins has a weak internal pull-up. A RD Port EN
single control bit can turn on all the pull-ups. This is per-
formed by clearing bit RBPU (OPTION_REG<7>). The SS input
weak pull-up is automatically turned off when the port
Schmitt Trigger RD Port
pin is configured as an output. The pull-ups are dis- Buffer
abled on a Power-on Reset. Note 1: I/O pins have diode protection to VDD and VSS.
The RB0 pin is multiplexed with the external interrupt 2: To enable weak pull-ups, set the appropriate TRIS bit(s)
and clear the RBPU bit (OPTION_REG<7>).
(RB0/INT).
The RB2 pin is multiplexed with analog channel 8
FIGURE 3-4: BLOCK DIAGRAM OF RB0 PIN (RB2/AN8).
VDD
RBPU(2) weak FIGURE 3-6: BLOCK DIAGRAM OF
P pull-up
RB2/AN8 PIN
Data Latch
Data bus VDD
D Q
RBPU(2) weak
I/O P pull-up
WR Port
CK pin(1) Data Latch
Data bus
TRIS Latch D Q
D Q
TTL WR Port I/O
Input CK pin(1)
WR TRIS
CK Buffer
TRIS Latch
D Q
Analog
WR TRIS
CK input mode
RD TRIS
Q D TTL
Input
Buffer
RD Port EN RD TRIS
Q D
RB0/INT
RD Port EN
Schmitt Trigger RD Port
Buffer
Note 1: I/O pins have diode protection to VDD and VSS. To A/D converter
2: To enable weak pull-ups, set the appropriate TRIS bit(s)
and clear the RBPU bit (OPTION_REG<7>). RD Port
PIC16C77X
The RB3 pin is multiplexed with analog channel 9 and Four of PORTBs pins, RB7:RB4, have an interrupt on
the low voltage detect input (RB3/AN9/LVDIN) change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e. any RB7:RB4 pin con-
FIGURE 3-7: BLOCK DIAGRAM OF figured as an output is excluded from the interrupt on
RB3/AN9/LVDIN PIN change comparison). The input pins (of RB7:RB4) are
VDD compared with the old value latched on the last read of
RBPU(2) PORTB. The mismatch outputs of RB7:RB4 are
weak
P pull-up ORed together to generate the RB Port Change Inter-
Data bus
Data Latch rupt with flag bit RBIF (INTCON<0>).
D Q
This interrupt can wake the device from SLEEP. The
WR Port I/O user, in the interrupt service routine, can clear the inter-
CK pin(1)
rupt in the following manner:
TRIS Latch
D Q a) Any read or write of PORTB. This will end the
Analog mismatch condition.
WR TRIS
CK input mode b) Clear flag bit RBIF.
or LVD input
mode TTL A mismatch condition will continue to set flag bit RBIF.
Input
Buffer Reading PORTB will end the mismatch condition, and
RD TRIS allow flag bit RBIF to be cleared.
Q D
The interrupt on change feature is recommended for
wake-up on key depression operation and operations
RD Port EN
where PORTB is only used for the interrupt on change
feature. Polling of PORTB is not recommended while
To A/D converter and LVD reference input using the interrupt on change feature.
RD Port
FIGURE 3-8: BLOCK DIAGRAM OF
Note 1: I/O pins have diode protection to VDD and VSS.
RB7:RB4 PINS
2: To enable weak pull-ups, set the appropriate TRIS bit(s)
and clear the RBPU bit (OPTION_REG<7>). VDD
RBPU(2) weak
P pull-up
Data Latch
Data bus
D Q
I/O
WR Port
CK pin(1)
TRIS Latch
D Q
WR TRIS TTL
CK
Input
Buffer ST
Buffer
RD TRIS Latch
Q D
RD Port EN Q1
Set RBIF
From other Q D
RB7:RB4 pins RD Port
EN
Q3
RB7:RB6 in serial programming mode
PIC16C77X
TABLE 3-3 PORTB FUNCTIONS
06h, 106h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx 11xx uuuu 11uu
86h, 186h TRISB PORTB Data Direction Register 1111 1111 1111 1111
81h, 181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
9Fh ADCON1 ADFM VCFG2 VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0 0000 0000 0000 0000
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.
PIC16C77X
3.3 PORTC and the TRISC Register FIGURE 3-9: PORTC BLOCK DIAGRAM
(PERIPHERAL OUTPUT
PORTC is an 8-bit wide bi-directional port. The corre-
OVERRIDE)
sponding data direction register is TRISC. Setting a
TRISC bit (=1) will make the corresponding PORTC pin
PORT/PERIPHERAL Select(2)
an input, i.e., put the corresponding output driver in a
hi-impedance mode. Clearing a TRISC bit (=0) will Peripheral Data Out VDD
make the corresponding PORTC pin an output, i.e., put 0
Data bus D Q
the contents of the output latch on the selected pin. WR P
1
PORT CK Q
PORTC is multiplexed with several peripheral functions
(Table 3-5). PORTC pins have Schmitt Trigger input Data Latch
buffers. D Q I/O
WR pin(1)
When enabling peripheral functions, care should be TRIS CK Q N
taken in defining TRIS bits for each PORTC pin. Some
peripherals override the TRIS bit to make a pin an out- TRIS Latch
VSS
put, while other peripherals override the TRIS bit to
make a pin an input. Since the TRIS bit override is in Schmitt
RD TRIS Trigger
effect while the peripheral is enabled, read-mod-
ify-write instructions (BSF, BCF, XORWF) with TRISC Peripheral
OE(3) Q D
as destination should be avoided. The user should refer
to the corresponding peripheral section for the correct EN
RD
TRIS bit settings. PORT
Peripheral input
EXAMPLE 3-1: INITIALIZING PORTC Note 1: I/O pins have diode protection to VDD and VSS.
BCF STATUS, RP0 ; Select Bank 0
2: Port/Peripheral select signal selects between port
CLRF PORTC ; Initialize PORTC by
data and peripheral output.
; clearing output
3: Peripheral OE (output enable) is only activated if
; data latches
peripheral select is active.
BSF STATUS, RP0 ; Select Bank 1
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISC ; Set RC<3:0> as inputs
; RC<5:4> as outputs
; RC<7:6> as inputs
PIC16C77X
TABLE 3-5 PORTC FUNCTIONS
RC0/T1OSO/T1CKI bit0 ST Input/output port pin or Timer1 oscillator output/Timer1 clock input
RC1/T1OSI/CCP2 bit1 ST Input/output port pin or Timer1 oscillator input or Capture2
input/Compare2 output/PWM2 output
RC2/CCP1 bit2 ST Input/output port pin or Capture1 input/Compare1 output/PWM1
output
RC3/SCK/SCL bit3 ST RC3 can also be the synchronous serial clock for both SPI and I2C
modes.
RC4/SDI/SDA bit4 ST RC4 can also be the SPI Data In (SPI mode) or data I/O (I2C mode).
RC5/SDO bit5 ST Input/output port pin or Synchronous Serial Port data output
RC6/TX/CK bit6 ST Input/output port pin or USART Asynchronous transmit or
Synchronous clock
RC7/RX/DT bit7 ST Input/output port pin or USART Asynchronous receive or
Synchronous data
Legend: ST = Schmitt Trigger input
07h PORTC RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0 xxxx xxxx uuuu uuuu
87h TRISC PORTC Data Direction Register 1111 1111 1111 1111
Legend: x = unknown, u = unchanged.
PIC16C77X
3.4 PORTD and TRISD Registers FIGURE 3-10: PORTD BLOCK DIAGRAM (IN
I/O PORT MODE)
This section is applicable to the 40/44-pin devices only.
Data
PORTD is an 8-bit port with Schmitt Trigger input buf- bus D Q
fers. Each pin is individually configurable as an input or
WR
output. PORT I/O pin(1)
CK
PORTD can be configured as an 8-bit wide micropro-
cessor port (parallel slave port) by setting control bit Data Latch
PSPMODE (TRISE<4>). In this mode, the input buffers D Q
are TTL. WR
TRIS CK Schmitt
Trigger
input
TRIS Latch buffer
RD TRIS
Q D
EN
EN
RD PORT
08h PORTD RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0 xxxx xxxx uuuu uuuu
88h TRISD PORTD Data Direction Register 1111 1111 1111 1111
89h TRISE IBF OBF IBOV PSPMODE PORTE Data Direction Bits 0000 -111 0000 -111
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by PORTD.
PIC16C77X
3.5 PORTE and TRISE Register FIGURE 3-11: PORTE BLOCK DIAGRAM (IN
I/O PORT MODE)
This section is applicable to the 40/44-pin devices only.
Data
PORTE has three pins RE0/RD/AN5, RE1/WR/AN6 bus D Q
and RE2/CS/AN7, which are individually configurable WR
as inputs or outputs. These pins have Schmitt Trigger PORT I/O pin(1)
CK
input buffers.
Data Latch
I/O PORTE becomes control inputs for the micropro-
D Q
cessor port when bit PSPMODE (TRISE<4>) is set. In
this mode, the user must make sure that the WR
TRIS CK Schmitt
TRISE<2:0> bits are set (pins are configured as digital Trigger
inputs). Ensure ADCON1 is configured for digital I/O. In input
TRIS Latch
this mode the input buffers are TTL. buffer
PIC16C77X
TABLE 3-9 PORTE FUNCTIONS
PIC16C77X
3.6 Parallel Slave Port FIGURE 3-13: PORTD AND PORTE BLOCK
DIAGRAM (PARALLEL SLAVE
The Parallel Slave Port is implemented on the
PORT)
40/44-pin devices only.
PORTD operates as an 8-bit wide Parallel Slave Port,
or microprocessor port when control bit PSPMODE Data bus
D Q
(TRISE<4>) is set. In slave mode it is asynchronously WR
readable and writable by the external world through RD RDx
PORT
CK pin
control input pin RE0/RD and WR control input pin
RE1/WR. TTL
Write
TTL WR
CS
WR
RD
PORTD<7:0>
IBF
OBF
PSPIF
PIC16C77X
FIGURE 3-15: PARALLEL SLAVE PORT READ WAVEFORMS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
CS
WR
RD
PORTD<7:0>
IBF
OBF
PSPIF
08h PORTD Port data latch when written: Port pins when read xxxx xxxx uuuu uuuu
09h PORTE RE2 RE1 RE0 ---- -xxx ---- -uuu
89h TRISE IBF OBF IBOV PSPMODE PORTE Data Direction Bits 0000 -111 0000 -111
0Ch PIR1 PSPIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
9Fh ADCON1 ADFM VCFG2 VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0 0000 0000 0000 0000
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by the Parallel Slave Port.
PIC16C77X
4.0 TIMER0 MODULE Additional information on external clock requirements
is available in the PICmicro Mid-Range Reference
The Timer0 module timer/counter has the following fea- Manual, (DS33023).
tures:
8-bit timer/counter 4.2 Prescaler
Readable and writable An 8-bit counter is available as a prescaler for the
Internal or external clock select Timer0 module, or as a postscaler for the Watchdog
Edge select for external clock Timer, respectively (Figure 4-2). For simplicity, this
8-bit software programmable prescaler counter is being referred to as prescaler throughout
Interrupt on overflow from FFh to 00h this data sheet. Note that there is only one prescaler
available which is mutually exclusively shared between
Figure 4-1 is a simplified block diagram of the Timer0 the Timer0 module and the Watchdog Timer. Thus, a
module. prescaler assignment for the Timer0 module means
Additional information on timer modules is available in that there is no prescaler for the Watchdog Timer, and
the PICmicro Mid-Range Reference Manual, vice-versa.
(DS33023). The prescaler is not readable or writable.
4.1 Timer0 Operation The PSA and PS2:PS0 bits (OPTION_REG<3:0>)
determine the prescaler assignment and prescale ratio.
Timer0 can operate as a timer or as a counter.
Clearing bit PSA will assign the prescaler to the Timer0
Timer mode is selected by clearing bit T0CS module. When the prescaler is assigned to the Timer0
(OPTION_REG<5>). In timer mode, the Timer0 mod- module, prescale values of 1:2, 1:4, ..., 1:256 are
ule will increment every instruction cycle (without pres- selectable.
caler). If the TMR0 register is written, the increment is
Setting bit PSA will assign the prescaler to the Watch-
inhibited for the following two instruction cycles. The
dog Timer (WDT). When the prescaler is assigned to
user can work around this by writing an adjusted value
the WDT, prescale values of 1:1, 1:2, ..., 1:128 are
to the TMR0 register.
selectable.
Counter mode is selected by setting bit T0CS
When assigned to the Timer0 module, all instructions
(OPTION_REG<5>). In counter mode, Timer0 will
writing to the TMR0 register (e.g. CLRF 1, MOVWF 1,
increment either on every rising or falling edge of pin
BSF 1,x....etc.) will clear the prescaler. When
RA4/T0CKI. The incrementing edge is determined by
assigned to WDT, a CLRWDT instruction will clear the
the Timer0 Source Edge Select bit T0SE
prescaler along with the WDT.
(OPTION_REG<4>). Clearing bit T0SE selects the ris-
ing edge. Restrictions on the external clock input are Note: Writing to TMR0 when the prescaler is
discussed in below. assigned to Timer0 will clear the prescaler
When an external clock input is used for Timer0, it must count, but will not change the prescaler
meet certain requirements. The requirements ensure assignment.
the external clock can be synchronized with the internal
phase clock (TOSC). Also, there is a delay in the actual
incrementing of Timer0 after synchronization.
Data bus
FOSC/4 0
PSout 8
1
Sync with
1 Internal TMR0
clocks
RA4/T0CKI Programmable 0 PSout
pin Prescaler
T0SE (2 cycle delay)
3
Set interrupt
PS2, PS1, PS0 PSA flag bit T0IF
T0CS on overflow
PIC16C77X
4.2.1 SWITCHING PRESCALER ASSIGNMENT 4.3 Timer0 Interrupt
The prescaler assignment is fully under software con- The TMR0 interrupt is generated when the TMR0 reg-
trol, i.e., it can be changed on the fly during program ister overflows from FFh to 00h. This overflow sets bit
execution. T0IF (INTCON<2>). The interrupt can be masked by
clearing bit T0IE (INTCON<5>). Bit T0IF must be
Note: To avoid an unintended device RESET, a
cleared in software by the Timer0 module interrupt ser-
specific instruction sequence (shown in the
vice routine before re-enabling this interrupt. The
PICmicro Mid-Range Reference Man-
TMR0 interrupt cannot awaken the processor from
ual, DS33023) must be executed when
SLEEP since the timer is shut off during SLEEP.
changing the prescaler assignment from
Timer0 to the WDT. This sequence must
be followed even if the WDT is disabled.
8
M 1
0
RA4/T0CKI U M
X SYNC
pin U 2 TMR0 reg
1 0
X Cycles
T0SE
T0CS
PSA Set flag bit T0IF
on Overflow
0
M 8-bit Prescaler
U
Watchdog 1 X 8
Timer
8 - to - 1MUX PS2:PS0
PSA
0 1
WDT Enable bit
MUX PSA
WDT
Time-out
PIC16C77X
5.0 TIMER1 MODULE 5.1 Timer1 Operation
The Timer1 module timer/counter has the following fea- Timer1 can operate in one of these modes:
tures:
As a timer
16-bit timer/counter As a synchronous counter
(Two 8-bit registers; TMR1H and TMR1L)
As an asynchronous counter
Readable and writable (Both registers)
The operating mode is determined by the clock select
Internal or external clock select
bit, TMR1CS (T1CON<1>).
Interrupt on overflow from FFFFh to 0000h
In timer mode, Timer1 increments every instruction
Reset from CCP module trigger
cycle. In counter mode, it increments on every rising
Timer1 has a control register, shown in Figure 5-1. edge of the external clock input.
Timer1 can be enabled/disabled by setting/clearing
When the Timer1 oscillator is enabled (T1OSCEN is
control bit TMR1ON (T1CON<0>).
set), the RC1/T1OSI and RC0/T1OSO/T1CKI pins
Figure 5-3 is a simplified block diagram of the Timer1 become inputs. That is, the TRISC<1:0> value is
module. ignored.
Additional information on timer modules is available in Timer1 also has an internal reset input. This reset can
the PICmicro Mid-Range Reference Manual, be generated by the CCP module (Section 7.0).
(DS33023).
TMR1CS = 1
1 = Do not synchronize external clock input
0 = Synchronize external clock input
TMR1CS = 0
This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0.
bit 1: TMR1CS: Timer1 Clock Source Select bit
1 = External clock from pin RC0/T1OSO/T1CKI (on the rising edge)
0 = Internal clock (FOSC/4)
bit 0: TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
PIC16C77X
5.1.1 TIMER1 COUNTER OPERATION
T1CKI
(Default high)
T1CKI
(Default low)
Note 1: When the T1OSCEN bit is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
PIC16C77X
5.2 Timer1 Oscillator 5.3 Timer1 Interrupt
A crystal oscillator circuit is built in between pins T1OSI The TMR1 Register pair (TMR1H:TMR1L) increments
(input) and T1OSO (amplifier output). It is enabled by from 0000h to FFFFh and rolls over to 0000h. The
setting control bit T1OSCEN (T1CON<3>). The oscilla- TMR1 Interrupt, if enabled, is generated on overflow
tor is a low power oscillator rated up to 200 kHz. It will which is latched in interrupt flag bit TMR1IF (PIR1<0>).
continue to run during SLEEP. It is primarily intended This interrupt can be enabled/disabled by setting/clear-
for a 32 kHz crystal. Table 5-1 shows the capacitor ing TMR1 interrupt enable bit TMR1IE (PIE1<0>).
selection for the Timer1 oscillator.
5.4 Resetting Timer1 using a CCP Trigger
The Timer1 oscillator is identical to the LP oscillator.
Output
The user must provide a software time delay to ensure
proper oscillator start-up. If the CCP module is configured in compare mode to
TABLE 5-1 CAPACITOR SELECTION FOR generate a special event trigger" (CCP1M3:CCP1M0
= 1011), this signal will reset Timer1 and start an A/D
THE TIMER1 OSCILLATOR
conversion (if the A/D module is enabled).
Osc Type Freq C1 C2 Note: The special event triggers from the CCP1
LP 32 kHz 33 pF 33 pF module will not set interrupt flag bit
100 kHz 15 pF 15 pF TMR1IF (PIR1<0>).
200 kHz 15 pF 15 pF Timer1 must be configured for either timer or synchro-
These values are for design guidance only. nized counter mode to take advantage of this feature. If
Timer1 is running in asynchronous counter mode, this
Crystals Tested: reset operation may not work.
32.768 kHz Epson C-001R32.768K-A 20 PPM In the event that a write to Timer1 coincides with a spe-
100 kHz Epson C-2 100.00 KC-P 20 PPM cial event trigger from CCP1, the write will take prece-
200 kHz STD XTL 200.000 kHz 20 PPM dence.
Note 1: Higher capacitance increases the stability In this mode of operation, the CCPR1H:CCPR1L regis-
of oscillator but also increases the start-up ters pair effectively becomes the period register for
time. Timer1.
2: Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for appropri-
ate values of external components.
TABLE 5-2 REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
0Bh,8Bh, INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
10Bh,18Bh
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
0Eh TMR1L Holding register for the Least Significant Byte of the 16-bit TMR1 register xxxx xxxx uuuu uuuu
0Fh TMR1H Holding register for the Most Significant Byte of the 16-bit TMR1 register xxxx xxxx uuuu uuuu
10h T1CON T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 --uu uuuu
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by the Timer1 module.
Note 1: These bits are reserved on the 28-pin devices, always maintain these bits clear.
PIC16C77X
NOTES:
PIC16C77X
6.0 TIMER2 MODULE 6.1 Timer2 Operation
The Timer2 module timer has the following features: Timer2 can be used as the PWM time-base for PWM
8-bit timer (TMR2 register) mode of the CCP module.
8-bit period register (PR2) The TMR2 register is readable and writable, and is
Readable and writable (Both registers) cleared on any device reset.
Software programmable prescaler (1:1, 1:4, 1:16) The input clock (FOSC/4) has a prescale option of 1:1,
Software programmable postscaler (1:1 to 1:16) 1:4 or 1:16, selected by control bits
Interrupt on TMR2 match of PR2 T2CKPS1:T2CKPS0 (T2CON<1:0>).
SSP module optional use of TMR2 output to gen- The match output of TMR2 goes through a 4-bit post-
erate clock shift scaler (which gives a 1:1 to 1:16 scaling inclusive) to
generate a TMR2 interrupt (latched in flag bit TMR2IF,
Timer2 has a control register, shown in Figure 6-1.
(PIR1<1>)).
Timer2 can be shut off by clearing control bit TMR2ON
(T2CON<2>) to minimize power consumption. The prescaler and postscaler counters are cleared
when any of the following occurs:
Figure 6-2 is a simplified block diagram of the Timer2
module. a write to the TMR2 register
Additional information on timer modules is available in a write to the T2CON register
the PICmicro Mid-Range Reference Manual, any device reset (Power-on Reset, MCLR reset,
(DS33023). Watchdog Timer reset, or Brown-out Reset)
TMR2 is not cleared when T2CON is written.
PIC16C77X
6.2 Timer2 Interrupt FIGURE 6-2: TIMER2 BLOCK DIAGRAM
The Timer2 module has an 8-bit period register PR2. Sets flag
TMR2
bit TMR2IF output (1)
Timer2 increments from 00h until it matches PR2 and
then resets to 00h on the next increment cycle. PR2 is
a readable and writable register. The PR2 register is ini- Reset Prescaler
TMR2 reg FOSC/4
tialized to FFh upon reset. 1:1, 1:4, 1:16
Postscaler 2
Comparator
6.3 Output of TMR2 1:1 to 1:16 EQ
The output of TMR2 (before the postscaler) is fed to the 4 PR2 reg
Synchronous Serial Port module which optionally uses
it to generate shift clock.
Note 1: TMR2 register output can be software selected
by the SSP Module as a baud clock.
0Bh,8Bh, INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
10Bh,18Bh
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
12h T2CON TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by the Timer2 module.
Note 1: These bits are reserved on the 28-pin, always maintain these bits clear.
PIC16C77X
7.0 CAPTURE/COMPARE/PWM CCP2 Module
(CCP) MODULE(S) Capture/Compare/PWM Register2 (CCPR2) is com-
prised of two 8-bit registers: CCPR2L (low byte) and
Each CCP (Capture/Compare/PWM) module contains
CCPR2H (high byte). The CCP2CON register controls
a 16-bit register which can operate as a 16-bit capture
the operation of CCP2. All are readable and writable.
register, as a 16-bit compare register or as a PWM
master/slave Duty Cycle register. Table 7-1 shows the Additional information on the CCP module is available
timer resources of the CCP module modes. in the PICmicro Mid-Range Reference Manual,
(DS33023).
The operation of CCP1 is identical to that of CCP2, with
the exception of the special trigger. Therefore, opera- TABLE 7-1 CCP MODE - TIMER
tion of a CCP module in the following sections is RESOURCE
described with respect to CCP1.
Table 7-2 shows the interaction of the CCP modules. CCP Mode Timer Resource
FIGURE 7-1: CCP1CON REGISTER (ADDRESS 17h) / CCP2CON REGISTER (ADDRESS 1Dh)
PIC16C77X
7.1 Capture Mode 7.1.4 CCP PRESCALER
In Capture mode, CCPR1H:CCPR1L captures the There are four prescaler settings, specified by bits
16-bit value of the TMR1 register when an event occurs CCP1M3:CCP1M0. Whenever the CCP module is
on pin RC2/CCP1. An event is defined as: turned off, or the CCP module is not in capture mode,
the prescaler counter is cleared. This means that any
every falling edge
reset will clear the prescaler counter.
every rising edge
Switching from one capture prescaler to another may
every 4th rising edge
generate an interrupt. Also, the prescaler counter will
every 16th rising edge not be cleared, therefore the first capture may be from
An event is selected by control bits CCP1M3:CCP1M0 a non-zero prescaler. Example 7-1 shows the recom-
(CCP1CON<3:0>). When a capture is made, the inter- mended method for switching between capture pres-
rupt request flag bit CCP1IF (PIR1<2>) is set. It must calers. This example also clears the prescaler counter
be cleared in software. If another capture occurs before and will not generate the false interrupt.
the value in register CCPR1 is read, the old captured
value will be lost. EXAMPLE 7-1: CHANGING BETWEEN
CAPTURE PRESCALERS
7.1.1 CCP PIN CONFIGURATION
CLRF CCP1CON ;Turn CCP module off
In Capture mode, the RC2/CCP1 pin should be config- MOVLW NEW_CAPT_PS ;Load the W reg with
; the new prescaler
ured as an input by setting the TRISC<2> bit.
; mode value and CCP ON
Note: If the RC2/CCP1 is configured as an out- MOVWF CCP1CON ;Load CCP1CON with this
put, a write to the port can cause a capture ; value
condition.
and Capture
edge detect Enable
TMR1H TMR1L
CCP1CON<3:0>
Qs
PIC16C77X
7.2 Compare Mode 7.2.1 CCP PIN CONFIGURATION
In Compare mode, the 16-bit CCPR1 register value is The user must configure the RC2/CCP1 pin as an out-
constantly compared against the TMR1 register pair put by clearing the TRISC<2> bit.
value. When a match occurs, the RC2/CCP1 pin is:
Note: Clearing the CCP1CON register will force
driven High the RC2/CCP1 compare output latch to the
driven Low default low level. This is not the data latch.
remains Unchanged
7.2.2 TIMER1 MODE SELECTION
The action on the pin is based on the value of control
bits CCP1M3:CCP1M0 (CCP1CON<3:0>). At the Timer1 must be running in Timer mode or Synchro-
same time, interrupt flag bit CCP1IF is set. nized Counter mode if the CCP module is using the
compare feature. In Asynchronous Counter mode, the
FIGURE 7-3: COMPARE MODE compare operation may not work.
OPERATION BLOCK 7.2.3 SOFTWARE INTERRUPT MODE
DIAGRAM
When generate software interrupt is chosen the CCP1
Special event trigger will:
pin is not affected. Only a CCP interrupt is generated (if
reset Timer1, but not set interrupt flag bit TMR1IF (PIR1<0>), enabled).
and set bit GO/DONE (ADCON0<2>)
which starts an A/D conversion 7.2.4 SPECIAL EVENT TRIGGER
Special Event Trigger (CCP2 only) In this mode, an internal hardware trigger is generated
which may be used to initiate an action.
Set flag bit CCP1IF
(PIR1<2>) The special event trigger output of CCP1 resets the
CCPR1H CCPR1L TMR1 register pair. This allows the CCPR1 register to
effectively be a 16-bit programmable period register for
Q S Output
Logic Comparator Timer1.
RC2/CCP1 R match
Pin The special trigger output of CCP2 resets the TMR1
TRISC<2> TMR1H TMR1L
Output Enable CCP1CON<3:0> register pair, and starts an A/D conversion (if the A/D
Mode Select module is enabled).
Note: The special event trigger from the CCP2
module will not set interrupt flag bit
TMR1IF (PIR1<0>).
TABLE 7-3 REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, AND TIMER1
0Bh,8Bh, INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
10Bh,18Bh
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
87h TRISC PORTC Data Direction Register 1111 1111 1111 1111
0Eh TMR1L Holding register for the Least Significant Byte of the 16-bit TMR1 register xxxx xxxx uuuu uuuu
0Fh TMR1H Holding register for the Most Significant Byte of the 16-bit TMR1register xxxx xxxx uuuu uuuu
10h T1CON T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 --uu uuuu
15h CCPR1L Capture/Compare/PWM register1 (LSB) xxxx xxxx uuuu uuuu
16h CCPR1H Capture/Compare/PWM register1 (MSB) xxxx xxxx uuuu uuuu
17h CCP1CON CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by Capture and Timer1.
Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin, always maintain these bits clear.
PIC16C77X
7.3 PWM Mode 7.3.1 PWM PERIOD
In Pulse Width Modulation (PWM) mode, the CCP1 pin The PWM period is specified by writing to the PR2 reg-
produces up to a 10-bit resolution PWM output. Since ister. The PWM period can be calculated using the fol-
the CCP1 pin is multiplexed with the PORTC data latch, lowing formula:
the TRISC<2> bit must be cleared to make the CCP1 PWM period = [(PR2) + 1] 4 TOSC
pin an output. (TMR2 prescale value)
Note: Clearing the CCP1CON register will force PWM frequency is defined as 1 / [PWM period].
the CCP1 PWM output latch to the default
When TMR2 is equal to PR2, the following three events
low level. This is not the PORTC I/O data
occur on the next increment cycle:
latch.
TMR2 is cleared
Figure 7-4 shows a simplified block diagram of the CCP
module in PWM mode. The CCP1 pin is set (exception: if PWM duty
cycle = 0%, the CCP1 pin will not be set)
For a step by step procedure on how to set up the CCP
The PWM duty cycle is latched from CCPR1L into
module for PWM operation, see Section 7.3.3.
CCPR1H
FIGURE 7-4: SIMPLIFIED PWM BLOCK Note: The Timer2 postscaler (see Section 6.0) is
not used in the determination of the PWM
DIAGRAM
frequency. The postscaler could be used to
CCP1CON<5:4> have a servo update rate at a different fre-
Duty cycle registers
quency than the PWM output.
CCPR1L
7.3.2 PWM DUTY CYCLE
TMR2 = PR2
Note: If the PWM duty cycle value is longer than
TMR2 = Duty Cycle the PWM period the CCP1 pin will not be
cleared.
TMR2 = PR2
For an example PWM period and duty cycle calcu-
lation, see the PICmicro Mid-Range Reference
Manual, (DS33023).
PIC16C77X
7.3.3 SET-UP FOR PWM OPERATION
PWM Frequency 1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz
Timer Prescaler (1, 4, 16) 16 4 1 1 1 1
PR2 Value 0xFF 0xFF 0xFF 0x3F 0x1F 0x17
Maximum Resolution (bits) 10 10 10 8 7 5.5
TABLE 7-5 REGISTERS ASSOCIATED WITH PWM AND TIMER2
0Bh,8Bh, INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
10Bh,18Bh
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
87h TRISC PORTC Data Direction Register 1111 1111 1111 1111
11h TMR2 Timer2 modules register 0000 0000 0000 0000
92h PR2 Timer2 modules period register 1111 1111 1111 1111
12h T2CON TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
15h CCPR1L Capture/Compare/PWM register1 (LSB) xxxx xxxx uuuu uuuu
16h CCPR1H Capture/Compare/PWM register1 (MSB) xxxx xxxx uuuu uuuu
17h CCP1CON CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by PWM and Timer2.
Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin, always maintain these bits clear.
PIC16C77X
NOTES:
PIC16C77X
8.0 MASTER SYNCHRONOUS
SERIAL PORT (MSSP)
MODULE
The Master Synchronous Serial Port (MSSP) module is
a serial interface useful for communicating with other
peripheral or microcontroller devices. These peripheral
devices may be serial EEPROMs, shift registers, dis-
play drivers, A/D converters, etc. The MSSP module
can operate in one of two modes:
Serial Peripheral Interface (SPI)
Inter-Integrated Circuit (I 2C)
PIC16C77X
FIGURE 8-1: SSPSTAT: SYNC SERIAL PORT STATUS REGISTER (ADDRESS: 94h)
PIC16C77X
FIGURE 8-2: SSPCON: SYNC SERIAL PORT CONTROL REGISTER (ADDRESS 14h)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 R = Readable bit
bit7 bit0 W = Writable bit
- n = Value at POR reset
bit 7: WCOL: Write Collision Detect bit
Master Mode:
1 = A write to the SSPBUF register was attempted while the I2C conditions were not valid for a
transmission to be started
0 = No collision
Slave Mode:
1 = The SSPBUF register is written while it is still transmitting the previous word
(must be cleared in software)
0 = No collision
bit 6: SSPOV: Receive Overflow Indicator bit
In SPI mode
1 = A new byte is received while the SSPBUF register is still holding the previous data. In case of overflow,
the data in SSPSR is lost. Overflow can only occur in slave mode. In slave mode, the user must read the
SSPBUF, even if only transmitting data, to avoid setting overflow. In master mode, the overflow bit is not
set since each new reception (and transmission) is initiated by writing to the SSPBUF register. (Must be
cleared in software).
0 = No overflow
In I2C mode
1 = A byte is received while the SSPBUF register is still holding the previous byte. SSPOV is a "dont care"
in transmit mode. (Must be cleared in software).
0 = No overflow
bit 5: SSPEN: Synchronous Serial Port Enable bit
In both modes, when enabled, these pins must be properly configured as input or output.
In SPI mode
1 = Enables serial port and configures SCK, SDO, SDI, and SS as the source of the serial port pins
0 = Disables serial port and configures these pins as I/O port pins
In I2C mode
1 = Enables the serial port and configures the SDA and SCL pins as the source of the serial port pins
0 = Disables serial port and configures these pins as I/O port pins
bit 4: CKP: Clock Polarity Select bit
In SPI mode
1 = Idle state for clock is a high level
0 = Idle state for clock is a low level
In I2C slave mode
SCK release control
1 = Enable clock
0 = Holds clock low (clock stretch) (Used to ensure data setup time)
In I2C master mode
Unused in this mode
bit 3-0: SSPM3:SSPM0: Synchronous Serial Port Mode Select bits
0000 = SPI master mode, clock = FOSC/4
0001 = SPI master mode, clock = FOSC/16
0010 = SPI master mode, clock = FOSC/64
0011 = SPI master mode, clock = TMR2 output/2
0100 = SPI slave mode, clock = SCK pin. SS pin control enabled.
0101 = SPI slave mode, clock = SCK pin. SS pin control disabled. SS can be used as I/O pin
0110 = I2C slave mode, 7-bit address
0111 = I2C slave mode, 10-bit address
1000 = I2C master mode, clock = FOSC / (4 * (SSPADD+1) )
1xx1 = Reserved
1x1x = Reserved
PIC16C77X
FIGURE 8-3: SSPCON2: SYNC SERIAL PORT CONTROL REGISTER2 (ADDRESS 91h)
PIC16C77X
8.1 SPI Mode FIGURE 8-4: MSSP BLOCK DIAGRAM
(SPI MODE)
The SPI mode allows 8-bits of data to be synchro-
Internal
nously transmitted and received simultaneously. All data bus
four modes of SPI are supported. To accomplish com-
munication, typically three pins are used: Read Write
PIC16C77X
determine when the transmission/reception has com- SDI, SDO, SCK, and SS pins as serial port pins. For the
pleted. The SSPBUF must be read and/or written. If the pins to behave as the serial port function, some must
interrupt method is not going to be used, then software have their data direction bits (in the TRIS register)
polling can be done to ensure that a write collision does appropriately programmed. That is:
not occur. Example 8-1 shows the loading of the SDI is automatically controlled by the SPI module
SSPBUF (SSPSR) for data transmission.
SDO must have TRISC<5> cleared
SCK (Master mode) must have TRISC<3>
EXAMPLE 8-1: LOADING THE SSPBUF
cleared
(SSPSR) REGISTER
BSF STATUS, RP0 ;Specify Bank 1 SCK (Slave mode) must have TRISC<3> set
LOOP BTFSS SSPSTAT, BF ;Has data been SS must have TRISA<5> set
;received
Any serial port function that is not desired may be over-
;(transmit
ridden by programming the corresponding data direc-
;complete)?
tion (TRIS) register to the opposite value.
GOTO LOOP ;No
BCF STATUS, RP0 ;Specify Bank 0 8.1.3 TYPICAL CONNECTION
MOVF SSPBUF, W ;W reg = contents
;of SSPBUF Figure 8-5 shows a typical connection between two
MOVWF RXDATA ;Save in user RAM microcontrollers. The master controller (Processor 1)
MOVF TXDATA, W ;W reg = contents initiates the data transfer by sending the SCK signal.
; of TXDATA Data is shifted out of both shift registers on their pro-
MOVWF SSPBUF ;New data to xmit grammed clock edge, and latched on the opposite edge
of the clock. Both processors should be programmed to
The SSPSR is not directly readable or writable, and can same Clock Polarity (CKP), then both controllers would
only be accessed by addressing the SSPBUF register. send and receive data at the same time. Whether the
Additionally, the MSSP status register (SSPSTAT) indi- data is meaningful (or dummy data) depends on the
cates the various status conditions. application software. This leads to three scenarios for
8.1.2 ENABLING SPI I/O data transmission:
Master sends dataSlave sends dummy data
To enable the serial port, MSSP Enable bit, SSPEN
Master sends dataSlave sends data
(SSPCON<5>) must be set. To reset or reconfigure SPI
mode, clear bit SSPEN, re-initialize the SSPCON reg- Master sends dummy dataSlave sends data
isters, and then set bit SSPEN. This configures the
SDO SDI
SDI SDO
Shift Register Shift Register
(SSPSR) (SSPSR)
PROCESSOR 1 PROCESSOR 2
PIC16C77X
8.1.4 MASTER MODE Figure 8-6, Figure 8-8, and Figure 8-9 where the MSb
is transmitted first. In master mode, the SPI clock rate
The master can initiate the data transfer at any time (bit rate) is user programmable to be one of the follow-
because it controls the SCK. The master determines ing:
when the slave (Processor 2, Figure 8-5) is to broad-
cast data by the software protocol. FOSC/4 (or TCY)
FOSC/16 (or 4 TCY)
In master mode the data is transmitted/received as
soon as the SSPBUF register is written to. If the SPI FOSC/64 (or 16 TCY)
module is only going to receive, the SDO output could Timer2 output/2
be disabled (programmed as an input). The SSPSR This allows a maximum bit clock frequency (at 20 MHz)
register will continue to shift in the signal present on the of 8.25 MHz.
SDI pin at the programmed clock rate. As each byte is
Figure 8-6 shows the waveforms for Master mode.
received, it will be loaded into the SSPBUF register as
When CKE = 1, the SDO data is valid before there is a
if a normal received byte (interrupts and status bits
clock edge on SCK. The change of the input sample is
appropriately set). This could be useful in receiver
shown based on the state of the SMP bit. The time
applications as a line activity monitor.
when the SSPBUF is loaded with the received data is
The clock polarity is selected by appropriately program- shown.
ming bit CKP (SSPCON<4>). This then would give
waveforms for SPI communication as shown in
SCK
(CKP = 0
CKE = 0)
SCK
(CKP = 1
CKE = 0)
4 clock
SCK modes
(CKP = 0
CKE = 1)
SCK
(CKP = 1
CKE = 1)
Input
Sample
(SMP = 1)
SSPIF
Next Q4 cycle
SSPSR to after Q2
SSPBUF
PIC16C77X
8.1.5 SLAVE MODE SDO pin is no longer driven, even if in the middle of
a transmitted byte, and becomes a floating output.
In slave mode, the data is transmitted and received as External pull-up/ pull-down resistors may be desirable,
the external clock pulses appear on SCK. When the depending on the application.
last bit is latched the interrupt flag bit SSPIF (PIR1<3>)
is set. Note: When the SPI module is in Slave Mode
with SS pin control enabled, (SSP-
While in slave mode the external clock is supplied by
CON<3:0> = 0100) the SPI module will
the external clock source on the SCK pin. This external
reset if the SS pin is set to VDD.
clock must meet the minimum high and low times as
specified in the electrical specifications. Note: If the SPI is used in Slave Mode with
CKE = '1', then SS pin control must be
While in sleep mode, the slave can transmit/receive
enabled.
data. When a byte is received the device will wake-up
from sleep. When the SPI module resets, the bit counter is forced
to 0. This can be done by either forcing the SS pin to a
8.1.6 SLAVE SELECT SYNCHRONIZATION high level or clearing the SSPEN bit.
The SS pin allows a synchronous slave mode. The To emulate two-wire communication, the SDO pin can
SPI must be in slave mode with SS pin control be connected to the SDI pin. When the SPI needs to
enabled (SSPCON<3:0> = 0100). The pin must not operate as a receiver the SDO pin can be configured as
be driven low for the SS pin to function as an input. an input. This disables transmissions from the SDO.
TRISA<5> must be set. When the SS pin is low, The SDI can always be left as an input (SDI function)
transmission and reception are enabled and the since it cannot create a bus conflict.
SDO pin is driven. When the SS pin goes high, the
SS
SCK
(CKP = 0
CKE = 0)
SCK
(CKP = 1
CKE = 0)
Write to
SSPBUF
SDI bit0
(SMP = 0) bit7 bit7
Input
Sample
(SMP = 0)
SSPIF
Interrupt
Flag
Next Q4 cycle
SSPSR to after Q2
SSPBUF
PIC16C77X
FIGURE 8-8: SPI SLAVE MODE WAVEFORM (CKE = 0)
SS
optional
SCK
(CKP = 0
CKE = 0)
SCK
(CKP = 1
CKE = 0)
Write to
SSPBUF
SDI
(SMP = 0) bit7 bit0
Input
Sample
(SMP = 0)
SSPIF
Interrupt
Flag
Next Q4 cycle
after Q2
SSPSR to
SSPBUF
SCK
(CKP = 1
CKE = 1)
Write to
SSPBUF
SDI
(SMP = 0) bit0
bit7
Input
Sample
(SMP = 0)
SSPIF
Interrupt
Flag
Next Q4 cycle
after Q2
SSPSR to
SSPBUF
PIC16C77X
8.1.7 SLEEP OPERATION 8.1.8 EFFECTS OF A RESET
In master mode all module clocks are halted, and the A reset disables the MSSP module and terminates the
transmission/reception will remain in that state until the current transfer.
device wakes from sleep. After the device returns to
normal mode, the module will continue to transmit/
receive data.
In slave mode, the SPI transmit/receive shift register
operates asynchronously to the device. This allows the
device to be placed in sleep mode, and data to be
shifted into the SPI transmit/receive shift register.
When all 8-bits have been received, the MSSP interrupt
flag bit will be set and if enabled will wake the device
from sleep.
TABLE 8-1 REGISTERS ASSOCIATED WITH SPI OPERATION
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR, BOR MCLR, WDT
0Bh, 8Bh,
INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
10Bh,18Bh
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
13h SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu
14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000
94h SSPSTAT SMP CKE D/A P S R/W UA BF 0000 0000 0000 0000
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by the SSP in SPI mode.
Note 1: These bits are reserved on the 28-pin devices, always maintain these bits clear.
PIC16C77X
8.2 MSSP I 2C Operation FIGURE 8-11: I2C MASTER MODE BLOCK
DIAGRAM
The MSSP module in I 2C mode fully implements all
master and slave functions (including general call sup- Internal
data bus
port) and provides interrupts on start and stop bits in
hardware to determine a free bus (multi-master func- Read Write
tion). The MSSP module implements the standard SSPADD<6:0>
7
mode specifications as well as 7-bit and 10-bit address-
ing. Baud Rate Generator
FIGURE 8-10: I2C SLAVE MODE BLOCK Match detect Addr Match
DIAGRAM
Internal SSPADD reg
data bus
Read Write Start and Stop bit Set/Clear S bit
and
detect / generate Clear/Set P bit
SSPBUF reg (SSPSTAT reg)
SCL and Set SSPIF
shift
clock Two pins are used for data transfer. These are the SCL
pin, which is the clock, and the SDA pin, which is the
SSPSR reg
data. The SDA and SCL pins that are automatically
SDA MSb LSb
configured when the I2C mode is enabled. The SSP
module functions are enabled by setting SSP Enable
Match detect Addr Match bit SSPEN (SSPCON<5>).
The MSSP module has six registers for I2C operation.
They are the:
SSPADD reg
SSP Control Register (SSPCON)
Start and Set, Reset SSP Control Register2 (SSPCON2)
Stop bit detect S, P bits SSP Status Register (SSPSTAT)
(SSPSTAT reg)
Serial Receive/Transmit Buffer (SSPBUF)
SSP Shift Register (SSPSR) - Not directly acces-
sible
SSP Address Register (SSPADD)
The SSPCON register allows control of the I 2C opera-
tion. Four mode selection bits (SSPCON<3:0>) allow
one of the following I 2C modes to be selected:
I 2C Slave mode (7-bit address)
I 2C Slave mode (10-bit address)
I 2C Master mode, clock = OSC/4 (SSPADD +1)
Before selecting any I 2C mode, the SCL and SDA pins
must be programmed to inputs by setting the appropri-
ate TRIS bits. Selecting an I 2C mode, by setting the
SSPEN bit, enables the SCL and SDA pins to be used
as the clock and data lines in I 2C mode.
PIC16C77X
The SSPSTAT register gives the status of the data 8.2.1.1 ADDRESSING
transfer. This information includes detection of a
START (S) or STOP (P) bit, specifies if the received Once the MSSP module has been enabled, it waits for
byte was data or address if the next byte is the comple- a START condition to occur. Following the START con-
tion of 10-bit address, and if this will be a read or write dition, the 8-bits are shifted into the SSPSR register. All
data transfer. incoming bits are sampled with the rising edge of the
clock (SCL) line. The value of register SSPSR<7:1> is
SSPBUF is the register to which the transfer data is compared to the value of the SSPADD register. The
written to or read from. The SSPSR register shifts the address is compared on the falling edge of the eighth
data in or out of the device. In receive operations, the clock (SCL) pulse. If the addresses match, and the BF
SSPBUF and SSPSR create a doubled buffered and SSPOV bits are clear, the following events occur:
receiver. This allows reception of the next byte to begin
before reading the last byte of received data. When the a) The SSPSR register value is loaded into the
complete byte is received, it is transferred to the SSPBUF register on the falling edge of the 8th
SSPBUF register and flag bit SSPIF is set. If another SCL pulse.
complete byte is received before the SSPBUF register b) The buffer full bit, BF is set on the falling edge of
is read, a receiver overflow has occurred and bit the 8th SCL pulse.
SSPOV (SSPCON<6>) is set and the byte in the c) An ACK pulse is generated.
SSPSR is lost. d) SSP interrupt flag bit, SSPIF (PIR1<3>) is set
The SSPADD register holds the slave address. In 10-bit (interrupt is generated if enabled) - on the falling
mode, the user needs to write the high byte of the edge of the 9th SCL pulse.
address (1111 0 A9 A8 0). Following the high byte In 10-bit address mode, two address bytes need to be
address match, the low byte of the address needs to be received by the slave. The five Most Significant bits
loaded (A7:A0). (MSbs) of the first address byte specify if this is a 10-bit
address. Bit R/W (SSPSTAT<2>) must specify a write
8.2.1 SLAVE MODE
so the slave device will receive the second address
In slave mode, the SCL and SDA pins must be config- byte. For a 10-bit address the first byte would equal
ured as inputs. The MSSP module will override the 1111 0 A9 A8 0, where A9 and A8 are the two MSbs
input state with the output data when required (slave- of the address. The sequence of events for a 10-bit
transmitter). address is as follows, with steps 7- 9 for slave-transmit-
ter:
When an address is matched or the data transfer after
an address match is received, the hardware automati- 1. Receive first (high) byte of Address (bits SSPIF,
cally will generate the acknowledge (ACK) pulse, and BF, and bit UA (SSPSTAT<1>) are set).
then load the SSPBUF register with the received value 2. Update the SSPADD register with second (low)
currently in the SSPSR register. byte of Address (clears bit UA and releases the
There are certain conditions that will cause the MSSP SCL line).
module not to give this ACK pulse. These are if either 3. Read the SSPBUF register (clears bit BF) and
(or both): clear flag bit SSPIF.
a) The buffer full bit BF (SSPSTAT<0>) was set 4. Receive second (low) byte of Address (bits
before the transfer was received. SSPIF, BF, and UA are set).
b) The overflow bit SSPOV (SSPCON<6>) was set 5. Update the SSPADD register with the first (high)
before the transfer was received. byte of Address. This will clear bit UA and
release the SCL line.
If the BF bit is set, the SSPSR register value is not
6. Read the SSPBUF register (clears bit BF) and
loaded into the SSPBUF, but bit SSPIF and SSPOV are
clear flag bit SSPIF.
set. Table 8-2 shows what happens when a data trans-
fer byte is received, given the status of bits BF and 7. Receive Repeated Start condition.
SSPOV. The shaded cells show the condition where 8. Receive first (high) byte of Address (bits SSPIF
user software did not properly clear the overflow condi- and BF are set).
tion. Flag bit BF is cleared by reading the SSPBUF reg- 9. Read the SSPBUF register (clears bit BF) and
ister while bit SSPOV is cleared through software. clear flag bit SSPIF.
The SCL clock input must have a minimum high and Note: Following the Repeated Start condition
low time for proper operation. The high and low times (step 7) in 10-bit mode, the user only
of the I2C specification as well as the requirement of the needs to match the first 7-bit address. The
MSSP module is shown in timing parameter #100 and user does not update the SSPADD for the
parameter #101 of the Electrical Specifications. second half of the address.
PIC16C77X
8.2.1.2 SLAVE RECEPTION An SSP interrupt is generated for each data transfer
byte. Flag bit SSPIF (PIR1<3>) must be cleared in soft-
When the R/W bit of the address byte is clear and an ware. The SSPSTAT register is used to determine the
address match occurs, the R/W bit of the SSPSTAT status of the received byte.
register is cleared. The received address is loaded into
the SSPBUF register. Note: The SSPBUF will be loaded if the SSPOV
bit is set and the BF flag is cleared. If a
When the address byte overflow condition exists, then
read of the SSPBUF was performed, but
no acknowledge (ACK) pulse is given. An overflow con-
the user did not clear the state of the
dition is defined as either bit BF (SSPSTAT<0>) is set
SSPOV bit before the next receive
or bit SSPOV (SSPCON<6>) is set.
occured. The ACK is not sent and the SSP-
BUF is updated.
TABLE 8-2 DATA TRANSFER RECEIVED BYTE ACTIONS
8.2.1.3 SLAVE TRANSMISSION An SSP interrupt is generated for each data transfer
byte. The SSPIF flag bit must be cleared in software,
When the R/W bit of the incoming address byte is set and the SSPSTAT register is used to determine the sta-
and an address match occurs, the R/W bit of the tus of the byte tranfer. The SSPIF flag bit is set on the
SSPSTAT register is set. The received address is falling edge of the ninth clock pulse.
loaded into the SSPBUF register. The ACK pulse will
be sent on the ninth bit, and the SCL pin is held low. As a slave-transmitter, the ACK pulse from the master-
The transmit data must be loaded into the SSPBUF receiver is latched on the rising edge of the ninth SCL
register, which also loads the SSPSR register. Then the input pulse. If the SDA line was high (not ACK), then the
SCL pin should be enabled by setting bit CKP (SSP- data transfer is complete. When the not ACK is latched
CON<4>). The master must monitor the SCL pin prior by the slave, the slave logic is reset and the slave then
to asserting another clock pulse. The slave devices monitors for another occurrence of the START bit. If the
may be holding off the master by stretching the clock. SDA line was low (ACK), the transmit data must be
The eight data bits are shifted out on the falling edge of loaded into the SSPBUF register, which also loads the
the SCL input. This ensures that the SDA signal is valid SSPSR register. Then the SCL pin should be enabled
during the SCL high time (Figure 8-13). by setting the CKP bit.
SCL S 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 P
PIC16C77X
FIGURE 8-13: I 2C WAVEFORMS FOR TRANSMISSION (7-BIT ADDRESS)
R/W = 1 R/W = 0
Receiving Address ACK Transmitting Data Not ACK
SDA A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0
SCL 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
S P
Data in SCL held low
sampled while CPU
responds to SSPIF
SSPIF
BF (SSPSTAT<0>)
cleared in software From SSP interrupt
SSPBUF is written in software service routine
CKP (SSPCON<4>)
SCL 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
S Sr P
SSPIF
(PIR1<3>)
Cleared in software Cleared in software Cleared in software Bus Master
terminates
transfer
BF (SSPSTAT<0>)
Advance Information
UA (SSPSTAT<1>)
DS30275B-page 67
PIC16C77X
DS30275B-page 68
PIC16C77X
Bus Master
774.book Page 68 Tuesday, January 29, 2013 12:02 PM
Receive First Byte of Address Receive Second Byte of Address Receive Data Byte
R/W = 0 R/W = 1
ACK ACK
SDA 1 1 1 1 0 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 ACK
SCL 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
S P
SSPIF
(PIR1<3>)
Cleared in software Cleared in software
BF (SSPSTAT<0>)
FIGURE 8-15: I2C SLAVE-RECEIVER (10-BIT ADDRESS)
SSPBUF is written with Dummy read of SSPBUF Dummy read of SSPBUF Read of SSPBUF
contents of SSPSR to clear BF flag to clear BF flag clears BF flag
Advance Information
UA (SSPSTAT<1>)
PIC16C77X
8.2.2 GENERAL CALL ADDRESS SUPPORT If the general call address matches, the SSPSR is
transfered to the SSPBUF, the BF flag is set (eighth bit),
The addressing procedure for the I2C bus is such that and on the falling edge of the ninth bit (ACK bit) the
the first byte after the START condition usually deter- SSPIF flag is set.
mines which device will be the slave addressed by the
master. The exception is the general call address which When the interrupt is serviced. The source for the
can address all devices. When this address is used, all interrupt can be checked by reading the contents of the
devices should, in theory, respond with an acknowl- SSPBUF to determine if the address was device spe-
edge. cific or a general call address.
The general call address is one of eight addresses In 10-bit mode, the SSPADD is required to be updated
reserved for specific purposes by the I2C protocol. It for the second half of the address to match, and the UA
consists of all 0s with R/W = 0 bit is set (SSPSTAT<1>). If the general call address is
sampled when GCEN is set while the slave is config-
The general call address is recognized when the Gen- ured in 10-bit address mode, then the second half of
eral Call Enable bit (GCEN) is enabled (SSPCON2<7> the address is not necessary, the UA bit will not be set,
is set). Following a start-bit detect, 8-bits are shifted and the slave will begin receiving data after the
into SSPSR and the address is compared against acknowledge (Figure 8-16).
SSPADD, and is also compared to the general call
address, fixed in hardware.
FIGURE 8-16: SLAVE MODE GENERAL CALL ADDRESS SEQUENCE (7 OR 10-BIT MODE)
SCL
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
S
SSPIF
BF
(SSPSTAT<0>)
Cleared in software
SSPBUF is read
SSPOV '0'
(SSPCON<6>)
GCEN '1'
(SSPCON2<7>)
PIC16C77X
8.2.3 SLEEP OPERATION 8.2.4 EFFECTS OF A RESET
2
While in sleep mode, the I C module can receive A reset diables the SSP module and terminates the
addresses or data, and when an address match or current transfer.
complete byte transfer occurs wake the processor from
sleep (if the SSP interrupt is enabled).
TABLE 8-3 REGISTERS ASSOCIATED WITH I2C OPERATION
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR, BOR MCLR, WDT
0Bh, 8Bh,
INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
10Bh,18Bh
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
13h SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu
14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000
91h SSPCON2 GCEN AKSTAT AKDT AKEN RCEN PEN RSEN SEN 0000 0000 0000 0000
94h SSPSTAT SMP CKE D/A P S R/W UA BF 0000 0000 0000 0000
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by the SSP in I2C mode.
Note 1: These bits are reserved on the 28-pin devices, always maintain these bits clear.
2: These bits are reserved on these devices, always maintain these bits clear.
PIC16C77X
8.2.5 MASTER MODE In master mode, the SCL and SDA lines are manipu-
lated by the MSSP hardware.
Master mode of operation is supported by interrupt
generation on the detection of the START and STOP The following events will cause SSP Interrupt Flag bit,
conditions. The STOP (P) and START (S) bits are SSPIF, to be set (SSP Interrupt if enabled):
cleared from a reset or when the MSSP module is dis- START condition
abled. Control of the I 2C bus may be taken when the P STOP condition
bit is set, or the bus is idle with both the S and P bits Data transfer byte transmitted/received
clear.
Acknowledge transmit
Repeated Start
Internal SSPM3:SSPM0,
data bus SSPADD<6:0>
Read Write
SSPBUF Baud
rate
generator
SDA shift
clock cntl
Acknowledge
Generate
SCL
PIC16C77X
8.2.6 MULTI-MASTER OPERATION 8.2.7.4 I2C MASTER MODE OPERATION
In multi-master mode, the interrupt generation on the The master device generates all of the serial clock
detection of the START and STOP conditions allows pulses and the START and STOP conditions. A trans-
the determination of when the bus is free. The STOP fer is ended with a STOP condition or with a Repeated
(P) and START (S) bits are cleared from a reset or Start condition. Since the Repeated Start condition is
when the MSSP module is disabled. Control of the I 2C also the beginning of the next serial transfer, the I2C
bus may be taken when bit P (SSPSTAT<4>) is set, or bus will not be released.
the bus is idle with both the S and P bits clear. When In Master Transmitter mode, serial data is output
the bus is busy, enabling the SSP Interrupt will gener- through SDA, while SCL outputs the serial clock. The
ate the interrupt when the STOP condition occurs. first byte transmitted contains the slave address of the
In multi-master operation, the SDA line must be moni- receiving device (7 bits) and the Read/Write (R/W) bit.
tored, for abitration, to see if the signal level is the In this case, the R/W bit will be logic '0'. Serial data is
expected output level. This check is performed in hard- transmitted 8 bits at a time. After each byte is transmit-
ware, with the result placed in the BCLIF bit. ted, an acknowledge bit is received. START and STOP
The states where arbitration can be lost are: conditions are output to indicate the beginning and the
end of a serial transfer.
Address Transfer
Data Transfer In Master receive mode the first byte transmitted con-
A Start Condition tains the slave address of the transmitting device
A Repeated Start Condition (7 bits) and the R/W bit. In this case the R/W bit will be
An Acknowledge Condition logic '1'. Thus the first byte transmitted is a 7-bit slave
address followed by a '1' to indicate receive bit. Serial
8.2.7 I2C MASTER OPERATION SUPPORT data is received via SDA while SCL outputs the serial
clock. Serial data is received 8 bits at a time. After each
Master Mode is enabled by setting and clearing the byte is received, an acknowledge bit is transmitted.
appropriate SSPM bits in SSPCON and by setting the START and STOP conditions indicate the beginning
SSPEN bit. Once master mode is enabled, the user and end of transmission.
has six options.
The baud rate generator used for SPI mode operation
- Assert a start condition on SDA and SCL. is now used to set the SCL clock frequency for either
- Assert a Repeated Start condition on SDA and 100 kHz, 400 kHz, or 1 MHz I2C operation. The baud
SCL. rate generator reload value is contained in the lower 7
- Write to the SSPBUF register initiating trans- bits of the SSPADD register. The baud rate generator
mission of data/address. will automatically begin counting on a write to the SSP-
- Generate a stop condition on SDA and SCL. BUF. Once the given operation is complete (i.e. trans-
- Configure the I2C port to receive data. mission of the last data bit is followed by ACK), the
- Generate an Acknowledge condition at the end internal clock will automatically stop counting and the
of a received byte of data. SCL pin will remain in its last state
A typical transmit sequence would go as follows:
Note: The MSSP Module, when configured in I2C a) The user generates a Start Condition by setting
Master Mode, does not allow queueing of the START enable bit (SEN) in SSPCON2.
events. For instance: The user is not b) SSPIF is set. The module will wait the required
allowed to initiate a start condition, and start time before any other operation takes
immediately write the SSPBUF register to place.
initiate transmission before the START c) The user loads the SSPBUF with address to
condition is complete. In this case the transmit.
SSPBUF will not be written to, and the
d) Address is shifted out the SDA pin until all 8 bits
WCOL bit will be set, indicating that a write
are transmitted.
to the SSPBUF did not occur.
e) The MSSP Module shifts in the ACK bit from the
slave device, and writes its value into the
SSPCON2 register ( SSPCON2<6>).
f) The module generates an interrupt at the end of
the ninth clock cycle by setting SSPIF.
g) The user loads the SSPBUF with eight bits of
data.
h) DATA is shifted out the SDA pin until all 8 bits
are transmitted.
PIC16C77X
i) The MSSP Module shifts in the ACK bit from the In I2C master mode, the BRG is reloaded automatically.
slave device, and writes its value into the If Clock Arbitration is taking place for instance, the BRG
SSPCON2 register ( SSPCON2<6>). will be reloaded when the SCL pin is sampled high
j) The MSSP module generates an interrupt at the (Figure 8-19).
end of the ninth clock cycle by setting the SSPIF
bit. FIGURE 8-18: BAUD RATE GENERATOR
k) The user generates a STOP condition by setting BLOCK DIAGRAM
the STOP enable bit PEN in SSPCON2.
SSPM3:SSPM0 SSPADD<6:0>
l) Interrupt is generated once the STOP condition
is complete.
SDA DX DX-1
BRG decrements
(on Q2 and Q4 cycles)
BRG
03h 02h 01h 00h (hold off) 03h 02h
value
PIC16C77X
8.2.9 I2C MASTER MODE START CONDITION 8.2.9.5 WCOL STATUS FLAG
TIMING
If the user writes the SSPBUF when an START
To initiate a START condition, the user sets the start sequence is in progress, then WCOL is set and the
condition enable bit, SEN (SSPCON2<0>). If the SDA contents of the buffer are unchanged (the write doesnt
and SCL pins are sampled high, the baud rate genera- occur).
tor is re-loaded with the contents of SSPADD<6:0>,
Note: Because queueing of events is not
and starts its count. If SCL and SDA are both sampled
allowed, writing to the lower 5 bits of
high when the baud rate generator times out (TBRG),
SSPCON2 is disabled until the START
the SDA pin is driven low. The action of the SDA being
condition is complete.
driven low while SCL is high is the START condition,
and causes the S bit (SSPSTAT<3>) to be set. Follow-
ing this, the baud rate generator is reloaded with the
contents of SSPADD<6:0> and resumes its count.
When the baud rate generator times out (TBRG), the
SEN bit (SSPCON2<0>) will be automatically cleared
by hardware, the baud rate generator is suspended
leaving the SDA line held low, and the START condition
is complete.
Note: If at the beginning of START condition the
SDA and SCL pins are already sampled
low, or if during the START condition the
SCL line is sampled low before the SDA
line is driven low, a bus collision occurs, the
Bus Collision Interrupt Flag (BCLIF) is set,
the START condition is aborted, and the
I2C module is reset into its IDLE state.
SCL
TBRG
S
PIC16C77X
FIGURE 8-21: START CONDITION FLOWCHART
SSPEN = 1,
SSPCON<3:0> = 1000
Idle Mode
SEN (SSPCON2<0> = 1)
Yes
No
Yes No No BRG
SCL= 0? SDA = 0? Rollover?
Yes
Yes
Reset BRG
Force SDA = 0,
Load BRG with
SSPADD<6:0>,
Set S bit.
No No BRG
SCL = 0? rollover?
Yes
Yes
Reset BRG
Force SCL = 0,
Start Condition Done,
Clear SEN
and set SSPIF
PIC16C77X
8.2.10 I2C MASTER MODE REPEATED START Immediately following the SSPIF bit getting set, the
CONDITION TIMING user may write the SSPBUF with the 7-bit address in
7-bit mode, or the default first address in 10-bit mode.
A Repeated Start condition occurs when the RSEN bit After the first eight bits are transmitted and an ACK is
(SSPCON2<1>) is programmed high and the I2C mod- received, the user may then transmit an additional eight
ule is in the idle state. When the RSEN bit is set, the bits of address (10-bit mode) or eight bits of data (7-bit
SCL pin is asserted low. When the SCL pin is sampled mode).
low, the baud rate generator is loaded with the contents
of SSPADD<6:0>, and begins counting. The SDA pin
is released (brought high) for one baud rate generator
count (TBRG). When the baud rate generator times out,
if SDA is sampled high, the SCL pin will be de-asserted 8.2.10.6 WCOL STATUS FLAG
(brought high). When SCL is sampled high the baud
If the user writes the SSPBUF when a Repeated Start
rate generator is re-loaded with the contents of
sequence is in progress, then WCOL is set and the
SSPADD<6:0> and begins counting. SDA and SCL
contents of the buffer are unchanged (the write doesnt
must be sampled high for one TBRG. This action is then
occur).
followed by assertion of the SDA pin (SDA is low) for
one TBRG while SCL is high. Following this, the RSEN Note: Because queueing of events is not
bit in the SSPCON2 register will be automatically allowed, writing of the lower 5 bits of
cleared, and the baud rate generator is not reloaded, SSPCON2 is disabled until the Repeated
leaving the SDA pin held low. As soon as a start con- Start condition is complete.
dition is detected on the SDA and SCL pins, the S bit
(SSPSTAT<3>) will be set. The SSPIF bit will not be set
until the baud rate generator has timed-out.
Note 1: If RSEN is programmed while any other
event is in progress, it will not take effect.
Note 2: A bus collision during the Repeated Start
condition occurs if:
SDA is sampled low when SCL goes from low to
high.
SCL goes low before SDA is asserted low. This
may indicate that another master is attempting
to transmit a data "1".
1st Bit
SDA
Falling edge of ninth clock Write to SSPBUF occurs here.
End of Xmit
TBRG
SCL TBRG
Sr = Repeated Start
PIC16C77X
FIGURE 8-23: REPEATED START CONDITION FLOWCHART (PAGE 1)
Start
Idle Mode,
B SSPEN = 1,
SSPCON<3:0> = 1000
RSEN = 1
Force SCL = 0
No
SCL = 0?
Yes
Release SDA,
Load BRG with
SSPADD<6:0>
BRG No
rollover?
Yes
Release SCL
(Clock Arbitration)
No
SCL = 1?
Yes
Bus Collision,
No
Set BCLIF, SDA = 1?
Release SDA,
Clear RSEN
Yes
C A
PIC16C77X
FIGURE 8-24: REPEATED START CONDITION FLOWCHART (PAGE 2)
B
C
A
Yes
No No No BRG
SCL = 1? SDA = 0? rollover?
Yes Yes
Reset BRG
Force SDA = 0,
Load BRG with
SSPADD<6:0>
Set S
No No BRG
SCL = '0'? rollover?
Yes Yes
Force SCL = 0,
Reset BRG Repeated Start
condition done,
Clear RSEN,
Set SSPIF.
PIC16C77X
8.2.11 I2C MASTER MODE TRANSMISSION 8.2.11.7 BF STATUS FLAG
Transmission of a data byte, a 7-bit address, or either In transmit mode, the BF bit (SSPSTAT<0>) is set when
half of a 10-bit address is accomplished by simply writ- the CPU writes to SSPBUF and is cleared when all 8
ing a value to SSPBUF register. This action will set the bits are shifted out.
buffer full flag (BF) and allow the baud rate generator to
begin counting and start the next transmission. Each 8.2.11.8 WCOL STATUS FLAG
bit of address/data will be shifted out onto the SDA pin
If the user writes the SSPBUF when a transmit is
after the falling edge of SCL is asserted (see data hold
already in progress (i.e. SSPSR is still shifting out a
time spec). SCL is held low for one baud rate gener-
data byte), then WCOL is set and the contents of the
ator roll over count (TBRG). Data should be valid before
buffer are unchanged (the write doesnt occur).
SCL is released high (see Data setup time spec).
When the SCL pin is released high, it is held that way WCOL must be cleared in software.
for TBRG, the data on the SDA pin must remain stable
8.2.11.9 AKSTAT STATUS FLAG
for that duration and some hold time after the next fall-
ing edge of SCL. After the eighth bit is shifted out (the In transmit mode, the AKSTAT bit (SSPCON2<6>) is
falling edge of the eighth clock), the BF flag is cleared cleared when the slave has sent an acknowledge
and the master releases SDA allowing the slave device (ACK = 0), and is set when the slave does not acknowl-
being addressed to respond with an ACK bit during the edge (ACK = 1). A slave sends an acknowledge when
ninth bit time, if an address match occurs or if data was it has recognized its address (including a general call),
received properly. The status of ACK is read into the or when the slave has properly received its data.
AKDT on the falling edge of the ninth clock. If the mas-
ter receives an acknowledge, the acknowledge status
bit (AKSTAT) is cleared. If not, the bit is set. After the
ninth clock the SSPIF is set, and the master clock
(baud rate generator) is suspended until the next data
byte is loaded into the SSPBUF leaving SCL low and
SDA unchanged (Figure 8-26).
After the write to the SSPBUF, each bit of address will
be shifted out on the falling edge of SCL until all seven
address bits and the R/W bit are completed. On the fall-
ing edge of the eighth clock the master will de-assert
the SDA pin allowing the slave to respond with an
acknowledge. On the falling edge of the ninth clock the
master will sample the SDA pin to see if the address
was recognized by a slave. The status of the ACK bit is
loaded into the AKSTAT status bit (SSPCON2<6>). Fol-
lowing the falling edge of the ninth clock transmission
of the address, the SSPIF is set, the BF flag is cleared,
and the baud rate generator is turned off until another
write to the SSPBUF takes place, holding SCL low and
allowing SDA to float.
PIC16C77X
FIGURE 8-25: MASTER TRANSMIT FLOWCHART
Idle Mode
Write SSPBUF
Num_Clocks = 0,
BF = 1
Force SCL = 0
Release SDA so
Yes
Num_Clocks slave can drive ACK,
= 8? Force BF = 0
No
Load BRG with
Load BRG with SSPADD<6:0>,
SSPADD<6:0>, start BRG count
start BRG count,
SDA = Current Data bit
BRG No
rollover?
BRG No
rollover?
Yes
Yes
Yes
Read SDA and place into
AKSTAT bit (SSPCON2<6>)
No No No
BRG SDA = Yes
rollover? SCL = 0? Data bit?
Force SCL = 0,
Yes
Set SSPIF
Yes Reset BRG
Num_Clocks
= Num_Clocks + 1
BF (SSPSTAT<0>)
Advance Information
SEN
PEN
R/W
FIGURE 8-26: I 2C MASTER MODE TIMING (TRANSMISSION, 7 OR 10-BIT ADDRESS)
DS30275B-page 81
PIC16C77X
774.book Page 82 Tuesday, January 29, 2013 12:02 PM
PIC16C77X
8.2.12 I2C MASTER MODE RECEPTION 8.2.12.10 BF STATUS FLAG
Master mode reception is enabled by programming the In receive operation, BF is set when an address or data
receive enable bit, RCEN (SSPCON2<3>). byte is loaded into SSPBUF from SSPSR. It is cleared
when SSPBUF is read.
Note: The SSP Module must be in an IDLE
STATE before the RCEN bit is set, or the 8.2.12.11 SSPOV STATUS FLAG
RCEN bit will be disregarded.
In receive operation, SSPOV is set when 8 bits are
The baud rate generator begins counting, and on each
received into the SSPSR, and the BF flag is already set
rollover, the state of the SCL pin changes (high to low/
from a previous reception.
low to high) and data is shifted into the SSPSR. After
the falling edge of the eighth clock, the receive enable 8.2.12.12 WCOL STATUS FLAG
flag is automatically cleared, the contents of the
SSPSR are loaded into the SSPBUF, the BF flag is set, If the user writes the SSPBUF when a receive is
the SSPIF is set, and the baud rate generator is sus- already in progress (i.e. SSPSR is still shifting in a data
pended from counting, holding SCL low. The SSP is byte), then WCOL is set and the contents of the buffer
now in IDLE state, awaiting the next command. When are unchanged (the write doesnt occur).
the buffer is read by the CPU, the BF flag is automati-
cally cleared. The user can then send an acknowledge
bit at the end of reception, by setting the acknowledge
sequence enable bit, AKEN (SSPCON2<4>).
PIC16C77X
FIGURE 8-27: MASTER RECEIVER FLOWCHART
Idle mode
RCEN = 1
Num_Clocks = 0,
Release SDA
Force SCL=0,
Load BRG w/
SSPADD<6:0>,
start count
BRG No
rollover?
Yes
Release SCL
(Clock Arbitration)
No
SCL = 1?
Yes
Sample SDA,
Shift data into SSPSR
BRG No No
SCL = 0?
rollover?
Yes Yes
Num_Clocks
= Num_Clocks + 1
No
Num_Clocks
= 8?
Yes
Force SCL = 0,
Set SSPIF,
Set BF.
Move contents of SSPSR
into SSPBUF,
Clear RCEN.
SEN = 0
PEN bit = 1
Write to SSPBUF occurs here RCEN cleared RCEN = 1 start RCEN cleared
ACK from Slave next receive automatically written here
Start XMIT automatically
Transmit Address to Slave R/W = 1 Receiving Data from Slave Receiving Data from Slave
SDA A7 A6 A5 A4 A3 A2 A1 ACK D7 D6 D5 D4 D3 D2 D1 D0 ACK D7 D6 D5 D4 D3 D2 D1 D0 ACK
Bus Master
ACK is not sent terminates
transfer
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
SCL S P
Data shifted in on falling edge of CLK Set SSPIF at end
of receive Set SSPIF interrupt
Set SSPIF interrupt at end of acknow-
Set SSPIF interrupt ledge sequence
at end of receive
at end of acknowledge
SSPIF sequence
Set P bit
Cleared in software Cleared in software Cleared in software Cleared in software (SSPSTAT<4>)
SDA = 0, SCL = 1 Cleared in
while CPU software and SSPIF
responds to SSPIF
Advance Information
BF
(SSPSTAT<0>) Last bit is shifted into SSPSR and
contents are unloaded into SSPBUF
SSPOV
FIGURE 8-28: I 2C MASTER MODE TIMING (RECEPTION 7-BIT ADDRESS)
AKEN
PIC16C77X
8.2.13 ACKNOWLEDGE SEQUENCE TIMING rate generator counts for TBRG . The SCL pin is then
pulled low. Following this, the AKEN bit is automati-
An acknowledge sequence is enabled by setting the cally cleared, the baud rate generator is turned off, and
acknowledge sequence enable bit, AKEN the SSP module then goes into IDLE mode. (Figure 8-
(SSPCON2<4>). When this bit is set, the SCL pin is 29)
pulled low and the contents of the acknowledge data
bit is presented on the SDA pin. If the user wishes to 8.2.13.13 WCOL STATUS FLAG
generate an acknowledge, then the AKDT bit should be
cleared. If not, the user should set the AKDT bit before If the user writes the SSPBUF when an acknowledege
starting an acknowledge sequence. The baud rate sequence is in progress, then WCOL is set and the
generator then counts for one rollover period (TBRG), contents of the buffer are unchanged (the write doesnt
and the SCL pin is de-asserted (pulled high). When the occur).
SCL pin is sampled high (clock arbitration), the baud
TBRG TBRG
SDA D0 ACK
SCL 8 9
SSPIF
PIC16C77X
FIGURE 8-30: ACKNOWLEDGE FLOWCHART
Idle mode
Set AKEN
Force SCL = 0
BRG Yes
rollover?
No
No
SCL = 0?
Yes
No BRG
rollover?
Yes
SDA = 1?
Yes
No
Force SCL = 1
Yes
PIC16C77X
8.2.14 STOP CONDITION TIMING while SCL is high, the P bit (SSPSTAT<4>) is set. A
TBRG later the PEN bit is cleared and the SSPIF bit is
A stop bit is asserted on the SDA pin at the end of a set (Figure 8-31).
receive/transmit by setting the Stop Sequence Enable
bit PEN (SSPCON2<2>). At the end of a receive/trans- Whenever the firmware decides to take control of the
mit the SCL line is held low after the falling edge of the bus, it will first determine if the bus is busy by checking
ninth clock. When the PEN bit is set, the master will the S and P bits in the SSPSTAT register. If the bus is
assert the SDA line low . When the SDA line is sam- busy, then the CPU can be interrupted (notified) when
pled low, the baud rate generator is reloaded and a Stop bit is detected (i.e. bus is free).
counts down to 0. When the baud rate generator times 8.2.14.14 WCOL STATUS FLAG
out, the SCL pin will be brought high, and one TBRG
(baud rate generator rollover count) later, the SDA pin If the user writes the SSPBUF when a STOP sequence
will be de-asserted. When the SDA pin is sampled high is in progress, then WCOL is set and the contents of the
buffer are unchanged (the write doesnt occur).
SDA ACK
P
TBRG TBRG TBRG
SCL brought high after TBRG
PIC16C77X
FIGURE 8-32: STOP CONDITION FLOWCHART
Idle Mode,
SSPEN = 1,
SSPCON<3:0> = 1000
Force SDA = 0
SCL doesnt change
BRG No
rollover?
Yes
No
SDA = 0? Release SDA,
Start BRG
Yes
Start BRG
BRG No
rollover?
BRG No Yes
rollover?
Bus Collision detected,
No
Yes P bit Set? Set BCLIF,
Clear PEN
De-assert SCL,
SCL = 1
Yes
Yes
PIC16C77X
8.2.15 CLOCK ARBITRATION 8.2.16 SLEEP OPERATION
Clock arbitration occurs when the master, during any While in sleep mode, the I2C module can receive
receive, transmit, or repeated start/stop condition, de- addresses or data, and when an address match or
asserts the SCL pin (SCL allowed to float high). When complete byte transfer occurs wake the processor from
the SCL pin is allowed to float high, the baud rate gen- sleep ( if the SSP interrupt is enabled).
erator (BRG) is suspended from counting until the SCL
pin is actually sampled high. When the SCL pin is sam- 8.2.17 EFFECTS OF A RESET
pled high, the baud rate generator is reloaded with the
A reset disables the SSP module and terminates the
contents of SSPADD<6:0> and begins counting. This
current transfer.
ensures that the SCL high time will always be at least
one BRG rollover count in the event that the clock is
held low by an external device (Figure 8-33).
SCL
SDA
PIC16C77X
8.2.18 MULTI -MASTER COMMUNICATION, BUS If a START, Repeated Start, STOP, or Acknowledge
COLLISION, AND BUS ARBITRATION condition was in progress when the bus collision
occurred, the condition is aborted, the SDA and SCL
Multi-Master mode support is achieved by bus arbitra- lines are de-asserted, and the respective control bits in
tion. When the master outputs address/data bits onto the SSPCON2 register are cleared. When the user
the SDA pin, arbitration takes place when the master services the bus collision interrupt service routine, and
outputs a '1' on SDA by letting SDA float high and if the I2C bus is free, the user can resume communica-
another master asserts a '0'. When the SCL pin floats tion by asserting a START condition.
high, data should be stable. If the expected data on
SDA is a '1' and the data sampled on the SDA pin = '0', The Master will continue to monitor the SDA and SCL
then a bus collision has taken place. The master will pins, and if a STOP condition occurs, the SSPIF bit will
set the Bus Collision Interrupt Flag, BCLIF and reset be set.
the I2C port to its IDLE state. (Figure 8-34). A write to the SSPBUF will start the transmission of
If a transmit was in progress when the bus collision data at the first data bit, regardless of where the trans-
occurred, the transmission is halted, the BF flag is mitter left off when bus collision occurred.
cleared, the SDA and SCL lines are de-asserted, and In multi-master mode, the interrupt generation on the
the SSPBUF can be written to. When the user services detection of start and stop conditions allows the deter-
the bus collision interrupt service routine, and if the I2C mination of when the bus is free. Control of the I2C bus
bus is free, the user can resume communication by can be taken when the P bit is set in the SSPSTAT reg-
asserting a START condition. ister, or the bus is idle and the S and P bits are cleared.
SDA
BCLIF
PIC16C77X
8.2.18.15 BUS COLLISION DURING A START while SDA is high, a bus collision occurs, because it is
CONDITION assumed that another master is attempting to drive a
data '1' during the START condition.
During a START condition, a bus collision occurs if:
If the SDA pin is sampled low during this count, the
a) SDA or SCL are sampled low at the beginning of BRG is reset and the SDA line is asserted early
the START condition (Figure 8-35). (Figure 8-37). If however a '1' is sampled on the SDA
b) SCL is sampled low before SDA is asserted low. pin, the SDA pin is asserted low at the end of the BRG
(Figure 8-36). count. The baud rate generator is then reloaded and
During a START condition both the SDA and the SCL counts down to 0, and during this time, if the SCL pins
pins are monitored. is sampled as '0', a bus collision does not occur. At the
end of the BRG count the SCL pin is asserted low.
If:
Note: The reason that bus collision is not a factor
the SDA pin is already low
during a START condition is that no two
or the SCL pin is already low,
bus masters can assert a START condition
then: at the exact same time. Therefore, one
the START condition is aborted, master will always assert SDA before the
and the BCLIF flag is set, other. This condition does not cause a bus
and the SSP module is reset to its IDLE state collision because the two masters must be
(Figure 8-35). allowed to arbitrate the first address follow-
ing the START condition, and if the
The START condition begins with the SDA and SCL
address is the same, arbitration must be
pins de-asserted. When the SDA pin is sampled high,
allowed to continue into the data portion,
the baud rate generator is loaded from SSPADD<6:0>
REPEATED START, or STOP conditions.
and counts down to 0. If the SCL pin is sampled low
SDA
SCL
Set SEN, enable start SEN cleared automatically because of bus collision.
condition if SDA = 1, SCL=1 SSP module reset into idle state.
SEN
SDA sampled low before
START condition. Set BCLIF.
S bit and SSPIF set because
BCLIF SDA = 0, SCL = 1
SSPIF and BCLIF are
cleared in software.
SSPIF
PIC16C77X
FIGURE 8-36: BUS COLLISION DURING START CONDITION (SCL = 0)
SDA = 0, SCL = 1
TBRG TBRG
SDA
FIGURE 8-37: BRG RESET DUE TO SDA COLLISION DURING START CONDITION
SDA = 0, SCL = 1
Set S Set SSPIF
Less than TBRG
TBRG
SCL S
SCL pulled low after BRG
Timeout
SEN
Set SEN, enable start
sequence if SDA = 1, SCL = 1
BCLIF '0'
SSPIF
SDA = 0, SCL = 1 Interrupts cleared
Set SSPIF in software.
PIC16C77X
8.2.18.16 BUS COLLISION DURING A REPEATED however SDA is sampled high then the BRG is
START CONDITION reloaded and begins counting. If SDA goes from high
to low before the BRG times out, no bus collision
During a Repeated Start condition, a bus collision occurs, because no two masters can assert SDA at
occurs if: exactly the same time.
a) A low level is sampled on SDA when SCL goes If, however, SCL goes from high to low before the BRG
from low level to high level. times out and SDA has not already been asserted, then
b) SCL goes low before SDA is asserted low, indi- a bus collision occurs. In this case, another master is
cating that another master is attempting to trans- attempting to transmit a data 1 during the Repeated
mit a data 1. Start condition.
When the user de-asserts SDA and the pin is allowed If at the end of the BRG time out both SCL and SDA are
to float high, the BRG is loaded with SSPADD<6:0>, still high, the SDA pin is driven low, the BRG is
and counts down to 0. The SCL pin is then de- reloaded, and begins counting. At the end of the count,
asserted, and when sampled high, the SDA pin is sam- regardless of the status of the SCL pin, the SCL pin is
pled. If SDA is low, a bus collision has occurred (i.e. driven low and the Repeated Start condition is com-
another master is attempting to transmit a data 0). If plete (Figure 8-38).
SDA
SCL
RSEN
BCLIF
Cleared in software
S '0' '0'
TBRG TBRG
SDA
SCL
S '0' '0'
PIC16C77X
8.2.18.17 BUS COLLISION DURING A STOP The STOP condition begins with SDA asserted low.
CONDITION When SDA is sampled low, the SCL pin is allow to float.
When the pin is sampled high (clock arbitration), the
Bus collision occurs during a STOP condition if: baud rate generator is loaded with SSPADD<6:0> and
a) After the SDA pin has been de-asserted and counts down to 0. After the BRG times out SDA is sam-
allowed to float high, SDA is sampled low after pled. If SDA is sampled low, a bus collision has
the BRG has timed out. occurred. This is due to another master attempting to
b) After the SCL pin is de-asserted, SCL is sam- drive a data '0'. If the SCL pin is sampled low before
pled low before SDA goes high. SDA is allowed to float high, a bus collision occurs.
This is another case of another master attempting to
drive a data '0' (Figure 8-40).
PEN
BCLIF
P '0' '0'
SDA
Assert SDA SCL goes low before SDA goes high
Set BCLIF
SCL
PEN
BCLIF
P '0'
SSPIF '0'
PIC16C77X
8.3 Connection Considerations for I2C example, with a supply voltage of VDD = 5V+10% and
Bus VOL max = 0.4V at 3 mA, Rp min = (5.5-0.4)/0.003 =
1.7 k VDD as a function of Rp is shown in Figure 8-42.
For standard-mode I2C bus devices, the values of The desired noise margin of 0.1VDD for the low level
resistors Rp Rs in Figure 8-42 depends on the following limits the maximum value of Rs. Series resistors are
parameters optional and used to improve ESD susceptibility.
Supply voltage The bus capacitance is the total capacitance of wire,
Bus capacitance connections, and pins. This capacitance limits the max-
Number of connected devices imum value of Rp due to the specified rise time
(input current + leakage current). (Figure 8-42).
The supply voltage limits the minimum value of resistor The SMP bit is the slew rate control enabled bit. This bit
Rp due to the specified minimum sink current of 3 mA is in the SSPSTAT register, and controls the slew rate
at VOL max = 0.4V for the specified output stages. For of the I/O pins when in I2C mode (master or slave).
Rp Rp DEVICE
Rs Rs
SDA
SCL
Cb=10 - 400 pF
NOTE: I2C devices with input levels related to VDD must have one common supply
line to which the pull up resistor is also connected.
PIC16C77X
NOTES:
PIC16C77X
9.0 ADDRESSABLE UNIVERSAL The USART can be configured in the following modes:
SYNCHRONOUS Asynchronous (full duplex)
ASYNCHRONOUS RECEIVER Synchronous - Master (half duplex)
TRANSMITTER (USART) Synchronous - Slave (half duplex)
The Universal Synchronous Asynchronous Receiver Bit SPEN (RCSTA<7>), and bits TRISC<7:6>, have to
Transmitter (USART) module is one of the two serial be set in order to configure pins RC6/TX/CK and RC7/
I/O modules. (USART is also known as a Serial Com- RX/DT as the Universal Synchronous Asynchronous
munications Interface or SCI). The USART can be con- Receiver Transmitter.
figured as a full duplex asynchronous system that can The USART module also has a multi-processor com-
communicate with peripheral devices such as CRT ter- munication capability using 9-bit address detection.
minals and personal computers, or it can be configured
as a half duplex synchronous system that can commu-
nicate with peripheral devices such as A/D or D/A inte-
grated circuits, Serial EEPROMs etc.
FIGURE 9-1: TXSTA: TRANSMIT STATUS AND CONTROL REGISTER (ADDRESS 98h)
PIC16C77X
FIGURE 9-2: RCSTA: RECEIVE STATUS AND CONTROL REGISTER (ADDRESS 18h)
PIC16C77X
9.1 USART Baud Rate Generator (BRG) EXAMPLE 9-1: CALCULATING BAUD RATE
ERROR
The BRG supports both the Asynchronous and Syn-
chronous modes of the USART. It is a dedicated 8-bit Desired Baud rate = Fosc / (64 (X + 1))
baud rate generator. The SPBRG register controls the 9600 = 16000000 /(64 (X + 1))
period of a free running 8-bit timer. In asynchronous X = 25.042 = 25
mode bit BRGH (TXSTA<2>) also controls the baud
Calculated Baud Rate=16000000 / (64 (25 + 1))
rate. In synchronous mode bit BRGH is ignored.
Table 9-1 shows the formula for computation of the = 9615
baud rate for different USART modes which only apply Error = (Calculated Baud Rate - Desired Baud Rate)
in master mode (internal clock). Desired Baud Rate
Given the desired baud rate and Fosc, the nearest inte- = (9615 - 9600) / 9600
ger value for the SPBRG register can be calculated = 0.16%
using the formula in Table 9-1. From this, the error in
baud rate can be determined.
It may be advantageous to use the high baud rate
Example 9-1 shows the calculation of the baud rate
(BRGH = 1) even for slower baud clocks. This is
error for the following conditions:
because the FOSC/(16(X + 1)) equation can reduce the
FOSC = 16 MHz baud rate error in some cases.
Desired Baud Rate = 9600
BRGH = 0 Writing a new value to the SPBRG register causes the
SYNC = 0 BRG timer to be reset (or cleared). This ensures the
BRG does not wait for a timer overflow before output-
ting the new baud rate.
9.1.1 SAMPLING
Value on:
Value on all
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR,
other resets
BOR
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 0000 -010
18h RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented read as '0'. Shaded cells are not used by the BRG.
PIC16C77X
TABLE 9-3 BAUD RATES FOR SYNCHRONOUS MODE
FOSC = 20 MHz 16 MHz 10 MHz 7.15909 MHz
BAUD SPBRG SPBRG SPBRG SPBRG
RATE % value % value % value % value
KBAUD KBAUD KBAUD KBAUD
(K) ERROR (decimal) ERROR (decimal) ERROR (decimal) ERROR (decimal)
0.3 NA - - NA - - NA - - NA - -
1.2 NA - - NA - - NA - - NA - -
2.4 NA - - NA - - NA - - NA - -
9.6 NA - - NA - - 9.766 +1.73 255 9.622 +0.23 185
19.2 19.53 +1.73 255 19.23 +0.16 207 19.23 +0.16 129 19.24 +0.23 92
76.8 76.92 +0.16 64 76.92 +0.16 51 75.76 -1.36 32 77.82 +1.32 22
96 96.15 +0.16 51 95.24 -0.79 41 96.15 +0.16 25 94.20 -1.88 18
300 294.1 -1.96 16 307.69 +2.56 12 312.5 +4.17 7 298.3 -0.57 5
500 500 0 9 500 0 7 500 0 4 NA - -
HIGH 5000 - 0 4000 - 0 2500 - 0 1789.8 - 0
LOW 19.53 - 255 15.625 - 255 9.766 - 255 6.991 - 255
FOSC = 5.0688 MHz 4 MHz 3.579545 MHz 1 MHz 32.768 kHz
BAUD SPBRG SPBRG SPBRG SPBRG SPBRG
RATE KBAUD % value KBAUD % value KBAUD % value KBAUD % value KBAUD % value
(K) ERROR (decimal) ERROR (decimal) ERROR (decimal) ERROR (decimal) ERROR (decimal)
0.3 NA - - NA - - NA - - NA - - 0.303 +1.14 26
1.2 NA - - NA - - NA - - 1.202 +0.16 207 1.170 -2.48 6
2.4 NA - - NA - - NA - - 2.404 +0.16 103 NA - -
9.6 9.6 0 131 9.615 +0.16 103 9.622 +0.23 92 9.615 +0.16 25 NA - -
19.2 19.2 0 65 19.231 +0.16 51 19.04 -0.83 46 19.24 +0.16 12 NA - -
76.8 79.2 +3.13 15 76.923 +0.16 12 74.57 -2.90 11 83.34 +8.51 2 NA - -
96 97.48 +1.54 12 1000 +4.17 9 99.43 +3.57 8 NA - - NA - -
300 316.8 +5.60 3 NA - - 298.3 -0.57 2 NA - - NA - -
500 NA - - NA - - NA - - NA - - NA - -
HIGH 1267 - 0 100 - 0 894.9 - 0 250 - 0 8.192 - 0
LOW 4.950 - 255 3.906 - 255 3.496 - 255 0.9766 - 255 0.032 - 255
PIC16C77X
TABLE 9-5 BAUD RATES FOR ASYNCHRONOUS MODE (BRGH = 1)
FOSC = 20 MHz 16 MHz 10 MHz 7.16 MHz
BAUD SPBRG SPBRG SPBRG SPBRG
RATE % value % value % value % value
(K) KBAUD ERROR (decimal) KBAUD ERROR (decimal) KBAUD ERROR (decimal) KBAUD ERROR (decimal)
9.6 9.615 +0.16 129 9.615 +0.16 103 9.615 +0.16 64 9.520 -0.83 46
19.2 19.230 +0.16 64 19.230 +0.16 51 18.939 -1.36 32 19.454 +1.32 22
38.4 37.878 -1.36 32 38.461 +0.16 25 39.062 +1.7 15 37.286 -2.90 11
57.6 56.818 -1.36 21 58.823 +2.12 16 56.818 -1.36 10 55.930 -2.90 7
115.2 113.636 -1.36 10 111.111 -3.55 8 125 +8.51 4 111.860 -2.90 3
250 250 0 4 250 0 3 NA - - NA - -
625 625 0 1 NA - - 625 0 0 NA - -
1250 1250 0 0 NA - - NA - - NA - -
FOSC = 5.068 MHz 4 MHz 3.579 MHz 1 MHz 32.768 kHz
BAUD SPBRG SPBRG SPBRG SPBRG SPBRG
RATE % value % value % value % value % value
(K) KBAUD ERROR (decimal) KBAUD ERROR (decimal) KBAUD ERROR (decimal) KBAUD ERROR (decimal) KBAUD ERROR (decimal)
9.6 9.6 0 32 NA - - 9.727 +1.32 22 8.928 -6.99 6 NA - -
19.2 18.645 -2.94 16 1.202 +0.17 207 18.643 -2.90 11 20.833 +8.51 2 NA - -
38.4 39.6 +3.12 7 2.403 +0.13 103 37.286 -2.90 5 31.25 -18.61 1 NA - -
57.6 52.8 -8.33 5 9.615 +0.16 25 55.930 -2.90 3 62.5 +8.51 0 NA - -
115.2 105.6 -8.33 2 19.231 +0.16 12 111.860 -2.90 1 NA - - NA - -
250 NA - - NA - - 223.721 -10.51 0 NA - - NA - -
625 NA - - NA - - NA - - NA - - NA - -
1250 NA - - NA - - NA - - NA - - NA - -
PIC16C77X
9.2 USART Asynchronous Mode (occurs in one TCY), the TXREG register is empty and
flag bit TXIF (PIR1<4>) is set. This interrupt can be
In this mode, the USART uses standard nonreturn-to- enabled/disabled by setting/clearing enable bit TXIE
zero (NRZ) format (one start bit, eight or nine data bits ( PIE1<4>). Flag bit TXIF will be set regardless of the
and one stop bit). The most common data format is state of enable bit TXIE and cannot be cleared in soft-
8-bits. An on-chip dedicated 8-bit baud rate generator ware. It will reset only when new data is loaded into the
can be used to derive standard baud rate frequencies TXREG register. While flag bit TXIF indicated the sta-
from the oscillator. The USART transmits and receives tus of the TXREG register, another bit TRMT
the LSb first. The USARTs transmitter and receiver are (TXSTA<1>) shows the status of the TSR register. Sta-
functionally independent but use the same data format tus bit TRMT is a read only bit which is set when the
and baud rate. The baud rate generator produces a TSR register is empty. No interrupt logic is tied to this
clock either x16 or x64 of the bit shift rate, depending bit, so the user has to poll this bit in order to determine
on bit BRGH (TXSTA<2>). Parity is not supported by if the TSR register is empty.
the hardware, but can be implemented in software (and
stored as the ninth data bit). Asynchronous mode is Note 1: The TSR register is not mapped in data
stopped during SLEEP. memory so it is not available to the user.
Asynchronous mode is selected by clearing bit SYNC Note 2: Flag bit TXIF is set when enable bit TXEN
(TXSTA<4>). is set.
The USART Asynchronous module consists of the fol- Steps to follow when setting up an Asynchronous
lowing important elements: Transmission:
Baud Rate Generator 1. Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired,
Sampling Circuit
set bit BRGH. (Section 9.1)
Asynchronous Transmitter
2. Enable the asynchronous serial port by clearing
Asynchronous Receiver bit SYNC and setting bit SPEN.
9.2.1 USART ASYNCHRONOUS TRANSMITTER 3. If interrupts are desired, then set enable bit
TXIE.
The USART transmitter block diagram is shown in 4. If 9-bit transmission is desired, then set transmit
Figure 9-3. The heart of the transmitter is the transmit bit TX9.
(serial) shift register (TSR). The shift register obtains its
5. Enable the transmission by setting bit TXEN,
data from the read/write transmit buffer, TXREG. The
which will also set bit TXIF.
TXREG register is loaded with data in software. The
TSR register is not loaded until the STOP bit has been 6. If 9-bit transmission is selected, the ninth bit
transmitted from the previous load. As soon as the should be loaded in bit TX9D.
STOP bit is transmitted, the TSR is loaded with new 7. Load data to the TXREG register (starts trans-
data from the TXREG register (if available). Once the mission).
TXREG register transfers the data to the TSR register
SPBRG
TX9
Baud Rate Generator
TX9D
PIC16C77X
FIGURE 9-4: ASYNCHRONOUS TRANSMISSION
Write to TXREG
Word 1
BRG output
(shift clock)
RC6/TX/CK (pin)
Start Bit Bit 0 Bit 1 Bit 7/8 Stop Bit
WORD 1
TXIF bit
(Transmit buffer
reg. empty flag)
WORD 1
TRMT bit
Transmit Shift Reg
(Transmit shift
reg. empty flag)
Write to TXREG
Word 1 Word 2
BRG output
(shift clock)
RC6/TX/CK (pin)
Start Bit Bit 0 Bit 1 Bit 7/8 Stop Bit Start Bit Bit 0
TXIF bit
(interrupt reg. flag) WORD 1 WORD 2
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
18h RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 0000 -010
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for Asynchronous Transmission.
Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin devices, always maintain these bits clear.
PIC16C77X
9.2.2 USART ASYNCHRONOUS RECEIVER 9.2.3 SETTING UP 9-BIT MODE WITH ADDRESS
DETECT
The receiver block diagram is shown in Figure 9-6. The
data is received on the RC7/RX/DT pin and drives the Steps to follow when setting up an Asynchronous
data recovery block. The data recovery block is actually Reception with Address Detect Enabled:
a high speed shifter operating at x16 times the baud Initialize the SPBRG register for the appropriate
rate, whereas the main receive serial shifter operates at baud rate. If a high speed baud rate is desired, set
the bit rate or at FOSC. bit BRGH.
The USART module has a special provision for multi- Enable the asynchronous serial port by clearing
processor communication. When the RX9 bit is set in bit SYNC and setting bit SPEN.
the RCSTA register, 9-bits are received and the ninth bit If interrupts are desired, then set enable bit RCIE.
is placed in the RX9D status bit of the RSTA register.
Set bit RX9 to enable 9-bit reception.
The port can be programmed such that when the stop
bit is received, the serial port interrupt will only be acti- Set ADDEN to enable address detect.
vated if the RX9D bit = 1. This feature is enabled by Enable the reception by setting enable bit CREN.
setting the ADDEN bit RCSTA<3> in the RCSTA regis- Flag bit RCIF will be set when reception is com-
ter. This feature can be used in a multi-processor sys- plete, and an interrupt will be generated if enable
tem as follows: bit RCIE was set.
A master processor intends to transmit a block of data Read the RCSTA register to get the ninth bit and
to one of many slaves. It must first send out an address determine if any error occurred during reception.
byte that identifies the target slave. An address byte is Read the 8-bit received data by reading the
identified by the RX9D bit being a 1 (instead of a 0 for RCREG register, to determine if the device is
a data byte). If the ADDEN bit is set in the slaves being addressed.
RCSTA register, all data bytes will be ignored. How- If any error occurred, clear the error by clearing
ever, if the ninth received bit is equal to a 1, indicating enable bit CREN.
that the received byte is an address, the slave will be
If the device has been addressed, clear the
interrupted and the contents of the RSR register will be
ADDEN bit to allow data bytes and address bytes
transferred into the receive buffer. This allows the slave
to be read into the receive buffer, and interrupt the
to be interrupted only by addresses, so that the slave
CPU.
can examine the received byte to see if it is addressed.
The addressed slave will then clear its ADDEN bit and
prepare to receive data bytes from the master.
When ADDEN is set, all data bytes are ignored. Fol-
lowing the STOP bit, the data will not be loaded into the
receive buffer, and no interrupt will occur. If another
byte is shifted into the RSR register, the previous data
byte will be lost.
The ADDEN bit will only take effect when the receiver
is configured in 9-bit mode.
The receiver block diagram is shown in Figure 9-6.
Once Asynchronous mode is selected, reception is
enabled by setting bit CREN (RCSTA<4>).
PIC16C77X
FIGURE 9-6: USART RECEIVE BLOCK DIAGRAM
x64 Baud Rate CLK
OERR FERR
CREN
SPBRG
64 MSb RSR register LSb
or
16 0 Start
Baud Rate Generator Stop (8) 7 1
RC7/RX/DT
Pin Buffer Data
and Control Recovery RX9
SPEN
RX9 Enable
ADDEN Load of
RX9 Receive
Buffer
ADDEN
RSR<8> 8
Interrupt RCIF
Data Bus
RCIE
Load RSR
Bit8 = 0, Data Byte Bit8 = 1, Address Byte WORD 1
RCREG
Read
RCIF
Note: This timing diagram shows a data byte followed by an address byte. The data byte is not read into the RCREG (receive buffer)
because ADDEN = 1.
PIC16C77X
FIGURE 9-8: ASYNCHRONOUS RECEPTION WITH ADDRESS BYTE FIRST
RC7/RX/DT (pin) Start Start
bit bit0 bit1 bit8 Stop bit bit0 bit8 Stop
bit bit
Load RSR
Bit8 = 1, Address Byte Bit8 = 0, Data Byte WORD 1
RCREG
Read
RCIF
Note: This timing diagram shows an address byte followed by a data byte. The data byte is not read into the RCREG (receive buffer)
because ADEN was not updated and still = 0.
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
18h RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
1Ah RCREG USART Receive Register 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 0000 -010
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for Asynchronous Reception.
Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin devices, always maintain these bits clear.
PIC16C77X
9.3 USART Synchronous Master Mode enabled/disabled by setting/clearing enable bit TXIE
(PIE1<4>). Flag bit TXIF will be set regardless of the
In Synchronous Master mode, the data is transmitted in state of enable bit TXIE and cannot be cleared in soft-
a half-duplex manner i.e. transmission and reception ware. It will reset only when new data is loaded into the
do not occur at the same time. When transmitting data, TXREG register. While flag bit TXIF indicates the status
the reception is inhibited and vice versa. Synchronous of the TXREG register, another bit TRMT (TXSTA<1>)
mode is entered by setting bit SYNC (TXSTA<4>). In shows the status of the TSR register. TRMT is a read
addition enable bit SPEN (RCSTA<7>) is set in order to only bit which is set when the TSR is empty. No inter-
configure the RC6/TX/CK and RC7/RX/DT I/O pins to rupt logic is tied to this bit, so the user has to poll this
CK (clock) and DT (data) lines respectively. The Master bit in order to determine if the TSR register is empty.
mode indicates that the processor transmits the master The TSR is not mapped in data memory so it is not
clock on the CK line. The Master mode is entered by available to the user.
setting bit CSRC (TXSTA<7>).
Steps to follow when setting up a Synchronous Master
9.3.1 USART SYNCHRONOUS MASTER Transmission:
TRANSMISSION 1. Initialize the SPBRG register for the appropriate
baud rate (Section 9.1).
The USART transmitter block diagram is shown in
Figure 9-3. The heart of the transmitter is the transmit 2. Enable the synchronous master serial port by
(serial) shift register (TSR). The shift register obtains its setting bits SYNC, SPEN, and CSRC.
data from the read/write transmit buffer register 3. If interrupts are desired, then set enable bit
TXREG. The TXREG register is loaded with data in TXIE.
software. The TSR register is not loaded until the last 4. If 9-bit transmission is desired, then set bit TX9.
bit has been transmitted from the previous load. As 5. Enable the transmission by setting bit TXEN.
soon as the last bit is transmitted, the TSR is loaded 6. If 9-bit transmission is selected, the ninth bit
with new data from the TXREG (if available). Once the should be loaded in bit TX9D.
TXREG register transfers the data to the TSR register
7. Start transmission by loading data to the
(occurs in one Tcycle), the TXREG is empty and inter-
TXREG register.
rupt bit, TXIF (PIR1<4>) is set. The interrupt can be
TABLE 9-8 REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION
Value on:
Value on all
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR,
other Resets
BOR
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
18h RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 0000 -010
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for Synchronous Master Transmission.
Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin devices, always maintain these bits clear.
PIC16C77X
FIGURE 9-9: SYNCHRONOUS TRANSMISSION
Q1 Q2 Q3Q4 Q1 Q2 Q3 Q4 Q1 Q2Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3Q4 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3Q4 Q1Q2 Q3 Q4 Q1 Q2Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4
Write to
TXREG reg
Write word1 Write word2
TXIF bit
(Interrupt flag)
TRMT
TRMT bit
'1' '1'
TXEN bit
Note: Sync master mode; SPBRG = '0'. Continuous transmission of two 8-bit words.
RC6/TX/CK pin
Write to
TXREG reg
TXIF bit
TRMT bit
TXEN bit
PIC16C77X
9.3.2 USART SYNCHRONOUS MASTER 3. Ensure bits CREN and SREN are clear.
RECEPTION 4. If interrupts are desired, then set enable bit
RCIE.
Once Synchronous mode is selected, reception is
enabled by setting either enable bit SREN (RCSTA<5>) 5. If 9-bit reception is desired, then set bit RX9.
or enable bit CREN (RCSTA<4>). Data is sampled on 6. If a single reception is required, set bit SREN.
the RC7/RX/DT pin on the falling edge of the clock. If For continuous reception set bit CREN.
enable bit SREN is set, then only a single word is 7. Interrupt flag bit RCIF will be set when reception
received. If enable bit CREN is set, the reception is is complete and an interrupt will be generated if
continuous until CREN is cleared. If both bits are set enable bit RCIE was set.
then CREN takes precedence. 8. Read the RCSTA register to get the ninth bit (if
Steps to follow when setting up a Synchronous Master enabled) and determine if any error occurred
Reception: during reception.
1. Initialize the SPBRG register for the appropriate 9. Read the 8-bit received data by reading the
baud rate. (Section 9.1) RCREG register.
2. Enable the synchronous master serial port by 10. If any error occurred, clear the error by clearing
setting bits SYNC, SPEN, and CSRC. bit CREN.
Value on:
Value on all
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR,
other Resets
BOR
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
18h RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 0000 -010
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented read as '0'. Shaded cells are not used for Synchronous Master Reception.
Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin devices, always maintain these bits clear.
RC7/RX/DT pin bit0 bit1 bit2 bit3 bit4 bit5 bit6 bit7
RC6/TX/CK pin
Write to
bit SREN
SREN bit
CREN bit '0' '0'
RCIF bit
(interrupt)
Read
RXREG
Note: Timing diagram demonstrates SYNC master mode with bit SREN = '1' and bit BRGH = '0'.
PIC16C77X
9.4 USART Synchronous Slave Mode 9.4.2 USART SYNCHRONOUS SLAVE
RECEPTION
Synchronous slave mode differs from the Master mode
in the fact that the shift clock is supplied externally at The operation of the synchronous master and slave
the RC6/TX/CK pin (instead of being supplied internally modes is identical except in the case of the SLEEP
in master mode). This allows the device to transfer or mode. Also, bit SREN is a don't care in slave mode.
receive data while in SLEEP mode. Slave mode is If receive is enabled, by setting bit CREN, prior to the
entered by clearing bit CSRC (TXSTA<7>). SLEEP instruction, then a word may be received during
SLEEP. On completely receiving the word, the RSR
9.4.1 USART SYNCHRONOUS SLAVE
register will transfer the data to the RCREG register
TRANSMIT
and if enable bit RCIE bit is set, the interrupt generated
The operation of the synchronous master and slave will wake the chip from SLEEP. If the global interrupt is
modes are identical except in the case of the SLEEP enabled, the program will branch to the interrupt vector
mode. (0004h).
If two words are written to the TXREG and then the Steps to follow when setting up a Synchronous Slave
SLEEP instruction is executed, the following will occur: Reception:
a) The first word will immediately transfer to the 1. Enable the synchronous master serial port by
TSR register and transmit. setting bits SYNC and SPEN and clearing bit
b) The second word will remain in TXREG register. CSRC.
c) Flag bit TXIF will not be set. 2. If interrupts are desired, then set enable bit
RCIE.
d) When the first word has been shifted out of TSR,
the TXREG register will transfer the second 3. If 9-bit reception is desired, then set bit RX9.
word to the TSR and flag bit TXIF will now be 4. To enable reception, set enable bit CREN.
set. 5. Flag bit RCIF will be set when reception is com-
e) If enable bit TXIE is set, the interrupt will wake plete and an interrupt will be generated, if
the chip from SLEEP and if the global interrupt enable bit RCIE was set.
is enabled, the program will branch to the inter- 6. Read the RCSTA register to get the ninth bit (if
rupt vector (0004h). enabled) and determine if any error occurred
Steps to follow when setting up a Synchronous Slave during reception.
Transmission: 7. Read the 8-bit received data by reading the
RCREG register.
1. Enable the synchronous slave serial port by set-
ting bits SYNC and SPEN and clearing bit 8. If any error occurred, clear the error by clearing
CSRC. bit CREN.
2. Clear bits CREN and SREN.
3. If interrupts are desired, then set enable bit
TXIE.
4. If 9-bit transmission is desired, then set bit TX9.
5. Enable the transmission by setting enable bit
TXEN.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
7. Start transmission by loading data to the
TXREG register.
PIC16C77X
TABLE 9-10 REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION
Value on:
Value on all
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR,
other Resets
BOR
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
18h RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 0000 -010
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented read as '0'. Shaded cells are not used for Synchronous Slave Transmission.
Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin devices, always maintain these bits clear.
Value on:
Value on all
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR,
other Resets
BOR
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
18h RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 0000 -010
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented read as '0'. Shaded cells are not used for Synchronous Slave Reception.
Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin devices, always maintain these bits clear.
PIC16C77X
NOTES:
PIC16C77X
10.0 VOLTAGE REFERENCE The source for the reference voltages comes from the
bandgap reference circuit. The bandgap circuit is ener-
MODULE AND LOW-VOLTAGE gized anytime the reference voltage is required by the
DETECT other sub-modules, and is powered down when not in
The Voltage Reference module provides reference volt- use. The control registers for this module are LVDCON
ages for the Brown-out Reset circuitry, the Low-voltage and REFCON, as shown in Figure 10-1 and
Detect circuitry and the A/D converter. Figure 10-2.
PIC16C77X
FIGURE 10-2: REFCON: VOLTAGE REFERENCE CONTROL REGISTER
PIC16C77X
10.3 Low-voltage Detect (LVD) control. This allows a user to power the module on
and off to periodically monitor the supply voltage, and
This module is used to generate an interrupt when the thus minimize total current consumption.
supply voltage falls below a specified trip voltage.
This module operates completely under software
16 to 1 MUX
RB3/AN9/LVDIN
LVD
The LVD module is enabled by setting the LVDEN bit in If the bandgap reference voltage is previously unused
the LVDCON register. The trip point voltage is the by either the brown-out circuitry or the voltage refer-
minimum supply voltage level at which the device can ence circuitry, then the bandgap circuit requires a time
operate before the LVD module asserts an interrupt. to start-up and become stable before a low voltage con-
When the supply voltage is equal to or less than the trip dition can be reliably detected. The low-voltage inter-
point, the module will generate an interrupt signal set- rupt flag is prevented from being set until the bandgap
ting interrupt flag bit LVDIF. If interrupt enable bit LVDIE has reached a stable reference voltage.
was set, then an interrupt is generated. The LVD inter- When the bandgap is stable the BGST (LVDCON<5>)
rupt can wake the device from sleep. The "trip point" bit is set indicating that the low-voltage interrupt flag bit
voltage is software programmable to any one of 16 val- is released to be set if VDD is equal to or less than the
ues, five of which are reserved (See Figure 10-1). The LVD trip point.
trip point is selected by programming the LV3:LV0 bits
(LVDCON<3:0>). 10.3.1 EXTERNAL ANALOG VOLTAGE INPUT
Note: The LVDIF bit can not be cleared until the The LVD module has an additional feature that allows
supply voltage rises above the LVD trip the user to supply the trip voltage to the module from
point. If interrupts are enabled, clear the an external source. This mode is enabled when
LVDIE bit once the first LVD interrupt LV3:LV0 = 1111. When these bits are set the compar-
occurs to prevent reentering the interrupt ator input is multiplexed from an external input pin
service routine immediately after exiting (RB3/AN9/LVDIN.
the ISR.
Once the LV bits have been programmed for the speci-
fied trip voltage, the low-voltage detect circuitry is then
enabled by setting the LVDEN (LVDCON<4>) bit.
PIC16C77X
NOTES:
PIC16C77X
11.0 ANALOG-TO-DIGITAL The A/D module has four registers. These registers
are:
CONVERTER (A/D) MODULE
A/D Result Register Low ADRESL
The analog-to-digital (A/D) converter module has six
inputs for the PIC16C773 and ten for the PIC16C774. A/D Result Register High ADRESH
A/D Control Register 0 (ADCON0)
The analog-to-digital converter (A/D) allows conver-
sion of an analog input signal to a corresponding A/D Control Register 1 (ADCON1)
12-bit digital number. The A/D module has up to 10 A device reset forces all registers to their reset state.
analog inputs, which are multiplexed into one sample This forces the A/D module to be turned off and any
and hold. The output of the sample and hold is the conversion is aborted.
input into the converter, which generates the result via
successive approximation. The analog reference volt- 11.1 Control Registers
ages are software selectable to either the devices
The ADCON0 register, shown in Figure 11-1, controls
analog positive and negative supply voltages
the operation of the A/D module. The ADCON1 regis-
(AVDD/AVSS), the voltage level on the VREF+ and
ter, shown in Figure 11-2, configures the functions of
VREF- pins, or internal voltage references if available
the port pins, the voltage reference configuration and
(VRH, VRL).
the result format. The port pins can be configured as
The A/D converter has a unique feature of being able to analog inputs or as digital I/O.
operate while the device is in SLEEP mode. To operate
The combination of the ADRESH and ADRESL regis-
in sleep, the A/D conversion clock must be derived from
ters contain the result of the A/D conversion. The reg-
the A/Ds internal RC oscillator.
ister pair is referred to as the ADRES register. When
the A/D conversion is complete, the result is loaded
into ADRES, the GO/DONE bit (ADCON0<2>) is
cleared, and the A/D interrupt flag ADIF is set. The
block diagram of the A/D module is shown in
Figure 11-3.
ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE CHS3 ADON R= Readable bit
W= Writable bit
bit7 bit 0 -n= Value at POR reset
PIC16C77X
FIGURE 11-2: ADCON1 REGISTER (ADDRESS 9Fh)
ADFM VCFG2 VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0 R= Readable bit
W= Writable bit
bit7 bit 0 U= Unimplemented bit, read as 0
-n= Value at POR reset
AN9 AN8 AN7 AN6 AN5 AN4 AN3 AN2 AN1 AN0
0000 A A A A A A A A A A
0001 A A A A A A A A A A
0010 A A A A A A A A A A
0011 A A A A A A A A A A
0100 A A A A A A A A A A
0101 A A A A A A A A A A
0110 D A A A A A A A A A
0111 D D A A A A A A A A
1000 D D D A A A A A A A
1001 D D D D A A A A A A
1010 D D D D D A A A A A
1011 D D D D D D A A A A
1100 D D D D D D D A A A
1101 D D D D D D D D A A
1110 D D D D D D D D D A
1111 D D D D D D D D D D
PIC16C77X
The value that is in the ADRESH and ADRESL regis- After the A/D module has been configured as desired.
ters are not modified for a Power-on Reset. The and the analog input channels have their correspond-
ADRESH and ADRESL registers will contain unknown ing TRIS bits selected for port inputs, the selected
data after a Power-on Reset. channel must be acquired before conversion is
After the A/D module has been configured as desired, started. The A/D conversion cycle can be initiated by
the selected channel must be acquired before the con- setting the GO/DONE bit. The A/D conversion begins,
version is started. The analog input channels must and lasts for 13TAD. The following steps should be fol-
have their corresponding TRIS bits selected as an lowed for performing an A/D conversion:
input. To determine acquisition time, see Section 11.6. 1. Configure the A/D module
After this acquisition time has elapsed the A/D conver- Configure analog pins / voltage reference /
sion can be started. The following steps should be fol- and digital I/O (ADCON1)
lowed for doing an A/D conversion: Select A/D input channel (ADCON0)
11.2 Configuring the A/D Module Select A/D conversion clock (ADCON0)
Turn on A/D module (ADCON0)
11.3 Configuring Analog Port Pins 2. Configure A/D interrupt (if required)
The ADCON1 and TRIS registers control the operation Clear ADIF bit
of the A/D port pins. The port pins that are desired as Set ADIE bit
analog inputs must have their corresponding TRIS bit Set PEIE bit
set (input). If the TRIS bit is cleared (output), the digital Set GIE bit
output level (VOH or VOL) will be converted.
3. Wait the required acquisition time (3TAD)
The A/D operation is independent of the state of the 4. Start conversion
CHS3:CHS0 bits and the TRIS bits.
Set GO/DONE bit (ADCON0)
Note 1: When reading the PORTA or PORTE reg- 5. Wait 13TAD until A/D conversion is complete, by
ister, all pins configured as analog input either:
channels will read as cleared (a low level). Polling for the GO/DONE bit to be cleared
When reading the PORTB register, all
pins configured as analog input channels OR
will read as set (a high level). Pins config- Waiting for the A/D interrupt
ured as digital inputs, will convert an ana- 6. Read A/D Result registers (ADRESH and
log input. Analog levels on a digitally ADRESL), clear ADIF if required.
configured input will not affect the conver- 7. For next conversion, go to step 1, step 2 or step
sion accuracy. 3 as required.
Note 2: Analog levels on any pin that is defined as Clearing the GO/DONE bit during a conversion will
a digital input (including the ANx pins), abort the current conversion. The ADRESH and
may cause the input buffer to consume ADRESL registers WILL be updated with the partially
current that is out of the devices specifica- completed A/D conversion value. That is, the ADRESH
tion. and ADRESL registers WILL contain the value of the
11.3.1 CONFIGURING THE REFERENCE current incomplete conversion.
VOLTAGES Note: Do not set the ADON bit and the
GO/DONE bit in the same instruction.
The VCFG bits in the ADCON1 register configure the
Doing so will cause the GO/DONE bit to be
A/D module reference inputs. The reference high
automatically cleared.
input can come from an internal reference (VRH) or
(VRL), an external reference (VREF+), or AVDD. The
low reference input can come from an internal refer-
ence (VRL), an external reference (VREF-), or AVSS. If
an external reference is chosen for the reference high
or reference low inputs, the port pin that multiplexes
the incoming external references is configured as an
analog input, regardless of the values contained in the
A/D port configuration bits (PCFG3:PCFG0).
PIC16C77X
FIGURE 11-3: A/D BLOCK DIAGRAM
CHS3:CHS0
RB3/AN9
RB2/AN8
RE2/AN7(1)
RE1/AN6(1)
VAIN RE0/AN5(1)
(Input voltage) RA5/AN4(1)
RA3/AN3/VREF+/VRH
RA2/AN2/VREF-/VRL
RA1/AN1
AVDD
RA0/AN0
VREFH VRH
(Reference VRL
voltage)
A/D VCFG2:VCFG0
Converter
VREFL
VRL
(Reference
voltage)
AVSS
VCFG2:VCFG0
Note 1: Not available on 28-pin devices.
PIC16C77X
11.4 Selecting the A/D Conversion Clock Note that these options are the same as those of the
8-bit A/D.
The A/D conversion cycle requires 13TAD: 1 TAD for set-
For correct A/D conversions, the A/D conversion clock
tling time, and 12 TAD for conversion. The source of the
(TAD) must be selected to ensure a minimum TAD time
A/D conversion clock is software selected. The four
of 1.6 s. Table 11-1 shows the resultant TAD times
possible options for TAD are:
derived from the device operating frequencies and the
2 TOSC A/D clock source selected.
8 TOSC The ADIF bit is set on the rising edge of the 14th TAD.
32 TOSC The GO/DONE bit is cleared on the falling edge of the
Internal RC oscillator 14th TAD.
TABLE 11-1 TAD vs. DEVICE OPERATING FREQUENCIES
PIC16C77X
FIGURE 11-5: FLOWCHART OF A/D OPERATION
ADON = 0
Yes
ADON = 0?
No
Sample
Selected Channel
Yes
GO = 0?
No
A/D Clock
Yes Start of A/D SLEEP Yes Finish Conversion
Conversion Delayed Instruction? GO = 0
= RC? 1 Instruction Cycle ADIF = 1
No No
No No
Wait 2 TAD
PIC16C77X
11.6 A/D Sample Requirements source impedance (RS) and the internal sampling
switch (RSS) impedance directly affect the time
11.6.1 RECOMMENDED SOURCE IMPEDANCE required to charge the capacitor CHOLD. The sampling
switch (RSS) impedance varies over the device voltage
The maximum recommended impedance for ana-
(VDD), see Figure 11-8. The maximum recom-
log sources is 2.5 k. This value is calculated based
mended impedance for analog sources is 2.5 k.
on the maximum leakage current of the input pin. The
After the analog input channel is selected (changed)
leakage current is 100 nA max., and the analog input
this sampling must be done before the conversion can
voltage cannot be vary by more than 1/4 LSb or
be started.
250 mV due to leakage. This places a requirement on
the input impedance of 250 V/100 nA = 2.5 k. To calculate the minimum sampling time,
Equation 11-6 may be used. This equation assumes
11.6.2 SAMPLING TIME CALCULATION that 1/4 LSb error is used (16384 steps for the A/D).
The 1/4 LSb error is the maximum error allowed for the
For the A/D converter to meet its specified accuracy, A/D to meet its specified resolution.
the charge holding capacitor (CHOLD) must be allowed
to fully charge to the input channel voltage level. The The CHOLD is assumed to be 25 pF for the 12-bit
analog input model is shown in Figure 11-8. The A/D.
PIC16C77X
FIGURE 11-7: CALCULATING THE MINIMUM REQUIRED SAMPLE TIME
TACQ = Amplifier Settling Time
+ Holding Capacitor Charging Time
+Temperature Coefficient
TACQ = 5 s
+ TC
+ [(Temp - 25C)(0.05s/C)]
TACQ = 5s
+ 3.3 s
+ [(50C - 25C)(0.05s / C)]
VDD
Sampling
Switch
VT = 0.6V
Rs Port Pin RIC 1k SS RSS
VSS
PIC16C77X
11.7 Use of the CCP Trigger 11.9 Faster Conversion - Lower
Resolution Trade-off
An A/D conversion can be started by the special event
trigger of the CCP module. This requires that the Not all applications require a result with 12-bits of res-
CCPnM<3:0> bits be programmed as 1011b and that olution, but may instead require a faster conversion
the A/D module is enabled (ADON is set). When the time. The A/D module allows users to make the
trigger occurs, the GO/DONE bit will be set on Q2 to trade-off of conversion speed to resolution. Regard-
start the A/D conversion and the Timer1 counter will less of the resolution required, the acquisition time is
be reset to zero. Timer1 is reset to automatically the same. To speed up the conversion, the A/D mod-
repeat the A/D conversion cycle, with minimal software ule may be halted by clearing the GO/DONE bit after
overhead (moving the ADRESH and ADRESL to the the desired number of bits in the result have been con-
desired location). The appropriate analog input chan- verted. Once the GO/DONE bit has been cleared, all
nel must be selected before the special event trigger of the remaining A/D result bits are 0. The equation
sets the GO/DONE bit (starts a conversion cycle). to determine the time before the GO/DONE bit can be
If the A/D module is not enabled (ADON is cleared), switched is as follows:
then the special event trigger will be ignored by the Conversion time = NTAD + 1TAD
A/D module, but will still reset the Timer1 counter.
Where: N = number of bits of resolution required,
11.8 Effects of a RESET and 1TAD is the amplifier settling time.
Since TAD is based from the device oscillator, the user
A device reset forces all registers to their reset state. must use some method (a timer, software loop, etc.) to
This forces the A/D module to be turned off, and any determine when the A/D GO/DONE bit may be
conversion is aborted. The value that is in the cleared. Table 11-2 shows a comparison of time
ADRESH and ADRESL registers are not modified. required for a conversion with 4-bits of resolution, ver-
The ADRESH and ADRESL registers will contain sus the normal 12-bit resolution conversion. The
unknown data after a Power-on Reset. example is for devices operating at 20 MHz. The A/D
clock is programmed for 32 TOSC.
TABLE 11-2 4-BIT vs. 12-BIT
CONVERSION TIMES
Freq. Resolution
(MHz) 4-bit 12-bit
Tosc 20 50 ns 50 ns
TAD = 32 Tosc 20 1.6 s 1.6 s
1TAD+NTAD 20 8 s 20.8 s
PIC16C77X
11.10 A/D Operation During Sleep Turning off the A/D places the A/D module in its lowest
current consumption state.
The A/D module can operate during SLEEP mode. This
requires that the A/D clock source be configured for RC Note: For the A/D module to operate in SLEEP,
(ADCS1:ADCS0 = 11b). With the RC clock source the A/D clock source must be configured to
selected, when the GO/DONE bit is set the A/D module RC (ADCS1:ADCS0 = 11b).
waits one instruction cycle before starting the conver-
11.11 Connection Considerations
sion cycle. This allows the SLEEP instruction to be exe-
cuted, which eliminates all digital switching noise Since the analog inputs employ ESD protection, they
during the sample and conversion. When the conver- have diodes to VDD and VSS. This requires that the
sion cycle is completed the GO/DONE bit is cleared, analog input must be between VDD and VSS. If the input
and the result loaded into the ADRESH and ADRESL voltage exceeds this range by greater than 0.3V (either
registers. If the A/D interrupt is enabled, the device will direction), one of the diodes becomes forward biased
wake-up from SLEEP. If the A/D interrupt is not and it may damage the device if the input current spec-
enabled, the A/D module will then be turned off, ification is exceeded.
although the ADON bit will remain set.
An external RC filter is sometimes added for anti-alias-
When the A/D clock source is another clock option (not ing of the input signal. The R component should be
RC), a SLEEP instruction causes the present conver- selected to ensure that the total source impedance is
sion to be aborted and the A/D module is turned off, kept under the 2.5 k recommended specification. Any
though the ADON bit will remain set. external components connected (via hi-impedance) to
an analog input pin (capacitor, zener diode, etc.) should
have very little leakage current at the pin.
TABLE 11-3 SUMMARY OF A/D REGISTERS
Value on:
Value on all
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 POR,
other Resets
BOR
0Bh,8Bh, INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
10Bh,18Bh
(1)
0Ch PIR1 PSPIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
1Eh ADRESH A/D High Byte Result Register xxxx xxxx uuuu uuuu
9Eh ADRESL A/D Low Byte Result Register xxxx xxxx uuuu uuuu
9Bh REFCON VRHEN VRLEN VRHOEN VRLOEN 0000 ---- 0000 ----
1Fh ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE CHS3 ADON 0000 0000 0000 0000
9Fh ADCON1 ADFM VCFG2 VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0 0000 0000 0000 0000
05h PORTA PORTA5(2) PORTA Data Latch when written: PORTA<4:0> pins when read --0x 0000 --0u 0000
06h PORTB PORTB Data Latch when written: PORTB pins when read xxxx 11xx uuuu 11uu
09h(2) PORTE RE2 RE1 RE0 ---- -000 ---- -000
85h TRISA bit5(2) PORTA Data Direction Register --11 1111 --11 1111
86h TRISB PORTB Data Direction Register 1111 1111 1111 1111
89h(2) TRISE IBF OBF IBOV PSPMODE PORTE Data Direction Bits 0000 -111 0000 -111
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used for A/D conversion.
Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin devices, always maintain these bits clear.
2: These bits/registers are not implemented on the 28-pin devices, read as '0'.
PIC16C77X
12.0 SPECIAL FEATURES OF THE Some of the core features provided may not be neces-
sary to each application that a device may be used for.
CPU The configuration word bits allow these features to be
These PICmicro devices have a host of features configured/enabled/disabled as necessary. These fea-
intended to maximize system reliability, minimize cost tures include code protection, brown-out reset and its
through elimination of external components, provide trippoint, the power-up timer, the watchdog timer and
power saving operating modes and offer code protec- the devices oscillator mode. As can be seen in
tion. These are: Figure 12-1, some additional configuration word bits
Oscillator Selection have been provided for brown-out reset trippoint selec-
tion.
Reset
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
Interrupts
Watchdog Timer (WDT)
Low-voltage detection
SLEEP
Code protection
ID locations
In-circuit serial programming
These devices have a Watchdog Timer which can be
shut off only through configuration bits. It runs off its
own RC oscillator for added reliability. There are two
timers that offer necessary delays on power-up. One is
the Oscillator Start-up Timer (OST), intended to keep
the chip in reset until the crystal oscillator is stable. The
other is the Power-up Timer (PWRT), which provides a
fixed delay of 72 ms (nominal) on power-up type resets
only (POR, BOR), designed to keep the part in reset
while the power supply stabilizes. With these two timers
on-chip, most applications need no external reset cir-
cuitry.
SLEEP mode is designed to offer a very low current
power-down mode. The user can wake-up from SLEEP
through external reset, Watchdog Timer Wake-up, or
through an interrupt. Several oscillator options are also
made available to allow the part to fit the application.
The RC oscillator option saves system cost while the
LP crystal option saves power. A set of configuration
bits are used to select various options.
Additional information on special features is available in
the PICmicro Mid-Range Reference Manual,
(DS33023).
PIC16C77X
FIGURE 12-1: CONFIGURATION WORD
CP1 CP0 BORV1 BORV0 CP1 CP0 - BODEN CP1 CP0 PWRTE WDTE FOSC1 FOSC0 Register: CONFIG
Address 2007h
bit13 12 11 10 9 8 7 6 5 4 3 2 1 bit0
(2)
bit 13-12: CP1:CP0: Code Protection bits
bit 9-8: 11 = Program memory code protection off
bit 5-4: 10 = 0800h-0FFFh code protected
01 = 0400h-0FFFh code protected
00 = 0000h-0FFFh code protected
bit 11-10: BORV1:BORV0: Brown-out Reset Voltage bits(3)
11 = VBOR set to 2.5V
10 = VBOR set to 2.7V
01 = VBOR set to 4.2V
00 = VBOR set to 4.5V
bit 7: Unimplemented, Read as '1'
bit 6: BODEN: Brown-out Reset Enable bit (1)
1 = Brown-out Reset enabled
0 = Brown-out Reset disabled
bit 3: PWRTE: Power-up Timer Enable bit (1)
1 = PWRT disabled
0 = PWRT enabled
bit 2: WDTE: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled
bit 1-0: FOSC1:FOSC0: Oscillator Selection bits
11 = RC oscillator
10 = HS oscillator
01 = XT oscillator
00 = LP oscillator
Note 1: Enabling Brown-out Reset automatically enables the Power-up Timer (PWRT) regardless of the value of bit PWRTE.
Ensure the Power-up Timer is enabled anytime Brown-out Reset is enabled.
2: All of the CP1:CP0 pairs have to be given the same value to enable the code protection scheme listed.
3: These are the minimum trip points for the BOR, see Table 15-4 for the trip point tolerances. Selection of an unused
setting may result in an inadvertant interrupt.
PIC16C77X
FIGURE 12-2: CRYSTAL/CERAMIC TABLE 12-2 CAPACITOR SELECTION FOR
RESONATOR OPERATION CRYSTAL OSCILLATOR
(HS, XT OR LP
Crystal Cap. Range Cap. Range
OSC CONFIGURATION) Osc Type
Freq C1 C2
C1(1) OSC1 LP 32 kHz 33 pF 33 pF
To 200 kHz 15 pF 15 pF
internal XT 200 kHz 47-68 pF 47-68 pF
XTAL logic
RF(3) 1 MHz 15 pF 15 pF
OSC2
SLEEP 4 MHz 15 pF 15 pF
RS(2) HS 4 MHz 15 pF 15 pF
C2 (1) PIC16C77X
8 MHz 15-33 pF 15-33 pF
Note1: See Table 12-1 and Table 12-2 for recom- 20 MHz 15-33 pF 15-33 pF
mended values of C1 and C2. These values are for design guidance only. See
2: A series resistor (RS) may be required for notes at bottom of page.
AT strip cut crystals. Crystals Used
3: RF varies with the crystal chosen. 32 kHz Epson C-001R32.768K-A 20 PPM
200 kHz STD XTL 200.000KHz 20 PPM
FIGURE 12-3: EXTERNAL CLOCK INPUT 1 MHz ECS ECS-10-13-1 50 PPM
OPERATION (HS OSC 4 MHz ECS ECS-40-20-1 50 PPM
CONFIGURATION) 8 MHz EPSON CA-301 8.000M-C 30 PPM
20 MHz EPSON CA-301 20.000M-C 30 PPM
PIC16C77X
12.2.3 RC OSCILLATOR
VDD
Rext
Internal
OSC1
clock
Cext PIC16C77X
VSS
OSC2/CLKOUT
Fosc/4
PIC16C77X
12.3 Reset Some registers are not affected in any reset condition.
Their status is unknown on a power-up reset and
The PIC16C77X devices have several different resets. unchanged in any other reset. Most other registers are
These resets are grouped into two classifications; placed into an initialized state upon reset, however they
power-up and non-power-up. The power-up type resets are not affected by a WDT reset during sleep because
are the power-on and brown-out resets which assume this is considered a WDT Wakeup, which is viewed as
the device VDD was below its normal operating range the resumption of normal operation.
for the devices configuration. The non-power up type
Several status bits have been provided to indicate
resets assume normal operating limits were main-
which reset occurred (see Table 12-4). See Table 12-6
tained before/during and after the reset.
for a full description of reset states of all registers.
Power-on Reset (POR)
A simplified block diagram of the on-chip reset circuit is
Brown-out Reset (BOR) shown in Figure 12-5.
MCLR reset during normal operation
These devices have a MCLR noise filter in the MCLR
MCLR reset during SLEEP reset path. The filter will detect and ignore small pulses.
WDT Reset (during normal operation)
It should be noted that a WDT Reset does not drive
MCLR pin low.
MCLR
SLEEP
WDT WDT
Module Time-out
Reset
VDD rise
detect
Power-on Reset
VDD
Brown-out
Reset S
BODEN
OST/PWRT
OST
Chip_Reset
10-bit Ripple counter R Q
OSC1
(1) PWRT
On-chip
RC OSC 10-bit Ripple counter
Enable PWRT
Enable OST
Note 1: This is a separate oscillator from the RC oscillator of the CLKIN pin.
PIC16C77X
12.4 Power-On Reset (POR) 12.5 Power-up Timer (PWRT)
A Power-on Reset pulse is generated on-chip when The Power-up Timer provides a fixed 72 ms nominal
VDD rise is detected (in the range of 1.5V - 2.1V). To time-out on power-up type resets only. For a POR, the
take advantage of the POR, just tie the MCLR pin PWRT is invoked when the POR pulse is generated.
directly (or through a resistor) to VDD. This will elimi- For a BOR, the PWRT is invoked when the device exits
nate external RC components usually needed to create the reset condition (VDD rises above BOR trippoint).
a Power-on Reset. A maximum rise time for VDD is The Power-up Timer operates on an internal RC oscil-
specified. See Electrical Specifications for details. For lator. The chip is kept in reset as long as the PWRT is
a slow rise time, see Figure 12-6. active. The PWRTs time delay is designed to allow VDD
Two delay timers have been provided which hold the to rise to an acceptable level. A configuration bit is pro-
device in reset after a POR (dependant upon device vided to enable/disable the PWRT for the POR only. For
configuration) so that all operational parameters have a BOR the PWRT is always available regardless of the
been met prior to releasing to device to resume/begin configuration bit setting.
normal operation. The power-up time delay will vary from chip to chip due
When the device starts normal operation (exits the to VDD, temperature, and process variation. See DC
reset condition), device operating parameters (voltage, parameters for details.
frequency, temperature,...) must be met to ensure oper-
12.6 Oscillator Start-up Timer (OST)
ation. If these conditions are not met, the device must
be held in reset until the operating conditions are met. The Oscillator Start-up Timer (OST) provides 1024
Brown-out Reset may be used to meet the startup con- oscillator cycle (from OSC1 input) delay after the
ditions, or if necessary an external POR circuit may be PWRT delay is over. This ensures that the crystal oscil-
implemented to delay end of reset for as long as lator or resonator has started and stabilized.
needed.
The OST time-out is invoked only for XT, LP and HS
modes and only on a power-up type reset or a wake-up
FIGURE 12-6: EXTERNAL POWER-ON from SLEEP.
RESET CIRCUIT (FOR SLOW
VDD POWER-UP) 12.7 Brown-Out Reset (BOR)
The Brown-out Reset module is used to generate a
VDD reset when the supply voltage falls below a specified
trip voltage. The trip voltage is configurable to any one
D R of four voltages provided by the BORV1:BORV0 config-
R1 uration word bits.
MCLR
Configuration bit, BODEN, can disable (if clear/pro-
C PIC16C77X grammed) or enable (if set) the Brown-out Reset cir-
cuitry. If VDD falls below the specified trippoint for
greater than parameter #35 in the electrical specifica-
Note 1: External Power-on Reset circuit is required tions section, the brown-out situation will reset the chip.
only if VDD power-up slope is too slow. The A reset may not occur if VDD falls below the trippoint for
diode D helps discharge the capacitor less than parameter #35. The chip will remain in Brown-
quickly when VDD powers down. out Reset until VDD rises above BVDD. The Power-up
2: R < 40 k is recommended to make sure Timer will be invoked at that point and will keep the chip
that voltage drop across R does not violate in RESET an additional 72 ms. If VDD drops below
the devices electrical specification. BVDD while the Power-up Timer is running, the chip will
go back into a Brown-out Reset and the Power-up
3: R1 = 100 to 1 k will limit any current Timer will be re-initialized. Once VDD rises above
flowing into MCLR from external capacitor BVDD, the Power-up Timer will again begin a 72 ms
C in the event of MCLR/VPP pin break- time delay. Even though the PWRT is always enabled
down due to Electrostatic Discharge when brown-out is enabled, the PWRT configuration
(ESD) or Electrical Overstress (EOS). word bit should be cleared (enabled) when brown-out is
enabled.
PIC16C77X
12.8 Time-out Sequence Table 12-5 shows the reset conditions for some special
function registers, while Table 12-6 shows the reset
On power-up the time-out sequence is as follows: First conditions for all the registers.
PWRT time-out is invoked by the POR pulse. When the
PWRT delay expires the Oscillator Start-up Timer is 12.9 Power Control/Status Register
activated. The total time-out will vary based on oscilla- (PCON)
tor configuration and the status of the PWRT. For exam-
ple, in RC mode with the PWRT disabled, there will be The Power Control/Status Register, PCON has two sta-
no time-out at all. Figure 12-7, Figure 12-8, Figure 12- tus bits that provide indication of which power-up type
9 and Figure 12-10 depict time-out sequences on reset occurred.
power-up. Bit0 is Brown-out Reset Status bit, BOR. Bit BOR is set
Since the time-outs occur from the POR pulse, if MCLR on a Power-on Reset. It must then be set by the user
is kept low long enough, the time-outs will expire. Then and checked on subsequent resets to see if bit BOR
bringing MCLR high will begin execution immediately cleared, indicating a BOR occurred. However, if the
(Figure 12-9). This is useful for testing purposes or to brown-out circuitry is disabled, the BOR bit is a "Dont
synchronize more than one PICmicro microcontroller Care" bit and is considered unknown upon a POR.
operating in parallel. Bit1 is POR (Power-on Reset Status bit). It is cleared on
a Power-on Reset and unaffected otherwise. The user
must set this bit following a Power-on Reset.
TABLE 12-3 TIME-OUT IN VARIOUS SITUATIONS
Power-up Wake-up from
Oscillator Configuration Brown-out SLEEP
PWRTE = 0 PWRTE = 1
XT, HS, LP 72 ms + 1024TOSC 1024TOSC 72 ms + 1024TOSC 1024TOSC
RC 72 ms 72 ms
POR BOR TO PD
0 1 1 1 Power-on Reset
0 x 0 x Illegal, TO is set on POR
0 x x 0 Illegal, PD is set on POR
1 0 1 1 Brown-out Reset
1 1 0 1 WDT Reset
1 1 0 0 WDT Wake-up
1 1 u u MCLR Reset during normal operation
1 1 1 0 MCLR Reset during SLEEP or interrupt wake-up from SLEEP
PIC16C77X
TABLE 12-6 INITIALIZATION CONDITIONS FOR ALL REGISTERS
Register Devices Power-on Reset, MCLR Resets Wake-up via WDT or
Brown-out Reset WDT Reset Interrupt
W 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
INDF 773 774 N/A N/A N/A
TMR0 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
PCL 773 774 0000h 0000h PC + 1(2)
STATUS 773 774 0001 1xxx 000q quuu(3) uuuq quuu(3)
FSR 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
PORTA 773 774 --0x 0000 --0u 0000 --uu uuuu
PORTB 773 774 xxxx 11xx uuuu 11uu uuuu uuuu
PORTC 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
PORTD 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
PORTE 773 774 ---- -000 ---- -000 ---- -uuu
PCLATH 773 774 ---0 0000 ---0 0000 ---u uuuu
INTCON 773 774 0000 000x 0000 000u uuuu uuuu(1)
PIR1 773 774 r000 0000 r000 0000 ruuu uuuu(1)
773 774 0000 0000 0000 0000 uuuu uuuu(1)
PIR2 773 774 0--- 0--0 0--- 0--0 u--- u--u(1)
TMR1L 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
TMR1H 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
T1CON 773 774 --00 0000 --uu uuuu --uu uuuu
TMR2 773 774 0000 0000 0000 0000 uuuu uuuu
T2CON 773 774 -000 0000 -000 0000 -uuu uuuu
SSPBUF 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
SSPCON 773 774 0000 0000 0000 0000 uuuu uuuu
CCPR1L 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
CCPR1H 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
CCP1CON 773 774 --00 0000 --00 0000 --uu uuuu
RCSTA 773 774 0000 000x 0000 000x uuuu uuuu
TXREG 773 774 0000 0000 0000 0000 uuuu uuuu
RCREG 773 774 0000 0000 0000 0000 uuuu uuuu
CCPR2L 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
CCPR2H 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
CCP2CON 773 774 --00 0000 --00 0000 --uu uuuu
ADRESH 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
ADCON0 773 774 0000 0000 0000 0000 uuuu uuuu
OPTION_REG 773 774 1111 1111 1111 1111 uuuu uuuu
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends
on condition
Note 1: One or more bits in INTCON, PIR1 and/or PIR2 will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the
interrupt vector (0004h).
3: See Table 12-5 for reset value for specific condition.
PIC16C77X
TABLE 12-6 INITIALIZATION CONDITIONS FOR ALL REGISTERS (Cont.d)
Register Devices Power-on Reset, MCLR Resets Wake-up via WDT or
Brown-out Reset WDT Reset Interrupt
773 774 ---1 1111 ---1 1111 ---u uuuu
TRISA
773 774 --11 1111 --11 1111 --uu uuuu
TRISB 773 774 1111 1111 1111 1111 uuuu uuuu
TRISC 773 774 1111 1111 1111 1111 uuuu uuuu
TRISD 773 774 1111 1111 1111 1111 uuuu uuuu
TRISE 773 774 0000 -111 0000 -111 uuuu -uuu
PIE1 773 774 r000 0000 r000 0000 ruuu uuuu
773 774 0000 0000 0000 0000 uuuu uuuu
PIE2 773 774 0--- 0--0 0--- 0--0 u--- u--u
PCON 773 774 ---- --qq ---- --uu ---- --uu
PR2 773 774 1111 1111 1111 1111 1111 1111
SSPADD 773 774 0000 0000 0000 0000 uuuu uuuu
SSPSTAT 773 774 0000 0000 0000 0000 uuuu uuuu
TXSTA 773 774 0000 -010 0000 -010 uuuu -uuu
SPBRG 773 774 0000 0000 0000 0000 uuuu uuuu
REFCON 773 774 0000 ---- 0000 ---- uuuu ----
LVDCON 773 774 --00 0101 --00 0101 --uu uuuu
ADRESL 773 774 xxxx xxxx uuuu uuuu uuuu uuuu
ADCON1 773 774 0000 000 0000 0000 uuuu uuuu
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends
on condition
Note 1: One or more bits in INTCON, PIR1 and/or PIR2 will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the
interrupt vector (0004h).
3: See Table 12-5 for reset value for specific condition.
VDD
MCLR
INTERNAL POR
TPWRT
OST TIME-OUT
INTERNAL RESET
PIC16C77X
FIGURE 12-8: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
VDD
MCLR
INTERNAL POR
TPWRT
OST TIME-OUT
INTERNAL RESET
FIGURE 12-9: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2
VDD
MCLR
INTERNAL POR
TPWRT
OST TIME-OUT
INTERNAL RESET
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
PIC16C77X
12.10 Interrupts The RB0/INT pin interrupt, the RB port change interrupt
and the TMR0 overflow interrupt flags are contained in
The PIC16C77X family has up to 14 sources of inter- the INTCON register.
rupt. The interrupt control register (INTCON) records
The peripheral interrupt flags are contained in the spe-
individual interrupt requests in flag bits. It also has indi-
cial function registers PIR1 and PIR2. The correspond-
vidual and global interrupt enable bits.
ing interrupt enable bits are contained in special
Note: Individual interrupt flag bits are set regard- function registers PIE1 and PIE2, and the peripheral
less of the status of their corresponding interrupt enable bit is contained in special function reg-
mask bit or the GIE bit. ister INTCON.
A global interrupt enable bit, GIE (INTCON<7>) When an interrupt is responded to, the GIE bit is
enables (if set) all un-masked interrupts or disables (if cleared to disable any further interrupt, the return
cleared) all interrupts. When bit GIE is enabled, and an address is pushed onto the stack and the PC is loaded
interrupts flag bit and mask bit are set, the interrupt will with 0004h. Once in the interrupt service routine the
vector immediately. Individual interrupts can be dis- source(s) of the interrupt can be determined by polling
abled through their corresponding enable bits in vari- the interrupt flag bits. The interrupt flag bit(s) must be
ous registers. Individual interrupt bits are set cleared in software before re-enabling interrupts to
regardless of the status of the GIE bit. The GIE bit is avoid recursive interrupts.
cleared on reset. For external interrupt events, such as the INT pin or
The return from interrupt instruction, RETFIE, exits PORTB change interrupt, the interrupt latency will be
the interrupt routine as well as sets the GIE bit, which three or four instruction cycles. The exact latency
re-enables interrupts. depends when the interrupt event occurs. The latency
is the same for one or two cycle instructions. Individual
interrupt flag bits are set regardless of the status of
their corresponding mask bit or the GIE bit
PSPIF
PSPIE
ADIF Wake-up (If in SLEEP mode)
T0IF
ADIE T0IE
RCIF INTF
RCIE INTE
Interrupt to CPU
TXIF RBIF
TXIE RBIE
SSPIF
SSPIE
PEIE
CCP1IF
CCP1IE GIE
TMR2IF
TMR2IE
TMR1IF
TMR1IE
CCP2IF
CCP2IE
BCLIF
BCLIE
PIC16C77X
12.10.1 INT INTERRUPT 12.10.3 PORTB INTCON CHANGE
External interrupt on RB0/INT pin is edge triggered: An input change on PORTB<7:4> sets flag bit RBIF
either rising if bit INTEDG (OPTION_REG<6>) is set, (INTCON<0>). The interrupt can be enabled/disabled
or falling, if the INTEDG bit is clear. When a valid edge by setting/clearing enable bit RBIE (INTCON<4>).
appears on the RB0/INT pin, flag bit INTF (Section 3.2)
(INTCON<1>) is set. This interrupt can be disabled by
clearing enable bit INTE (INTCON<4>). Flag bit INTF 12.11 Context Saving During Interrupts
must be cleared in software in the interrupt service rou-
During an interrupt, only the return PC value is saved
tine before re-enabling this interrupt. The INT interrupt
on the stack. Typically, users may wish to save key reg-
can wake-up the processor from SLEEP, if bit INTE was
isters during an interrupt, i.e., W register and STATUS
set prior to going into SLEEP. The status of global inter-
register. This will have to be implemented in software.
rupt enable bit GIE decides whether or not the proces-
sor branches to the interrupt vector following wake-up. Example 12-1 stores and restores the W and STATUS
See Section 12.13 for details on SLEEP mode. registers. The register, W_TEMP, must be defined in
each bank and must be defined at the same offset from
12.10.2 TMR0 INTERRUPT the bank base address (i.e., if W_TEMP is defined at
0x20 in bank 0, it must also be defined at 0xA0 in bank
An overflow (FFh 00h) in the TMR0 register will set
1).
flag bit T0IF (INTCON<2>). The interrupt can be
enabled/disabled by setting/clearing enable bit T0IE The example:
(INTCON<5>). (Section 4.0) a) Stores the W register.
b) Stores the STATUS register in bank 0.
c) Stores the PCLATH register.
d) Executes the interrupt service routine code
(User-generated).
e) Restores the STATUS register (and bank select
bit).
f) Restores the W and PCLATH registers.
PIC16C77X
12.12 Watchdog Timer (WDT) The WDT can be permanently disabled by clearing
configuration bit WDTE (Section 12.1).
The Watchdog Timer is as a free running on-chip RC
WDT time-out period values may be found in the Elec-
oscillator which does not require any external compo-
trical Specifications section under parameter #31. Val-
nents. This RC oscillator is separate from the RC oscil-
ues for the WDT prescaler may be assigned using the
lator of the OSC1/CLKIN pin. That means that the WDT
OPTION_REG register.
will run, even if the clock on the OSC1/CLKIN and
OSC2/CLKOUT pins of the device has been stopped, Note: The CLRWDT and SLEEP instructions clear
for example, by execution of a SLEEP instruction. the WDT and the postscaler, if assigned to
During normal operation, a WDT time-out generates a the WDT, and prevent it from timing out and
device RESET (Watchdog Timer Reset). If the device is generating a device RESET condition.
in SLEEP mode, a WDT time-out causes the device to .
wake-up and continue with normal operation (Watch-
dog Timer Wake-up). The TO bit in the STATUS register Note: When a CLRWDT instruction is executed
will be cleared upon a Watchdog Timer time-out. and the prescaler is assigned to the WDT,
the prescaler count will be cleared, but the
prescaler assignment is not changed.
0
M Postscaler
1 U
WDT Timer
X 8
8 - to - 1 MUX PS2:PS0
PSA
WDT
Enable Bit
To TMR0 (Section 4-2)
0 1
MUX PSA
WDT
Note: PSA and PS2:PS0 are bits in the OPTION_REG register. Time-out
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
2007h Config. bits (1) BODEN(1) CP1 CP0 PWRTE(1) WDTE FOSC1 FOSC0
81h,181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0
Legend: Shaded cells are not used by the Watchdog Timer.
Note 1: See Figure 12-1 for the full description of the configuration word bits.
PIC16C77X
12.13 Power-down Mode (SLEEP) Other peripherals cannot generate interrupts since dur-
ing SLEEP, no on-chip clocks are present.
Power-down mode is entered by executing a SLEEP
When the SLEEP instruction is being executed, the next
instruction.
instruction (PC + 1) is pre-fetched. For the device to
If enabled, the Watchdog Timer will be cleared but wake-up through an interrupt event, the corresponding
keeps running, the PD bit (STATUS<3>) is cleared, the interrupt enable bit must be set (enabled). Wake-up is
TO (STATUS<4>) bit is set, and the oscillator driver is regardless of the state of the GIE bit. If the GIE bit is
turned off. The I/O ports maintain the status they had, clear (disabled), the device continues execution at the
before the SLEEP instruction was executed (driving instruction after the SLEEP instruction. If the GIE bit is
high, low, or hi-impedance). set (enabled), the device executes the instruction after
For lowest current consumption in this mode, place all the SLEEP instruction and then branches to the inter-
I/O pins at either VDD, or VSS, ensure no external cir- rupt address (0004h). In cases where the execution of
cuitry is drawing current from the I/O pin, power-down the instruction following SLEEP is not desirable, the
the A/D, disable external clocks. Pull all I/O pins, that user should have a NOP after the SLEEP instruction.
are hi-impedance inputs, high or low externally to avoid
12.13.2 WAKE-UP USING INTERRUPTS
switching currents caused by floating inputs. The
T0CKI input should also be at VDD or VSS for lowest When global interrupts are disabled (GIE cleared) and
current consumption. The contribution from on-chip any interrupt source has both its interrupt enable bit
pull-ups on PORTB should be considered. and interrupt flag bit set, one of the following will occur:
The MCLR pin must be at a logic high level (VIHMC). If the interrupt occurs before the execution of a
SLEEP instruction, the SLEEP instruction will com-
12.13.1 WAKE-UP FROM SLEEP
plete as a NOP. Therefore, the WDT and WDT
The device can wake up from SLEEP through one of postscaler will not be cleared, the TO bit will not
the following events: be set and PD bits will not be cleared.
1. External reset input on MCLR pin. If the interrupt occurs during or after the execu-
tion of a SLEEP instruction, the device will imme-
2. Watchdog Timer Wake-up (if WDT was
diately wake up from sleep. The SLEEP instruction
enabled).
will be completely executed before the wake-up.
3. Interrupt from INT pin, RB port change, or some Therefore, the WDT and WDT postscaler will be
Peripheral Interrupts. cleared, the TO bit will be set and the PD bit will
External MCLR Reset will cause a device reset. All be cleared.
other events are considered a continuation of program Even if the flag bits were checked before executing a
execution and cause a "wake-up". The TO and PD bits SLEEP instruction, it may be possible for flag bits to
in the STATUS register can be used to determine the become set before the SLEEP instruction completes. To
cause of device reset. The PD bit, which is set on determine whether a SLEEP instruction executed, test
power-up, is cleared when SLEEP is invoked. The TO the PD bit. If the PD bit is set, the SLEEP instruction
bit is cleared if a WDT time-out occurred (and caused was executed as a NOP.
wake-up).
To ensure that the WDT is cleared, a CLRWDT instruc-
The following peripheral interrupts can wake the device tion should be executed before a SLEEP instruction.
from SLEEP:
1. PSP read or write.
2. TMR1 interrupt. Timer1 must be operating as
an asynchronous counter.
3. CCP capture mode interrupt.
4. Special event trigger (Timer1 in asynchronous
mode using an external clock).
5. SSP (Start/Stop) bit detect interrupt.
6. SSP transmit or receive in slave mode (SPI/I2C).
7. USART RX or TX (synchronous slave mode).
8. A/D conversion (when A/D clock source is RC).
9. Low-voltage detect.
PIC16C77X
FIGURE 12-14: WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
CLKOUT(4) TOST(2)
INT pin
INTF flag
(INTCON<1>) Interrupt Latency
(Note 2)
GIE bit Processor in
(INTCON<7>)
SLEEP
INSTRUCTION FLOW
PC PC PC+1 PC+2 PC+2 PC + 2 0004h 0005h
Instruction
fetched Inst(PC) = SLEEP Inst(PC + 1) Inst(PC + 2) Inst(0004h) Inst(0005h)
PIC16C77X
NOTES:
PIC16C77X
13.0 INSTRUCTION SET SUMMARY Table 13-2 lists the instructions recognized by the
MPASM assembler.
Each PIC16CXXX instruction is a 14-bit word divided
into an OPCODE which specifies the instruction type Figure 13-1 shows the general formats that the instruc-
and one or more operands which further specify the tions can have.
operation of the instruction. The PIC16CXX instruction Note: To maintain upward compatibility with
set summary in Table 13-2 lists byte-oriented, bit-ori- future PIC16CXXX products, do not use
ented, and literal and control operations. Table 13-1 the OPTION and TRIS instructions.
shows the opcode field descriptions.
All examples use the following format to represent a
For byte-oriented instructions, 'f' represents a file reg-
hexadecimal number:
ister designator and 'd' represents a destination desig-
nator. The file register designator specifies which file 0xhh
register is to be used by the instruction. where h signifies a hexadecimal digit.
The destination designator specifies where the result of
the operation is to be placed. If 'd' is zero, the result is FIGURE 13-1: GENERAL FORMAT FOR
placed in the W register. If 'd' is one, the result is placed INSTRUCTIONS
in the file register specified in the instruction. Byte-oriented file register operations
For bit-oriented instructions, 'b' represents a bit field 13 8 7 6 0
designator which selects the number of the bit affected OPCODE d f (FILE #)
by the operation, while 'f' represents the number of the d = 0 for destination W
file in which the bit is located. d = 1 for destination f
f = 7-bit file register address
For literal and control operations, 'k' represents an
eight or eleven bit constant or literal value.
Bit-oriented file register operations
TABLE 13-1 OPCODE FIELD 13 10 9 7 6 0
DESCRIPTIONS OPCODE b (BIT #) f (FILE #)
PIC16C77X
TABLE 13-2 PIC16CXXX INSTRUCTION SET
Mnemonic, Description Cycles 14-Bit Opcode Status Notes
Operands Affected
MSb LSb
PIC16C77X
14.0 DEVELOPMENT SUPPORT 14.3 ICEPIC: Low-Cost PICmicro
In-Circuit Emulator
14.1 Development Tools
ICEPIC is a low-cost in-circuit emulator solution for the
The PICmicro microcontrollers are supported with a Microchip PIC12CXXX, PIC16C5X and PIC16CXXX
full range of hardware and software development tools: families of 8-bit OTP microcontrollers.
MPLAB -ICEReal-Time In-Circuit Emulator ICEPIC is designed to operate on PC-compatible
ICEPIC Low-Cost PIC16C5X and PIC16CXXX machines ranging from 386 through Pentium based
In-Circuit Emulator machines under Windows 3.x, Windows 95, or Win-
PRO MATE II Universal Programmer dows NT environment. ICEPIC features real time, non-
intrusive emulation.
PICSTART Plus Entry-Level Prototype
Programmer 14.4 PRO MATE II: Universal Programmer
SIMICE
PICDEM-1 Low-Cost Demonstration Board The PRO MATE II Universal Programmer is a full-fea-
tured programmer capable of operating in stand-alone
PICDEM-2 Low-Cost Demonstration Board
mode as well as PC-hosted mode. PRO MATE II is CE
PICDEM-3 Low-Cost Demonstration Board compliant.
MPASM Assembler
The PRO MATE II has programmable VDD and VPP
MPLABSIM Software Simulator supplies which allows it to verify programmed memory
MPLAB-C17 (C Compiler) at VDD min and VDD max for maximum reliability. It has
Fuzzy Logic Development System an LCD display for displaying error messages, keys to
(fuzzyTECHMP) enter commands and a modular detachable socket
KEELOQ Evaluation Kits and Programmer assembly to support various package types. In stand-
alone mode the PRO MATE II can read, verify or pro-
14.2 MPLAB-ICE: High Performance gram PIC12CXXX, PIC14C000, PIC16C5X,
Universal In-Circuit Emulator with PIC16CXXX and PIC17CXX devices. It can also set
MPLAB IDE configuration and code-protect bits in this mode.
The MPLAB-ICE Universal In-Circuit Emulator is 14.5 PICSTART Plus Entry Level
intended to provide the product development engineer Development System
with a complete microcontroller design tool set for
PICmicro microcontrollers (MCUs). MPLAB-ICE is sup- The PICSTART programmer is an easy-to-use, low-
plied with the MPLAB Integrated Development Environ- cost prototype programmer. It connects to the PC via
ment (IDE), which allows editing, make and one of the COM (RS-232) ports. MPLAB Integrated
download, and source debugging from a single envi- Development Environment software makes using the
ronment. programmer simple and efficient. PICSTART Plus is not
recommended for production programming.
Interchangeable processor modules allow the system
to be easily reconfigured for emulation of different pro- PICSTART Plus supports all PIC12CXXX, PIC14C000,
cessors. The universal architecture of the MPLAB-ICE PIC16C5X, PIC16CXXX and PIC17CXX devices with
allows expansion to support all new Microchip micro- up to 40 pins. Larger pin count devices such as the
controllers. PIC16C923, PIC16C924 and PIC17C756 may be sup-
ported with an adapter socket. PICSTART Plus is CE
The MPLAB-ICE Emulator System has been designed compliant.
as a real-time emulation system with advanced fea-
tures that are generally found on more expensive devel-
opment tools. The PC compatible 386 (and higher)
machine platform and Microsoft Windows 3.x or
Windows 95 environment were chosen to best make
these features available to you, the end user.
MPLAB-ICE is available in two versions.
MPLAB-ICE 1000 is a basic, low-cost emulator system
with simple trace capabilities. It shares processor mod-
ules with the MPLAB-ICE 2000. This is a full-featured
emulator system with enhanced trace, trigger, and data
monitoring features. Both systems will operate across
the entire operating speed reange of the PICmicro
MCU.
PIC16C77X
14.6 SIMICE Entry-Level Hardware 14.8 PICDEM-2 Low-Cost PIC16CXX
Simulator Demonstration Board
SIMICE is an entry-level hardware development sys- The PICDEM-2 is a simple demonstration board that
tem designed to operate in a PC-based environment supports the PIC16C62, PIC16C64, PIC16C65,
with Microchips simulator MPLAB-SIM. Both SIM- PIC16C73 and PIC16C74 microcontrollers. All the
ICE and MPLAB-SIM run under Microchip Technol- necessary hardware and software is included to
ogys MPLAB Integrated Development Environment run the basic demonstration programs. The user
(IDE) software. Specifically, SIMICE provides hardware can program the sample microcontrollers provided
simulation for Microchips PIC12C5XX, PIC12CE5XX, with the PICDEM-2 board, on a PRO MATE II pro-
and PIC16C5X families of PICmicro 8-bit microcontrol- grammer or PICSTART-Plus, and easily test firmware.
lers. SIMICE works in conjunction with MPLAB-SIM to The MPLAB-ICE emulator may also be used with the
provide non-real-time I/O port emulation. SIMICE PICDEM-2 board to test firmware. Additional prototype
enables a developer to run simulator code for driving area has been provided to the user for adding addi-
the target system. In addition, the target system can tional hardware and connecting it to the microcontroller
provide input to the simulator code. This capability socket(s). Some of the features include a RS-232 inter-
allows for simple and interactive debugging without face, push-button switches, a potentiometer for simu-
having to manually generate MPLAB-SIM stimulus lated analog input, a Serial EEPROM to demonstrate
files. SIMICE is a valuable debugging tool for entry- usage of the I2C bus and separate headers for connec-
level system development. tion to an LCD module and a keypad.
PIC16C77X
14.10 MPLAB Integrated Development 14.12 Software Simulator (MPLAB-SIM)
Environment Software
The MPLAB-SIM Software Simulator allows code
The MPLAB IDE Software brings an ease of software development in a PC host environment. It allows the
development previously unseen in the 8-bit microcon- user to simulate the PICmicro series microcontrollers
troller market. MPLAB is a windows based application on an instruction level. On any given instruction, the
which contains: user may examine or modify any of the data areas or
provide external stimulus to any of the pins. The input/
A full featured editor
output radix can be set by the user and the execution
Three operating modes
can be performed in; single step, execute until break, or
- editor
in a trace mode.
- emulator
- simulator MPLAB-SIM fully supports symbolic debugging using
A project manager MPLAB-C17 and MPASM. The Software Simulator
Customizable tool bar and key mapping offers the low cost flexibility to develop and debug code
A status bar with project information outside of the laboratory environment making it an
Extensive on-line help excellent multi-project software development tool.
MPLAB allows you to: 14.13 MPLAB-C17 Compiler
Edit your source files (either assembly or C)
One touch assemble (or compile) and download The MPLAB-C17 Code Development System is a
to PICmicro tools (automatically updates all complete ANSI C compiler and integrated develop-
project information) ment environment for Microchips PIC17CXXX family of
Debug using: microcontrollers. The compiler provides powerful inte-
- source files gration capabilities and ease of use not found with
- absolute listing file other compilers.
The ability to use MPLAB with Microchips simulator For easier source level debugging, the compiler pro-
allows a consistent platform and the ability to easily vides symbol information that is compatible with the
switch from the low cost simulator to the full featured MPLAB IDE memory display.
emulator with minimal retraining due to development
14.14 Fuzzy Logic Development System
tools.
(fuzzyTECH-MP)
14.11 Assembler (MPASM)
fuzzyTECH-MP fuzzy logic development tool is avail-
The MPASM Universal Macro Assembler is a PC- able in two versions - a low cost introductory version,
hosted symbolic assembler. It supports all microcon- MP Explorer, for designers to gain a comprehensive
troller series including the PIC12C5XX, PIC14000, working knowledge of fuzzy logic system design; and a
PIC16C5X, PIC16CXXX, and PIC17CXX families. full-featured version, fuzzyTECH-MP, Edition for imple-
menting more complex systems.
MPASM offers full featured Macro capabilities, condi-
tional assembly, and several source and listing formats. Both versions include Microchips fuzzyLAB demon-
It generates various object code formats to support stration board for hands-on experience with fuzzy logic
Microchip's development tools as well as third party systems implementation.
programmers.
14.15 SEEVAL Evaluation and
MPASM allows full symbolic debugging from MPLAB- Programming System
ICE, Microchips Universal Emulator System.
MPASM has the following features to assist in develop- The SEEVAL SEEPROM Designers Kit supports all
ing software for specific use applications. Microchip 2-wire and 3-wire Serial EEPROMs. The kit
includes everything necessary to read, write, erase or
Provides translation of Assembler source code to program special features of any Microchip SEEPROM
object code for all Microchip microcontrollers. product including Smart Serials and secure serials.
Macro assembly capability. The Total Endurance Disk is included to aid in trade-
Produces all the files (Object, Listing, Symbol, and off analysis and reliability calculations. The total kit can
special) required for symbolic debug with significantly reduce time-to-market and result in an
Microchips emulator systems. optimized system.
Supports Hex (default), Decimal and Octal source
and listing formats.
MPASM provides a rich directive language to support
programming of the PICmicro. Directives are helpful in
making the development of your assemble source code
shorter and more maintainable.
PIC16C77X
14.16 KEELOQ Evaluation and
Programming Tools
KEELOQ evaluation and programming tools support
Microchips HCS Secure Data Products. The HCS eval-
uation kit includes an LCD display to show changing
codes, a decoder to decode transmissions, and a pro-
gramming interface to program test transmitters.
MPLAB-ICE
ICEPIC Low-Cost
774.book Page 149 Tuesday, January 29, 2013 12:02 PM
In-Circuit Emulator
Emulator Products
MPLAB
Integrated
Software Tools
Fuzzy Logic
Dev. Tool
Total Endurance
Software Model
PICSTARTPlus
Low-Cost
Universal Dev. Kit
DEVELOPMENT TOOLS FROM MICROCHIP
PRO MATE II
Advance Information
Universal
Programmer
Programmers
KEELOQ
Programmer
SEEVAL
Designers Kit
SIMICE
PICDEM-14A
PICDEM-1
PICDEM-2
PICDEM-3
Demo Boards
KEELOQ
Evaluation Kit
KEELOQ
Transponder Kit
PIC16C77X
DS30275B-page 149
774.book Page 150 Tuesday, January 29, 2013 12:02 PM
PIC16C77X
NOTES:
PIC16C77X
15.0 ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings
Ambient temperature under bias................................................................................................................ .-55 to +125C
Storage temperature .............................................................................................................................. -65C to +150C
Voltage on any pin with respect to VSS (except VDD, MCLR. and RA4).......................................... -0.3V to (VDD + 0.3V)
Voltage on VDD with respect to VSS ............................................................................................................ -0.3 to +7.5V
Voltage on MCLR with respect to VSS (Note 2).................................................................................................0 to +8.5V
Voltage on RA4 with respect to Vss ..................................................................................................................0 to +8.5V
Total power dissipation (Note 1)................................................................................................................................1.0W
Maximum current out of VSS pin ...........................................................................................................................300 mA
Maximum current into VDD pin ..............................................................................................................................250 mA
Input clamp current, IIK (VI < 0 or VI > VDD) 20 mA
Output clamp current, IOK (VO < 0 or VO > VDD) 20 mA
Maximum output current sunk by any I/O pin..........................................................................................................25 mA
Maximum output current sourced by any I/O pin ....................................................................................................25 mA
Maximum current sunk byPORTA, PORTB, and PORTE (combined) (Note 3)....................................................200 mA
Maximum current sourced by PORTA, PORTB, and PORTE (combined) (Note 3) ..............................................200 mA
Maximum current sunk by PORTC and PORTD (combined) (Note 3) ..................................................................200 mA
Maximum current sourced by PORTC and PORTD (combined) (Note 3) .............................................................200 mA
Note 1: Power dissipation is calculated as follows: Pdis = VDD x {IDD - IOH} + {(VDD - VOH) x IOH} + (VOl x IOL)
Note 2: Voltage spikes below VSS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up. Thus,
a series resistor of 50-100 should be used when applying a low level to the MCLR pin rather than pulling
this pin directly to VSS.
Note 3: PORTD and PORTE are not implemented on the PIC16C773.
NOTICE: Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above those
indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
TABLE 15-1 CROSS REFERENCE OF DEVICE SPECS FOR OSCILLATOR CONFIGURATIONS
AND FREQUENCIES OF OPERATION (COMMERCIAL DEVICES)
PIC16C773-04 PIC16C773-20 PIC16LC773-04
OSC JW Devices
PIC16C774-04 PIC16C774-20 PIC16LC774-04
VDD: 4.0V to 5.5V VDD: 4.5V to 5.5V VDD: 2.5V to 5.5V VDD: 4.0V to 5.5V
IDD: 5 mA max. at 5.5V IDD: 2.7 mA typ. at 5.5V IDD: 3.8 mA max. at 3.0V IDD: 5 mA max. at 5.5V
RC
IPD: 16 A max. at 4V IPD: 1.5 A typ. at 4V IPD: 5 A max. at 3V IPD: 16 A max. at 4V
Freq: 4 MHz max. Freq: 4 MHz max. Freq: 4 MHz max. Freq: 4 MHz max.
VDD: 4.0V to 5.5V VDD: 4.5V to 5.5V VDD: 2.5V to 5.5V VDD: 4.0V to 5.5V
IDD: 5 mA max. at 5.5V IDD: 2.7 mA typ. at 5.5V IDD: 3.8 mA max. at 3.0V IDD: 5 mA max. at 5.5V
XT
IPD: 16 A max. at 4V IPD: 1.5 A typ. at 4V IPD: 5 A max. at 3V IPD: 16 A max. at 4V
Freq: 4 MHz max. Freq: 4 MHz max. Freq: 4 MHz max. Freq: 4 MHz max.
VDD: 4.5V to 5.5V VDD: 4.5V to 5.5V VDD: 4.5V to 5.5V
IDD: 13.5 mA typ. at 5.5V IDD: 20 mA max. at 5.5V IDD: 20 mA max. at 5.5V
HS Not tested for functionality
IPD: 1.5 A typ. at 4.5V IPD: 1.5 A typ. at 4.5V IPD: 1.5 A typ. at 4.5V
Freq: 4 MHz max. Freq: 20 MHz max. Freq: 20 MHz max.
VDD: 4.0V to 5.5V VDD: 2.5V to 5.5V VDD: 2.5V to 5.5V
IDD: 52.5 A typ. at 32 IDD: 48 A max. at 32 kHz, IDD: 48 A max. at 32 kHz,
Not tested for functionality
LP kHz, 4.0V 3.0V 3.0V
IPD: 0.9 A typ. at 4.0V IPD: 5.0 A max. at 3.0V IPD: 5.0 A max. at 3.0V
Freq: 200 kHz max. Freq: 200 kHz max. Freq: 200 kHz max.
The shaded sections indicate oscillator selections which are tested for functionality, but not for MIN/MAX specifications.
It is recommended that the user select the device type that ensures the specifications required.
PIC16C77X
15.1 DC Characteristics: PIC16C77X (Commercial, Industrial)
D026* A/D Converter IAD 300 A VDD = 5.5V, A/D on, not converting
* These parameters are characterized but not tested.
Data in "Typ" column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only
and are not tested.
Note 1: This is the limit to which VDD can be lowered without losing RAM data.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors such as I/O pin
loading and switching rate, oscillator type, internal code execution pattern, and temperature also have an
impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail to rail; all I/O pins tristated, pulled to VDD
MCLR = VDD; WDT enabled/disabled as specified.
3: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is mea-
sured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD or VSS.
4: For RC osc configuration, current through Rext is not included. The current through the resistor can be esti-
mated by the formula Ir = VDD/2Rext (mA) with Rext in kOhm.
5: The current is the additional current consumed when the peripheral is enabled. This current should be
added to the base (IPD or IDD) current.
6: The bandgap voltate reference provides 1.22V to the VRL, VRH, LVD and BOR circuits. When calculating cur-
rent consumption use the following formula: IVRL + IVRH + ILVD + IBOR + IBG. Any of the IVRL, IVRH,
ILVD or IBOR can be 0.
PIC16C77X
15.2 DC Characteristics:PIC16LC77X-04 (Commercial, Industrial)
PIC16C77X
15.3 DC Characteristics: PIC16C77X (Commercial, Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40C TA +85C for industrial and
DC CHARACTERISTICS 0C TA +70C for commercial
Operating voltage VDD range as described in DC spec Section 15.1 and
Section 15.2.
Param Characteristic Sym Min Typ Max Units Conditions
No.
Input Low Voltage
I/O ports VIL
D030 with TTL buffer VSS 0.15VDD V For entire VDD range
D030A VSS 0.8V V 4.5V VDD 5.5V
D031 with Schmitt Trigger buffer
RC3 and RC4 VSS 0.3VDD V I2C compliant
All others VSS 0.2VDD For entire VDD range
D032 MCLR, OSC1 (in RC mode) VSS 0.2VDD V
D033 OSC1 (in XT, HS and LP) VSS 0.3VDD V Note1
Input High Voltage
I/O ports VIH
with TTL buffer
D040 2.0 VDD V 4.5V VDD 5.5V
D040A 0.25VDD VDD V For entire VDD range
+ 0.8V
with Schmitt Trigger buffer
D041 RC3 and RC4 0.7VDD VDD V I2C compliant
All others 0.8VDD VDD V For entire VDD range
D042 MCLR 0.8VDD VDD V
D042A OSC1 (XT, HS and LP) 0.7VDD VDD V Note1
D043 OSC1 (in RC mode) 0.9VDD VDD V
D070 PORTB weak pull-up current IPURB 50 250 400 A VDD = 5V, VPIN = VSS
Input Leakage Current
(Notes 2, 3)
D060 I/O ports (digital) IIL 1 A Vss VPIN VDD, Pin at hi-
impedance
D060A I/O ports (RA0-RA3, RA5, RB2, IIL 100 nA Vss VPIN VDD, Pin at hi-
RB3 analog) impedance
D061 MCLR, RA4/T0CKI 5 A Vss VPIN VDD
D063 OSC1 5 A Vss VPIN VDD, XT, HS and LP
osc configuration
Output Low Voltage
D080 I/O ports VOL 0.6 V IOL = 8.5 mA, VDD = 4.5V,
-40C to +85C
D083 OSC2/CLKOUT (RC osc config) 0.6 V IOL = 1.6 mA, VDD = 4.5V,
-40C to +85C
*These parameters are characterized but not tested.
Data in Typ column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only
and are not tested.
Note 1: In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended that the
PIC16C77X be driven with external clock in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels
represent normal operating conditions. Higher leakage current may be measured at different input voltages.
3: Negative current is defined as current sourced by the pin.
PIC16C77X
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40C TA +85C for industrial and
DC CHARACTERISTICS 0C TA +70C for commercial
Operating voltage VDD range as described in DC spec Section 15.1 and
Section 15.2.
Param Characteristic Sym Min Typ Max Units Conditions
No.
Output High Voltage
D090 I/O ports (Note 3) VOH VDD - 0.7 V IOH = -3.0 mA, VDD = 4.5V,
-40C to +85C
D092 OSC2/CLKOUT (RC osc config) VDD - 0.7 V IOH = -1.3 mA, VDD = 4.5V,
-40C to +85C
D150* Open-Drain High Voltage VOD 8.5 V RA4 pin
Capacitive Loading Specs on
Output Pins
D100 OSC2 pin COSC2 15 pF In XT, HS and LP modes when
external clock is used to drive
OSC1.
D101 All I/O pins and OSC2 (in RC CIO 50 pF
D102 CB 400 pF
mode) SCL, SDA in I2C mode
* These parameters are characterized but not tested.
Data in Typ column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only
and are not tested.
Note 1: In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended that the
PIC16C77X be driven with external clock in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels
represent normal operating conditions. Higher leakage current may be measured at different input voltages.
3: Negative current is defined as current sourced by the pin.
PIC16C77X
15.4 DC Characteristics: VREF
TABLE 15-2 ELECTRICAL CHARACTERISTICS: VREF
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40C TA +85C for industrial and
DC CHARACTERISTICS
0C TA +70C for commercial
Operating voltage VDD range as described in DC spec Section 15.1 and Section 15.2.
Param
Characteristic Symbol Min Typ Max Units Conditions
No.
D400 Output Voltage VRL 2.0 2.048 2.1 V VDD 2.5V
VRH 4.0 4.096 4.2 V VDD 4.5V
D401A VRL Quiescent Supply Current IVRL 70 TBD A No load on VRL.
D401B VRH Quiescent Supply Current IVRH 70 TBD A No load on VRH.
D402 Ouput Voltage Drift TCVOUT 15* 50* ppm/C Note 1
D404 External Load Source IVREFSO 5* mA
D405 External Load Sink IVREFSI -5* mA
D406 Load Regulation 1 TBD* Isource = 0 mA to
VOUT/ 5 mA
mV/mA
IOUT 1 TBD* Isink = 0 mA to
5 mA
D407 Line Regulation VOUT/
50* V/V
VDD
*These parameters are characterized but not tested.
Data in Typ column is at 5V, 25C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Production tested at TAMB = 25C. Specifications over temp limits guaranteed by characterization.
PIC16C77X
FIGURE 15-1: LOW-VOLTAGE DETECT CHARACTERISTICS
VDD
VLHYS
VLVD
(LVDIF set by hardware)
LVDIF
PIC16C77X
FIGURE 15-2: BROWN-OUT RESET CHARACTERISTICS
VDD
PIC16C77X
15.5 AC Characteristics: PIC16C77X (Commercial, Industrial)
15.5.1 TIMING PARAMETER SYMBOLOGY
The timing parameter symbols have been created following one of the following formats:
1. TppS2ppS 3. TCC:ST (I2C specifications only)
2. TppS 4. Ts (I2C specifications only)
T
F Frequency T Time
Lowercase letters (pp) and their meanings:
pp
cc CCP1 osc OSC1
ck CLKOUT rd RD
cs CS rw RD or WR
di SDI sc SCK
do SDO ss SS
dt Data in t0 T0CKI
io I/O port t1 T1CKI
mc MCLR wr WR
Uppercase letters and their meanings:
S
F Fall P Period
H High R Rise
I Invalid (Hi-impedance) V Valid
L Low Z Hi-impedance
I2C only
AA output access High High
BUF Bus free Low Low
TCC:ST (I2C specifications only)
CC
HD Hold SU Setup
ST
DAT DATA input hold STO STOP condition
STA START condition
PIC16C77X
FIGURE 15-3: LOAD CONDITIONS
Load condition 1 Load condition 2
VDD/2
RL
CL CL
Pin Pin
VSS VSS
RL = 464
CL = 50 pF for all pins except OSC2, but including PORTD and PORTE outputs as
ports
15 pF for OSC2 output
Note: PORTD and PORTE are not implemented on the PIC16C773.
PIC16C77X
15.5.2 TIMING DIAGRAMS AND SPECIFICATIONS
OSC1
1 3 3 4 4
2
CLKOUT
PIC16C77X
FIGURE 15-5: CLKOUT AND I/O TIMING
Q4 Q1 Q2 Q3
OSC1
10 11
CLKOUT
13 12
19 18
14 16
I/O Pin
(input)
17 15
20, 21
PIC16C77X
FIGURE 15-6: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
VDD
MCLR
30
Internal
POR
33
PWRT
Time-out
32
OSC
Time-out
Internal
RESET
Watchdog
Timer
RESET
31
34
34
I/O Pins
VDD BVDD
35
PIC16C77X
FIGURE 15-8: BANDGAP START-UP TIME
Enable Bandgap
TBGAP
Bandgap stable
PIC16C77X
TABLE 15-9 A/D CONVERTER CHARACTERISTICS:
Param Sym Characteristic Min Typ Max Units Conditions
No.
A01 NR Resolution 12 bits bit Min. resolution for A/D is 1 mV,
VREF+ = AVDD = 4.096V,
VREF- = AVSS = 0V,
VREF- VAIN VREF+
A03 EIL Integral error +/-2 LSb VREF+ = AVDD = 4.096V,
VREF- = AVSS = 0V,
VREF- VAIN VREF+
A04 EDL Differential error +2 LSb No missing codes to 12-bits
-1 LSb VREF+ = AVDD = 4.096V,
VREF- = AVSS = 0V,
VREF- VAIN VREF+
A06 EOFF Offset error less than VREF+ = AVDD = 4.096V,
2 LSb VREF- = AVSS = 0V,
VREF- VAIN VREF+
A07 EGN Gain Error +/- 2LSb LSb VREF+ = AVDD = 4.096V,
VREF- = AVSS = 0V,
VREF- VAIN VREF+
A10 Monotonicity guaranteed(3) AVSS VAIN VREF+
A20 VREF Reference voltage 4.096 VDD +0.3V V Absolute minimum electrical spec to
(VREF+ VREF-) ensure 12-bit accuracy.
A21 VREF+ Reference V High VREF- AVDD V Min. resolution for A/D is 1 mV
(AVDD or VREF+)
A22 VREF- Reference V Low AVSS VREF+ V Min. resolution for A/D is 1 mV
(AVSS or VREF-)
A25 VAIN Analog input voltage VREFL VREFH V
A30 ZAIN Recommended 2.5 k
impedance of analog
voltage source
A50 IREF VREF input current 10 A During VAIN acquisition.
(Note 2) Based on differential of VHOLD to VAIN.
To charge CHOLD see Section 11.0.
During A/D conversion cycle.
* These parameters are characterized but not tested.
Data in Typ column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: When A/D is off, it will not consume any current other than minor leakage current. The power down current spec includes any
such leakage from the A/D module.
2: VREF current is from External VREF+, OR VREF-, or AVSS, or AVDD pin, whichever is selected as reference input.
3: The A/D conversion result never decreases with an increase in the input voltage and has no missing codes.
PIC16C77X
FIGURE 15-9: A/D CONVERSION TIMING (NORMAL MODE)
BSF ADCON0, GO
1/2 Tcy
134
131
Q4
130
A/D CLK
A/D DATA 9 8 7 6 3 2 1 0
ADIF
GO DONE
SAMPLING STOPPED
SAMPLE 132
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the
SLEEP instruction to be executed.
PIC16C77X
FIGURE 15-10: A/D CONVERSION TIMING (SLEEP MODE)
BSF ADCON0, GO
134
131
Q4
130
A/D CLK
A/D DATA 9 8 7 6 3 2 1 0
ADIF
GO DONE
SAMPLING STOPPED
SAMPLE 132
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the
SLEEP instruction to be executed.
PIC16C77X
FIGURE 15-11: TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
RA4/T0CKI
40 41
42
RC0/T1OSO/T1CKI
45 46
47 48
TMR0 or
TMR1
PIC16C77X
FIGURE 15-12: CAPTURE/COMPARE/PWM TIMINGS (CCP1 AND CCP2)
RC1/T1OSI/CCP2
and RC2/CCP1
(Capture Mode)
50 51
52
RC1/T1OSI/CCP2
and RC2/CCP1
(Compare or PWM Mode)
53 54
PIC16C77X
FIGURE 15-13: PARALLEL SLAVE PORT TIMING (PIC16C774)
RE2/CS
RE0/RD
RE1/WR
65
RD7:RD0
62
64
63
Note: Refer to Figure 15-3 for load conditions.
PIC16C77X
FIGURE 15-14: USART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
RC6/TX/CK
pin 121
121
RC7/RX/DT
pin
120
122
Note: Refer to Figure 15-3 for load conditions.
RC6/TX/CK
pin 125
RC7/RX/DT
pin
126
PIC16C77X
NOTES:
PIC16C77X
16.0 DC AND AC CHARACTERISTICS GRAPHS AND TABLES
The graphs and tables provided in this section are for design guidance and are not tested.
In some graphs or tables, the data presented are outside specified operating range (i.e., outside specified VDD
range). This is for information only and devices are guaranteed to operate properly only within the specified range.
The data presented in this section is a statistical summary of data collected on units from different lots over a period
of time and matrix samples. 'Typical' represents the mean of the distribution at 25C. 'Max' or 'min' represents
(mean + 3) or (mean - 3) respectively, where is standard deviation, over the whole temperature range.
PIC16C77X
NOTES:
PIC16C77X
17.0 PACKAGING INFORMATION
17.1 Package Marking Information
XXXXXXXXXXX PIC16C774/JW
XXXXXXXXXXX
XXXXXXXXXXX
AABBCDE 1305HAT
XXXXXXXXXXXXXXXXXXXXXXXX PIC16C773-20/SO
XXXXXXXXXXXXXXXXXXXXXXXX
AABBCDE 1310SAA
XXXXXXXXXXXX PIC16C773
XXXXXXXXXXXX 20I/SS
AABBCAE 9817SBP
* Standard OTP marking consists of Microchip part number, year code, week code, facility code, mask
rev#, and assembly code. For OTP marking beyond this, certain price adders apply. Please check with
your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP price.
PIC16C77X
Package Marking Information (Contd)
XXXXXXXXXXXXX PIC16C774/JW
XXXXXXXXXXXXX
XXXXXXXXXXXXX
AABBCDE 1305HAT
XXXXXXXXXXXX PIC16C774
XXXXXXXXXXXX -04/PT
XXXXXXXXXXXX
AABBCDE 1311HAT
XXXXXXXXXXXX PIC16C774
XXXXXXXXXXXX -20/PQ
XXXXXXXXXXXX
AABBCDE 1304SAT
XXXXXXXXXXXX PIC16C774
XXXXXXXXXXXX -04/L
XXXXXXXXXXXX
AABBCDE 1303SAT
PIC16C77X
17.2 K04-070 28-Lead Skinny Plastic Dual In-line (SP) 300 mil
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
2
n 1
E1 A1
R L
c
A2 B1
eB B p
PIC16C77X
17.3 K04-080 28-Lead Ceramic Dual In-line with Window (JW) 300 mil
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
W2 D
2
n 1
W1
E1
A
A1
R L
c
B1
eB A2
B p
Units INCHES* MILLIMETERS
Dimension Limits MIN NOM MAX MIN NOM MAX
PCB Row Spacing 0.300 7.62
Number of Pins n 28 28
Pitch p 0.098 0.100 0.102 2.49 2.54 2.59
Lower Lead Width B 0.016 0.019 0.021 0.41 0.47 0.53
Upper Lead Width B1 0.050 0.058 0.065 1.27 1.46 1.65
Shoulder Radius R 0.010 0.013 0.015 0.25 0.32 0.38
Lead Thickness c 0.008 0.010 0.012 0.20 0.25 0.30
Top to Seating Plane A 0.170 0.183 0.195 4.32 4.64 4.95
Top of Lead to Seating Plane A1 0.107 0.125 0.143 2.72 3.18 3.63
Base to Seating Plane A2 0.015 0.023 0.030 0.00 0.57 0.76
Tip to Seating Plane L 0.135 0.140 0.145 3.43 3.56 3.68
Package Length D 1.430 1.458 1.485 36.32 37.02 37.72
Package Width E 0.285 0.290 0.295 7.24 7.37 7.49
Radius to Radius Width E1 0.255 0.270 0.285 6.48 6.86 7.24
Overall Row Spacing eB 0.345 0.385 0.425 8.76 9.78 10.80
Window Width W1 0.130 0.140 0.150 0.13 0.14 0.15
Window Length W2 0.290 0.300 0.310 0.29 0.3 0.31
* Controlling Parameter.
PIC16C77X
17.4 K04-052 28-Lead Plastic Small Outline (SO) Wide, 300 mil
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
E1
E
p
B
2
n 1
X
45 L
R2
c
A
A1
R1
L1 A2
PIC16C77X
17.5 K04-073 28-Lead Plastic Shrink Small Outline (SS) 5.30 mm
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
E1
E
p
B
2
n 1
L
A
R2
c
A1
R1
A2
L1
PIC16C77X
17.6 K04-016 40-Lead Plastic Dual In-line (P) 600 mil
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
2
n 1
E1 A1
A
R L
c
B1
A2
eB B p
PIC16C77X
17.7 K04-014 40-Lead Ceramic Dual In-line with Window (JW) 600 mil
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
2
n 1
E1 A1
A
R c L
eB B1
A2 B p
PIC16C77X
17.8 K04-076 44-Lead Plastic Thin Quad Flatpack (PT) 10x10x1 mm Body, 1.0/0.1 mm Lead Form
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
E1
E
# leads = n1
D D1
2
1
B
n
X x 45
L A
R2
c
R1 A1
L1 A2
PIC16C77X
17.9 K04-071 44-Lead Plastic Quad Flatpack (PQ) 10x10x2 mm Body, 1.6/0.15 mm Lead Form
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
E1
E
# leads = n1
D D1
2
1
B
n
X x 45
L
R2
c A
R1
A1
L1 A2
PIC16C77X
17.10 K04-048 44-Lead Plastic Leaded Chip Carrier (L) Square
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
E1
E
# leads = n1
D D1
n 12
CH2 x 45 CH1 x 45 A3
R1 L
A
A1 35
B1
c R2
B
A2
p
E2 D2
Units INCHES* MILLIMETERS
Dimension Limits MIN NOM MAX MIN NOM MAX
Number of Pins n 44 44
Pitch p 0.050 1.27
Overall Pack. Height A 0.165 0.173 0.180 4.19 4.38 4.57
Shoulder Height A1 0.095 0.103 0.110 2.41 2.60 2.79
Standoff A2 0.015 0.023 0.030 0.38 0.57 0.76
Side 1 Chamfer Dim. A3 0.024 0.029 0.034 0.61 0.74 0.86
Corner Chamfer (1) CH1 0.040 0.045 0.050 1.02 1.14 1.27
Corner Chamfer (other) CH2 0.000 0.005 0.010 0.00 0.13 0.25
Overall Pack. Width E1 0.685 0.690 0.695 17.40 17.53 17.65
Overall Pack. Length D1 0.685 0.690 0.695 17.40 17.53 17.65
Molded Pack. Width E 0.650 0.653 0.656 16.51 16.59 16.66
Molded Pack. Length D 0.650 0.653 0.656 16.51 16.59 16.66
Footprint Width E2 0.610 0.620 0.630 15.49 15.75 16.00
Footprint Length D2 0.610 0.620 0.630 15.49 15.75 16.00
Pins along Width n1 11 11
Lead Thickness c 0.008 0.010 0.012 0.20 0.25 0.30
Upper Lead Width B1 0.026 0.029 0.032 0.66 0.74 0.81
Lower Lead Width B 0.015 0.018 0.021 0.38 0.46 0.53
Upper Lead Length L 0.050 0.058 0.065 1.27 1.46 1.65
Shoulder Inside Radius R1 0.003 0.005 0.010 0.08 0.13 0.25
J-Bend Inside Radius R2 0.015 0.025 0.035 0.38 0.64 0.89
Mold Draft Angle Top 0 5 10 0 5 10
Mold Draft Angle Bottom 0 5 10 0 5 10
*
Controlling Parameter.
Dimension B1 does not include dam-bar protrusions. Dam-bar protrusions shall not exceed 0.003
(0.076 mm) per side or 0.006 (0.152 mm) more than dimension B1.
Dimensions D and E do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed 0.010" (0.254 mm) per side or 0.020" (0.508 mm) more than dimensions D or E.
JEDEC equivalent:MO-047 AC
PIC16C77X
NOTES:
PIC16C77X
APPENDIX A: REVISION HISTORY
Version Date Revision Description
A 1999 This is a new data sheet. However, the devices described in this data sheet are
the upgrades to the devices found in the PIC16C7X Data Sheet, DS30390E.
B 2013 Added a note to each package drawing.
Packages 28-pin PDIP, 28-pin windowed CERDIP, 40-pin PDIP, 40-pin windowed CERDIP,
28-pin SOIC, 28-pin SSOP 44-pin TQFP, 44-pin MQFP,
44-pin PLCC
PIC16C77X
NOTES:
PIC16C77X
INDEX C
Capture (CCP Module) ...................................................... 48
A
Block Diagram ........................................................... 48
A/D ................................................................................... 117 CCP Pin Configuration .............................................. 48
A/D Converter Enable (ADIE Bit) ............................... 19 CCPR1H:CCPR1L Registers .................................... 48
A/D Converter Flag (ADIF Bit) ................................... 20 Changing Between Capture Prescalers .................... 48
ADCON0 Register .................................................... 117 Software Interrupt ...................................................... 48
ADCON1 Register ............................................ 117, 118 Timer1 Mode Selection .............................................. 48
ADRES Register ...................................................... 117 Capture/Compare/PWM (CCP) ......................................... 47
Analog Port Pins ...................................... 7, 8, 9, 36, 37 CCP1 ......................................................................... 47
Block Diagram .......................................................... 120 CCP1CON Register ........................................... 47
Configuring Analog Port ........................................... 119 CCPR1H Register ............................................. 47
Conversion time ....................................................... 125 CCPR1L Register .............................................. 47
Conversions ............................................................. 121 Enable (CCP1IE Bit) .......................................... 19
converter characteristics .................. 156, 157, 158, 165 Flag (CCP1IF Bit) .............................................. 20
Faster Conversion - Lower Resolution Tradeoff ...... 125 RC2/CCP1 Pin ................................................. 7, 9
Internal Sampling Switch (Rss) Impedence ............. 123 CCP2 ......................................................................... 47
Operation During Sleep ........................................... 126 CCP2CON Register ........................................... 47
Sampling Requirements ........................................... 123 CCPR2H Register ............................................. 47
Sampling Time ......................................................... 123 CCPR2L Register .............................................. 47
Source Impedance ................................................... 123 Enable (CCP2IE Bit) .......................................... 21
Special Event Trigger (CCP) ...................................... 49 Flag (CCP2IF Bit) .............................................. 22
A/D Conversion Clock ...................................................... 121 RC1/T1OSI/CCP2 Pin ..................................... 7, 9
ACK .................................................................................... 64 Interaction of Two CCP Modules ............................... 47
Acknowledge Data bit, AKD ............................................... 56 Timer Resources ....................................................... 47
Acknowledge Pulse ............................................................ 64 CCP1CON ......................................................................... 15
Acknowledge Sequence Enable bit, AKE .......................... 56 CCP1CON Register ........................................................... 47
Acknowledge Status bit, AKS ............................................ 56 CCP1M3:CCP1M0 Bits ............................................. 47
ADCON0 Register ............................................................ 117 CCP1X:CCP1Y Bits ................................................... 47
ADCON1 Register .................................................... 117, 118 CCP2CON ......................................................................... 15
ADRES ............................................................................. 117 CCP2CON Register ........................................................... 47
ADRES Register .......................................... 13, 14, 117, 126 CCP2M3:CCP2M0 Bits ............................................. 47
AKD .................................................................................... 56 CCP2X:CCP2Y Bits ................................................... 47
AKE .................................................................................... 56 CCPR1H Register ........................................................ 13, 15
AKS .............................................................................. 56, 79 CCPR1L Register .............................................................. 15
Application Note AN578, "Use of the SSP CCPR2H Register ........................................................ 13, 15
Module in the I2C Multi-Master Environment." ................... 63 CCPR2L Register ........................................................ 13, 15
Architecture CKE ................................................................................... 54
PIC16C63A/PIC16C73B Block Diagram ...................... 5 CKP ................................................................................... 55
PIC16C65B/PIC16C74B Block Diagram ...................... 6 Clock Polarity Select bit, CKP ............................................ 55
Assembler Code Examples
MPASM Assembler .................................................. 147 Loading the SSPBUF register ................................... 58
B Code Protection ....................................................... 127, 141
Compare (CCP Module) .................................................... 49
Banking, Data Memory ................................................ 11, 16
Block Diagram ........................................................... 49
Baud Rate Generator ......................................................... 73
CCP Pin Configuration .............................................. 49
BF .................................................................... 54, 64, 79, 82
CCPR1H:CCPR1L Registers .................................... 49
Block Diagrams
Software Interrupt ...................................................... 49
Baud Rate Generator ................................................. 73
Special Event Trigger .......................................... 43, 49
I2C Master Mode ........................................................ 71
Timer1 Mode Selection .............................................. 49
I2C Module ................................................................. 63
Configuration Bits ............................................................ 127
SSP (I2C Mode) ......................................................... 63
Conversion Considerations .............................................. 187
SSP (SPI Mode) ......................................................... 57
BOR. See Brown-out Reset D
BRG ................................................................................... 73 D/A ..................................................................................... 54
Brown-out Reset (BOR) ................... 127, 131, 132, 133, 134 Data Memory ..................................................................... 11
BOR Status (BOR Bit) ................................................ 23 Bank Select (RP1:RP0 Bits) ................................ 11, 16
Buffer Full bit, BF ............................................................... 64 General Purpose Registers ....................................... 11
Buffer Full Status bit, BF .................................................... 54 Register File Map ...................................................... 12
Bus Arbitration ................................................................... 90 Special Function Registers ........................................ 13
Bus Collision Data/Address bit, D/A ........................................................ 54
Section ....................................................................... 90 DC Characteristics
Bus Collision During a RESTART Condition ...................... 93 PIC16C73 ................................................................ 152
Bus Collision During a Start Condition ............................... 91 PIC16C74 ................................................................ 152
Bus Collision During a Stop Condition ............................... 94 Development Support ...................................................... 145
Development Tools .......................................................... 145
Device Differences ........................................................... 187
Direct Addressing .............................................................. 25
PIC16C77X
E Restart Condition Flowchart ...................................... 77
Errata ................................................................................... 4 Slave Mode ................................................................ 64
Slave Reception ........................................................ 65
External Power-on Reset Circuit ...................................... 132
Slave Transmission ................................................... 65
F SSPBUF .................................................................... 64
Firmware Instructions ....................................................... 143 Start Condition Flowchart .......................................... 75
Flowcharts Stop Condition Flowchart ........................................... 88
Acknowledge .............................................................. 86 Stop Condition Receive or Transmit timing ............... 87
Master Receiver ......................................................... 83 Stop Condition timing ................................................. 87
Master Transmit ......................................................... 80 Waveforms for 7-bit Reception .................................. 65
Restart Condition ....................................................... 77 Waveforms for 7-bit Transmission ............................. 66
2
Start Condition ........................................................... 75 I C Module Address Register, SSPADD ........................... 64
2
Stop Condition ........................................................... 88 I C Slave Mode .................................................................. 64
FSR Register .......................................................... 13, 14, 15 ICEPIC Low-Cost PIC16CXXX In-Circuit Emulator ......... 145
Fuzzy Logic Dev. System (fuzzyTECH-MP) .................. 147 ID Locations ............................................................. 127, 141
In-Circuit Serial Programming (ICSP) ...................... 127, 141
G INDF .................................................................................. 15
GCE ................................................................................... 56 INDF Register .............................................................. 13, 14
General Call Address Sequence ........................................ 69 Indirect Addressing ............................................................ 25
General Call Address Support ........................................... 69 FSR Register ............................................................. 11
General Call Enable bit, GCE ............................................ 56 Instruction Format ............................................................ 143
Instruction Set .................................................................. 143
I Summary Table ....................................................... 144
I/O Ports ............................................................................. 27 INTCON ............................................................................. 15
I2C ...................................................................................... 63 INTCON Register ............................................................... 18
I2C Master Mode Receiver Flowchart ................................ 83 GIE Bit ....................................................................... 18
I2C Master Mode Reception ............................................... 82 INTE Bit ..................................................................... 18
I2C Master Mode Restart Condition ................................... 76 INTF Bit ..................................................................... 18
I2C Mode Selection ............................................................ 63 PEIE Bit ..................................................................... 18
I2C Module RBIE Bit ..................................................................... 18
Acknowledge Flowchart ............................................. 86 RBIF Bit ............................................................... 18, 30
Acknowledge Sequence timing .................................. 85 T0IE Bit ...................................................................... 18
Addressing ................................................................. 64 T0IF Bit ...................................................................... 18
Baud Rate Generator ................................................. 73 Inter-Integrated Circuit (I2C) .............................................. 53
Block Diagram ............................................................ 71 internal sampling switch (Rss) impedence ...................... 123
BRG Block Diagram ................................................... 73 Interrupt Sources ..................................................... 127, 137
BRG Reset due to SDA Collision ............................... 92 Block Diagram ......................................................... 137
BRG Timing ............................................................... 73 Capture Complete (CCP) ........................................... 48
Bus Arbitration ........................................................... 90 Compare Complete (CCP) ......................................... 49
Bus Collision .............................................................. 90 Interrupt on Change (RB7:RB4 ) ............................... 30
Acknowledge ...................................................... 90 RB0/INT Pin, External ...................................... 7, 8, 138
Restart Condition ............................................... 93 TMR0 Overflow .................................................. 40, 138
Restart Condition Timing (Case1) ...................... 93 TMR1 Overflow .................................................... 41, 43
Restart Condition Timing (Case2) ...................... 93 TMR2 to PR2 Match .................................................. 46
Start Condition ................................................... 91 TMR2 to PR2 Match (PWM) ................................ 45, 50
Start Condition Timing ................................. 91, 92 USART Receive/Transmit Complete ......................... 97
Stop Condition ................................................... 94 Interrupts, Context Saving During .................................... 138
Stop Condition Timing (Case1) .......................... 94 Interrupts, Enable Bits
Stop Condition Timing (Case2) .......................... 94 A/D Converter Enable (ADIE Bit) ............................... 19
Transmit Timing ................................................. 90 CCP1 Enable (CCP1IE Bit) ................................. 19, 48
Bus Collision timing .................................................... 90 CCP2 Enable (CCP2IE Bit) ....................................... 21
Clock Arbitration ......................................................... 89 Global Interrupt Enable (GIE Bit) ....................... 18, 137
Clock Arbitration Timing (Master Transmit) ................ 89 Interrupt on Change (RB7:RB4) Enable
Conditions to not give ACK Pulse .............................. 64 (RBIE Bit) ........................................................... 18, 138
General Call Address Support ................................... 69 Peripheral Interrupt Enable (PEIE Bit) ....................... 18
Master Mode .............................................................. 71 PSP Read/Write Enable (PSPIE Bit) ......................... 19
Master Mode 7-bit Reception timing .......................... 84 RB0/INT Enable (INTE Bit) ........................................ 18
Master Mode Operation ............................................. 72 SSP Enable (SSPIE Bit) ............................................ 19
Master Mode Start Condition ..................................... 74 TMR0 Overflow Enable (T0IE Bit) ............................. 18
Master Mode Transmission ........................................ 79 TMR1 Overflow Enable (TMR1IE Bit) ........................ 19
Master Mode Transmit Sequence .............................. 72 TMR2 to PR2 Match Enable (TMR2IE Bit) ................ 19
Master Transmit Flowchart ........................................ 80 USART Receive Enable (RCIE Bit) ........................... 19
Multi-Master Communication ..................................... 90 USART Transmit Enable (TXIE Bit) ........................... 19
Multi-master Mode ..................................................... 72
Operation ................................................................... 63
Repeat Start Condition timing .................................... 76
PIC16C77X
Interrupts, Flag Bits PCON Register .......................................................... 23, 133
A/D Converter Flag (ADIF Bit) ................................... 20 BOR Bit ...................................................................... 23
CCP1 Flag (CCP1IF Bit) ................................ 20, 48, 49 POR Bit ...................................................................... 23
CCP2 Flag (CCP2IF Bit) ............................................ 22 PICDEM-1 Low-Cost PICmicro Demo Board .................. 146
Interrupt on Change (RB7:RB4) Flag PICDEM-2 Low-Cost PIC16CXX Demo Board ................ 146
(RBIF Bit) ..................................................... 18, 30, 138 PICDEM-3 Low-Cost PIC16CXXX Demo Board ............. 146
PSP Read/Write Flag (PSPIF Bit) .............................. 20 PICSTART Plus Entry Level Development System ...... 145
RB0/INT Flag (INTF Bit) ............................................. 18 PIE1 Register .................................................................... 19
SSP Flag (SSPIF Bit) ................................................. 20 ADIE Bit ..................................................................... 19
TMR0 Overflow Flag (T0IF Bit) .......................... 18, 138 CCP1IE Bit ................................................................ 19
TMR1 Overflow Flag (TMR1IF Bit) ............................ 20 PSPIE Bit ................................................................... 19
TMR2 to PR2 Match Flag (TMR2IF Bit) ..................... 20 RCIE Bit ..................................................................... 19
USART Receive Flag (RCIF Bit) ................................ 20 SSPIE Bit ................................................................... 19
USART Transmit Flag (TXIE Bit) ............................... 20 TMR1IE Bit ................................................................ 19
TMR2IE Bit ................................................................ 19
K TXIE Bit ..................................................................... 19
KeeLoq Evaluation and Programming Tools ................. 148 PIE2 Register .................................................................... 21
CCP2IE Bit ................................................................ 21
M Pinout Descriptions
Master Clear (MCLR) ....................................................... 7, 8 PIC16C63A/PIC16C73B .............................................. 7
MCLR Reset, Normal Operation .............. 131, 133, 134 PIC16C65B/PIC16C74B .............................................. 8
MCLR Reset, SLEEP ............................... 131, 133, 134 PIR1 Register .................................................................... 20
Memory Organization ADIF Bit ..................................................................... 20
Data Memory ............................................................. 11 CCP1IF Bit ................................................................. 20
Program Memory ....................................................... 11 PSPIF Bit ................................................................... 20
MPLAB Integrated Development Environment Software . 147 RCIF Bit ..................................................................... 20
Multi-Master Communication ............................................. 90 SSPIF Bit ................................................................... 20
Multi-Master Mode ............................................................. 72 TMR1IF Bit ................................................................ 20
TMR2IF Bit ................................................................ 20
O
TXIF Bit ...................................................................... 20
OPCODE Field Descriptions ............................................ 143 PIR2 Register .................................................................... 22
OPTION_REG Register ..................................................... 17 CCP2IF Bit ................................................................. 22
INTEDG Bit ................................................................ 17 Pointer, FSR ...................................................................... 25
PS2:PS0 Bits ....................................................... 17, 39 POR. See Power-on Reset
PSA Bit ................................................................. 17, 39 PORTA ...................................................................... 7, 8, 15
RBPU Bit .................................................................... 17 Analog Port Pins ...................................................... 7, 8
T0CS Bit ............................................................... 17, 39 Initialization ................................................................ 27
T0SE Bit ............................................................... 17, 39 PORTA Register ........................................................ 27
OSC1/CLKIN Pin ............................................................. 7, 8 RA3:RA0 and RA5 Port Pins ..................................... 28
OSC2/CLKOUT Pin ......................................................... 7, 8 RA4/T0CKI Pin .................................................. 7, 8, 28
Oscillator Configuration .................................................... 128 RA5/SS/AN4 Pin .......................................................... 8
HS .................................................................... 128, 133 TRISA Register .......................................................... 27
LP ..................................................................... 128, 133 PORTA Register ........................................................ 13, 126
RC ............................................................ 128, 130, 133 PORTB ...................................................................... 7, 8, 15
XT .................................................................... 128, 133 Initialization ................................................................ 29
Oscillator, Timer1 ......................................................... 41, 43 PORTB Register ........................................................ 29
Oscillator, WDT ................................................................ 139 Pull-up Enable (RBPU Bit) ......................................... 17
P RB0/INT Edge Select (INTEDG Bit) .......................... 17
RB0/INT Pin, External ..................................... 7, 8, 138
P ......................................................................................... 54
RB3:RB0 Port Pins .................................................... 29
Packaging ........................................................................ 175
RB7:RB4 Interrupt on Change ................................. 138
Paging, Program Memory ............................................ 11, 24
RB7:RB4 Interrupt on Change Enable (RBIE Bit) .... 18,
Parallel Slave Port (PSP) ......................................... 9, 34, 37
138
Block Diagram ............................................................ 37
RB7:RB4 Interrupt on Change Flag (RBIF Bit) ... 18, 30,
RE0/RD/AN5 Pin .............................................. 9, 36, 37
138
RE1/WR/AN6 Pin ............................................. 9, 36, 37
RB7:RB4 Port Pins .................................................... 30
RE2/CS/AN7 Pin .............................................. 9, 36, 37
TRISB Register .......................................................... 29
Read Waveforms ....................................................... 38
PORTB Register ........................................................ 13, 126
Read/Write Enable (PSPIE Bit) .................................. 19
PORTC ...................................................................... 7, 9, 15
Read/Write Flag (PSPIF Bit) ...................................... 20
Block Diagram ........................................................... 32
Select (PSPMODE Bit) .................................. 34, 35, 37
Initialization ................................................................ 32
Write Waveforms ....................................................... 37
PORTC Register ........................................................ 32
PCL Register ................................................................ 13, 14
RC0/T1OSO/T1CKI Pin ........................................... 7, 9
PCLATH Register .................................................. 13, 14, 15
RC1/T1OSI/CCP2 Pin ............................................. 7, 9
RC2/CCP1 Pin ......................................................... 7, 9
RC3/SCK/SCL Pin ................................................... 7, 9
PIC16C77X
RC4/SDI/SDA Pin .................................................... 7, 9 Programming, Device Instructions ................................... 143
RC5/SDO Pin ........................................................... 7, 9 PWM (CCP Module) .......................................................... 50
RC6/TX/CK Pin .................................................. 7, 9, 98 Block Diagram ........................................................... 50
RC7/RX/DT Pin ............................................ 7, 9, 98, 99 CCPR1H:CCPR1L Registers ..................................... 50
TRISC Register .................................................... 32, 97 Duty Cycle ................................................................. 50
PORTC Register ................................................................ 13 Example Frequencies/Resolutions ............................ 51
PORTD ..................................................................... 9, 15, 37 Output Diagram ......................................................... 50
Block Diagram ............................................................ 34 Period ........................................................................ 50
Parallel Slave Port (PSP) Function ............................ 34 Set-Up for PWM Operation ........................................ 51
PORTD Register ........................................................ 34 TMR2 to PR2 Match ............................................ 45, 50
TRISD Register .......................................................... 34 TMR2 to PR2 Match Enable (TMR2IE Bit) ................ 19
PORTD Register ................................................................ 13 TMR2 to PR2 Match Flag (TMR2IF Bit) ..................... 20
PORTE ........................................................................... 9, 15
Analog Port Pins .............................................. 9, 36, 37 Q
Block Diagram ............................................................ 35 Q-Clock .............................................................................. 50
Input Buffer Full Status (IBF Bit) ................................ 35
Input Buffer Overflow (IBOV Bit) ................................ 35
R
Output Buffer Full Status (OBF Bit) ............................ 35 R/W .................................................................................... 54
PORTE Register ........................................................ 35 R/W bit ............................................................................... 64
PSP Mode Select (PSPMODE Bit) ................ 34, 35, 37 R/W bit ............................................................................... 65
RE0/RD/AN5 Pin .............................................. 9, 36, 37 RCE,Receive Enable bit, RCE ........................................... 56
RE1/WR/AN6 Pin ............................................. 9, 36, 37 RCREG .............................................................................. 15
RE2/CS/AN7 Pin .............................................. 9, 36, 37 RCSTA Register .......................................................... 15, 98
TRISE Register .......................................................... 35 CREN Bit ................................................................... 98
PORTE Register ........................................................ 13, 126 FERR Bit .................................................................... 98
Postscaler, Timer2 OERR Bit ................................................................... 98
Select (TOUTPS3:TOUTPS0 Bits) ............................ 45 RX9 Bit ...................................................................... 98
Postscaler, WDT ................................................................ 39 RX9D Bit .................................................................... 98
Assignment (PSA Bit) .......................................... 17, 39 SPEN Bit .............................................................. 97, 98
Block Diagram ............................................................ 40 SREN Bit ................................................................... 98
Rate Select (PS2:PS0 Bits) ................................. 17, 39 Read/Write bit, R/W ........................................................... 54
Switching Between Timer0 and WDT ........................ 40 Receive Overflow Indicator bit, SSPOV ............................. 55
Power-on Reset (POR) .................... 127, 131, 132, 133, 134 Register File ....................................................................... 11
Oscillator Start-up Timer (OST) ....................... 127, 132 Register File Map ............................................................... 12
POR Status (POR Bit) ................................................ 23 Registers
Power Control (PCON) Register .............................. 133 FSR
Power-down (PD Bit) ................................................. 16 Summary ........................................................... 15
Power-on Reset Circuit, External ............................. 132 INDF
Power-up Timer (PWRT) ................................. 127, 132 Summary ........................................................... 15
Time-out (TO Bit) ....................................................... 16 INTCON
Time-out Sequence .................................................. 133 Summary ........................................................... 15
Time-out Sequence on Power-up .................... 135, 136 PCL
PR2 Register ...................................................................... 14 Summary ........................................................... 15
Prescaler, Capture ............................................................. 48 PCLATH
Prescaler, Timer0 ............................................................... 39 Summary ........................................................... 15
Assignment (PSA Bit) .......................................... 17, 39 PORTB
Block Diagram ............................................................ 40 Summary ........................................................... 15
Rate Select (PS2:PS0 Bits) ................................. 17, 39 SSPSTAT .................................................................. 54
Switching Between Timer0 and WDT ........................ 40 STATUS
Prescaler, Timer1 ............................................................... 42 Summary ........................................................... 15
Select (T1CKPS1:T1CKPS0 Bits) .............................. 41 Summary ................................................................... 13
Prescaler, Timer2 ............................................................... 50 TMR0
Select (T2CKPS1:T2CKPS0 Bits) .............................. 45 Summary ........................................................... 15
PRO MATE II Universal Programmer ............................ 145 TRISB
Product Identification System ........................................... 199 Summary ........................................................... 15
Program Counter Reset ....................................................................... 127, 131
PCL Register .............................................................. 24 Block Diagram ......................................................... 131
PCLATH Register .............................................. 24, 138 Reset Conditions for All Registers ........................... 134
Reset Conditions ...................................................... 133 Reset Conditions for PCON Register ...................... 133
Program Memory ............................................................... 11 Reset Conditions for Program Counter .................... 133
Interrupt Vector .......................................................... 11 Reset Conditions for STATUS Register ................... 133
Paging .................................................................. 11, 24 Restart Condition Enabled bit, RSE ................................... 56
Program Memory Map ............................................... 11 Revision History ............................................................... 187
Reset Vector .............................................................. 11 RSE ................................................................................... 56
Program Verification ......................................................... 141
Programming Pin (Vpp) .................................................... 7, 8
PIC16C77X
S SSP Module
SPI Master Mode ....................................................... 59
SAE .................................................................................... 56
SCK .................................................................................... 57 SPI Master./Slave Connection ................................... 58
SCL .................................................................................... 64 SPI Slave Mode ......................................................... 60
SSPCON1 Register ................................................... 63
SDA .................................................................................... 64
SDI ..................................................................................... 57 SSP Overflow Detect bit, SSPOV ...................................... 64
SDO ................................................................................... 57 SSPADD Register .............................................................. 14
SSPBUF ...................................................................... 15, 64
SEEVAL Evaluation and Programming System ............ 147
Serial Clock, SCK .............................................................. 57 SSPBUF Register .............................................................. 13
Serial Clock, SCL ............................................................... 64 SSPCON Register ............................................................. 13
SSPCON1 ................................................................... 55, 63
Serial Data Address, SDA .................................................. 64
Serial Data In, SDI ............................................................. 57 SSPCON2 ......................................................................... 56
Serial Data Out, SDO ......................................................... 57 SSPEN .............................................................................. 55
SSPIF ................................................................................ 65
Slave Select Synchronization ............................................ 60
Slave Select, SS ................................................................ 57 SSPM3:SSPM0 ................................................................. 55
SLEEP ............................................................. 127, 131, 140 SSPOV .................................................................. 55, 64, 82
SSPSTAT .................................................................... 54, 64
SMP ................................................................................... 54
Software Simulator (MPLAB-SIM) ................................... 147 SSPSTAT Register ............................................................ 14
SPBRG Register ................................................................ 14 Stack .................................................................................. 24
Start bit (S) ........................................................................ 54
SPE .................................................................................... 56
Special Features of the CPU ........................................... 127 Start Condition Enabled bit, SAE ....................................... 56
Special Function Registers ................................................ 13 STATUS Register ...................................................... 16, 138
C Bit ........................................................................... 16
PIC16C73 .................................................................. 13
PIC16C73A ................................................................ 13 DC Bit ........................................................................ 16
PIC16C74 .................................................................. 13 IRP Bit ....................................................................... 16
PD Bit ........................................................................ 16
PIC16C74A ................................................................ 13
RP1:RP0 Bits ............................................................. 16
PIC16C76 .................................................................. 13
TO Bit ........................................................................ 16
PIC16C77 .................................................................. 13
Z Bit ........................................................................... 16
Speed, Operating ................................................................. 1
Stop bit (P) ......................................................................... 54
SPI
Stop Condition Enable bit .................................................. 56
Master Mode .............................................................. 59
Synchronous Serial Port .................................................... 53
Serial Clock ................................................................ 57
Synchronous Serial Port Enable bit, SSPEN ..................... 55
Serial Data In ............................................................. 57
Synchronous Serial Port Mode Select bits,
Serial Data Out .......................................................... 57
SSPM3:SSPM0 ................................................................. 55
Serial Peripheral Interface (SPI) ................................ 53
Slave Select ............................................................... 57 T
SPI clock .................................................................... 59
T1CON .............................................................................. 15
SPI Mode ................................................................... 57
T1CON Register .......................................................... 15, 41
SPI Clock Edge Select, CKE ............................................. 54
T1CKPS1:T1CKPS0 Bits ........................................... 41
SPI Data Input Sample Phase Select, SMP ...................... 54
T1OSCEN Bit ............................................................ 41
SPI Master/Slave Connection ............................................ 58
T1SYNC Bit ............................................................... 41
SPI Module
TMR1CS Bit ............................................................... 41
Master/Slave Connection ........................................... 58
TMR1ON Bit .............................................................. 41
Slave Mode ................................................................ 60
T2CON Register .......................................................... 15, 45
Slave Select Synchronization .................................... 60
T2CKPS1:T2CKPS0 Bits ........................................... 45
Slave Synch Timnig ................................................... 60
TMR2ON Bit .............................................................. 45
SS ...................................................................................... 57
TOUTPS3:TOUTPS0 Bits ......................................... 45
SSP .................................................................................... 53
Timer0 ............................................................................... 39
Block Diagram (SPI Mode) ........................................ 57
Block Diagram ........................................................... 39
Enable (SSPIE Bit) ..................................................... 19
Clock Source Edge Select (T0SE Bit) ................. 17, 39
Flag (SSPIF Bit) ......................................................... 20
Clock Source Select (T0CS Bit) .......................... 17, 39
RA5/SS/AN4 Pin .......................................................... 8
Overflow Enable (T0IE Bit) ........................................ 18
RC3/SCK/SCL Pin ................................................... 7, 9
Overflow Flag (T0IF Bit) .................................... 18, 138
RC4/SDI/SDA Pin .................................................... 7, 9
Overflow Interrupt .............................................. 40, 138
RC5/SDO Pin ........................................................... 7, 9
RA4/T0CKI Pin, External Clock ............................... 7, 8
SPI Mode ................................................................... 57
Timer1 ............................................................................... 41
SSPADD .................................................................... 64
Block Diagram ........................................................... 42
SSPBUF ............................................................... 59, 64
Capacitor Selection ................................................... 43
SSPCON1 .................................................................. 55
Clock Source Select (TMR1CS Bit) ........................... 41
SSPCON2 .................................................................. 56
External Clock Input Sync (T1SYNC Bit) ................... 41
SSPSR ................................................................. 59, 64
Module On/Off (TMR1ON Bit) ................................... 41
SSPSTAT ............................................................. 54, 64
Oscillator .............................................................. 41, 43
TMR2 Output for Clock Shift ................................ 45, 46
Oscillator Enable (T1OSCEN Bit) .............................. 41
SSP I2C
Overflow Enable (TMR1IE Bit) .................................. 19
SSP I2C Operation ..................................................... 63
Overflow Flag (TMR1IF Bit) ....................................... 20
PIC16C77X
Overflow Interrupt ................................................ 41, 43 PSPMODE Bit ................................................ 34, 35, 37
RC0/T1OSO/T1CKI Pin ........................................... 7, 9 TXREG .............................................................................. 15
RC1/T1OSI/CCP2 Pin .............................................. 7, 9 TXSTA Register ................................................................. 97
Special Event Trigger (CCP) ................................ 43, 49 BRGH Bit ............................................................. 97, 99
T1CON Register ........................................................ 41 CSRC Bit ................................................................... 97
TMR1H Register ........................................................ 41 SYNC Bit ................................................................... 97
TMR1L Register ......................................................... 41 TRMT Bit .................................................................... 97
Timer2 TX9 Bit ....................................................................... 97
Block Diagram ............................................................ 46 TX9D Bit .................................................................... 97
PR2 Register ........................................................ 45, 50 TXEN Bit .................................................................... 97
SSP Clock Shift .................................................... 45, 46
T2CON Register ........................................................ 45 U
TMR2 Register ........................................................... 45 UA ...................................................................................... 54
TMR2 to PR2 Match Enable (TMR2IE Bit) ................ 19 Universal Synchronous Asynchronous Receiver Transmitter
TMR2 to PR2 Match Flag (TMR2IF Bit) ..................... 20 (USART)
TMR2 to PR2 Match Interrupt ........................ 45, 46, 50 Asynchronous Receiver
Timing Diagrams Setting Up Reception ....................................... 104
Acknowledge Sequence Timing ................................. 85 Timing Diagram ............................................... 105
Baud Rate Generator with Clock Arbitration .............. 73 Update Address, UA .......................................................... 54
BRG Reset Due to SDA Collision .............................. 92 USART ............................................................................... 97
Brown-out Reset ...................................................... 163 Asynchronous Mode ................................................ 102
Bus Collision Master Transmission ....................................... 103
Start Condition Timing ....................................... 91 Receive Block Diagram ................................... 105
Bus Collision During a Restart Condition (Case 1) .... 93 Transmit Block Diagram .................................. 102
Bus Collision During a Restart Condition (Case2) ..... 93 Baud Rate Generator (BRG) ..................................... 99
Bus Collision During a Start Condition (SCL = 0) ...... 92 Baud Rate Error, Calculating ............................. 99
Bus Collision During a Stop Condition ....................... 94 Baud Rate Formula ........................................... 99
Bus Collision for Transmit and Acknowledge ............. 90 Baud Rates, Asynchronous Mode (BRGH=0) . 100
Capture/Compare/PWM ........................................... 169 Baud Rates, Asynchronous Mode (BRGH=1) . 101
CLKOUT and I/O ...................................................... 162 Baud Rates, Synchronous Mode ..................... 100
External Clock Timing .............................................. 161 High Baud Rate Select (BRGH Bit) ............. 97, 99
I2C Master Mode First Start bit timing ........................ 74 Sampling ............................................................ 99
I2C Master Mode Reception timing ............................ 84 Clock Source Select (CSRC Bit) ................................ 97
I2C Master Mode Transmission timing ....................... 81 Continuous Receive Enable (CREN Bit) .................... 98
Master Mode Transmit Clock Arbitration .................... 89 Framing Error (FERR Bit) .......................................... 98
Power-up Timer ....................................................... 163 Mode Select (SYNC Bit) ............................................ 97
Repeat Start Condition ............................................... 76 Overrun Error (OERR Bit) .......................................... 98
Reset ........................................................................ 163 RC6/TX/CK Pin ........................................................ 7, 9
Slave Synchronization ............................................... 60 RC7/RX/DT Pin ........................................................ 7, 9
Start-up Timer .......................................................... 163 RCSTA Register ........................................................ 98
Stop Condition Receive or Transmit .......................... 87 Receive Data, 9th bit (RX9D Bit) ............................... 98
Time-out Sequence on Power-up .................... 135, 136 Receive Enable (RCIE Bit) ........................................ 19
Timer0 ...................................................................... 168 Receive Enable, 9-bit (RX9 Bit) ................................. 98
Timer1 ...................................................................... 168 Receive Flag (RCIF Bit) ............................................. 20
USART Asynchronous Master Transmission ........... 103 Serial Port Enable (SPEN Bit) ............................. 97, 98
USART Synchronous Receive ................................. 171 Single Receive Enable (SREN Bit) ............................ 98
USART Synchronous Reception .............................. 109 Synchronous Master Mode ...................................... 107
USART Synchronous Transmission ................ 108, 171 Reception ........................................................ 109
USART, Asynchronous Reception ........................... 105 Transmission ................................................... 108
Wake-up from SLEEP via Interrupt .......................... 141 Synchronous Slave Mode ........................................ 110
Watchdog Timer ....................................................... 163 Transmit Data, 9th Bit (TX9D) ................................... 97
TMR0 ................................................................................. 15 Transmit Enable (TXEN Bit) ...................................... 97
TMR0 Register ................................................................... 13 Transmit Enable (TXIE Bit) ........................................ 19
TMR1H ............................................................................... 15 Transmit Enable, Nine-bit (TX9 Bit) ........................... 97
TMR1H Register ................................................................ 13 Transmit Flag (TXIE Bit) ............................................ 20
TMR1L ............................................................................... 15 Transmit Shift Register Status (TRMT Bit) ................ 97
TMR1L Register ................................................................. 13 TXSTA Register ......................................................... 97
TMR2 ................................................................................. 15
TMR2 Register ................................................................... 13
TRISA Register .......................................................... 14, 126
TRISB Register .......................................................... 14, 126
TRISC Register .................................................................. 14
TRISD Register .................................................................. 14
TRISE Register .................................................... 14, 35, 126
IBF Bit ........................................................................ 35
IBOV Bit ..................................................................... 35
OBF Bit ...................................................................... 35
PIC16C77X
W
W Register ....................................................................... 138
Wake-up from SLEEP .............................................. 127, 140
Interrupts .......................................................... 133, 134
MCLR Reset ............................................................ 134
Timing Diagram ........................................................ 141
WDT Reset .............................................................. 134
Watchdog Timer (WDT) ........................................... 127, 139
Block Diagram .......................................................... 139
Enable (WDTE Bit) ................................................... 139
Programming Considerations .................................. 139
RC Oscillator ............................................................ 139
Time-out Period ....................................................... 139
WDT Reset, Normal Operation ................ 131, 133, 134
WDT Reset, SLEEP ......................................... 133, 134
Waveform for General Call Address Sequence ................. 69
WCOL .................................................. 55, 74, 79, 82, 85, 87
WCOL Status Flag ............................................................. 74
Write Collision Detect bit, WCOL ....................................... 55
WWW, On-Line Support ...................................................... 4
PIC16C77X
BIT/REGISTER CROSS-REFERENCE T0CS .................................................. OPTION_REG<5>
T0IE ................................................... INTCON<5>
LIST T0IF ................................................... INTCON<2>
T0SE .................................................. OPTION_REG<4>
ADCS1:ADCS0 ..................................ADCON0<7:6>
T1CKPS1:T1CKPS0 .......................... T1CON<5:4>
ADIE ...................................................PIE1<6>
T1OSCEN .......................................... T1CON<3>
ADIF ...................................................PIR1<6>
T1SYNC ............................................. T1CON<2>
ADON .................................................ADCON0<0>
T2CKPS1:T2CKPS0 .......................... T2CON<1:0>
BF .......................................................SSPSTAT<0>
TMR1CS ............................................ T1CON<1>
BOR ...................................................PCON<0>
TMR1IE .............................................. PIE1<0>
BRGH .................................................TXSTA<2>
TMR1IF .............................................. PIR1<0>
C .........................................................STATUS<0>
TMR1ON ............................................ T1CON<0>
CCP1IE ..............................................PIE1<2>
TMR2IE .............................................. PIE1<1>
CCP1IF ..............................................PIR1<2>
TMR2IF .............................................. PIR1<1>
CCP1M3:CCP1M0 .............................CCP1CON<3:0>
TMR2ON ............................................ T2CON<2>
CCP1X:CCP1Y ..................................CCP1CON<5:4>
TO ...................................................... STATUS<4>
CCP2IE ..............................................PIE2<0>
TOUTPS3:TOUTPS0 ......................... T2CON<6:3>
CCP2IF ..............................................PIR2<0>
TRMT ................................................. TXSTA<1>
CCP2M3:CCP2M0 .............................CCP2CON<3:0>
TX9 .................................................... TXSTA<6>
CCP2X:CCP2Y ..................................CCP2CON<5:4>
TX9D .................................................. TXSTA<0>
CHS2:CHS0 .......................................ADCON0<5:3>
TXEN ................................................. TXSTA<5>
CKE ....................................................SSPSTAT<6>
TXIE ................................................... PIE1<4>
CKP ....................................................SSPCON<4>
TXIF ................................................... PIR1<4>
CREN .................................................RCSTA<4>
UA ...................................................... SSPSTAT<1>
CSRC .................................................TXSTA<7>
WCOL ................................................ SSPCON<7>
D/A .....................................................SSPSTAT<5>
Z ......................................................... STATUS<2>
DC ......................................................STATUS<1>
FERR .................................................RCSTA<2>
GIE .....................................................INTCON<7>
GO/DONE ..........................................ADCON0<2>
IBF ......................................................TRISE<7>
IBOV ...................................................TRISE<5>
INTE ...................................................INTCON<4>
INTEDG ..............................................OPTION_REG<6>
INTF ...................................................INTCON<1>
IRP .....................................................STATUS<7>
OBF ....................................................TRISE<6>
OERR .................................................RCSTA<1>
P .........................................................SSPSTAT<4>
PCFG2:PCFG0 ..................................ADCON1<2:0>
PD ......................................................STATUS<3>
PEIE ...................................................INTCON<6>
POR ...................................................PCON<1>
PS2:PS0 .............................................OPTION_REG<2:0>
PSA ....................................................OPTION_REG<3>
PSPIE .................................................PIE1<7>
PSPIF .................................................PIR1<7>
PSPMODE .........................................TRISE<4>
R/W ....................................................SSPSTAT<2>
RBIE ...................................................INTCON<3>
RBIF ...................................................INTCON<0>
RBPU .................................................OPTION_REG<7>
RCIE ...................................................PIE1<5>
RCIF ...................................................PIR1<5>
RP1:RP0 ............................................STATUS<6:5>
RX9 ....................................................RCSTA<6>
RX9D ..................................................RCSTA<0>
S .........................................................SSPSTAT<3>
SMP ...................................................SSPSTAT<7>
SPEN .................................................RCSTA<7>
SREN .................................................RCSTA<5>
SSPEN ...............................................SSPCON<5>
SSPIE .................................................PIE1<3>
SSPIF .................................................PIR1<3>
SSPM3:SSPM0 ..................................SSPCON<3:0>
SSPOV ...............................................SSPCON<6>
SYNC .................................................TXSTA<4>
PIC16C77X
ON-LINE SUPPORT
Microchip provides on-line support on the Microchip
World Wide Web (WWW) site.
The web site is used by Microchip as a means to make
files and information easily available to customers. To
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The web site and file transfer site provide a variety of
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available for consideration is:
Latest Microchip Press Releases
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Questions
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Conferences for products, Development Sys-
tems, technical information and more
Listing of seminars and events
PIC16C77X
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip prod-
uct. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation
can better serve you, please FAX your comments to the Technical Publications Manager at (602) 786-7578.
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5. What deletions from the data sheet could be made without affecting the overall usefulness?
8. How would you improve our software, systems, and silicon products?
PIC16C77X
PIC16C77X PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO. -XX X /XX XXX
Examples:
Device Frequency Temperature Package Pattern g) PIC16C774 -04/P 301 = Commercial temp.,
Range Range PDIP package, 4 MHz, normal VDD limits, QTP
pattern #301.
h) PIC16LC773 - 04I/SO = Industrial temp., SOIC
package, 200 kHz, Extended VDD limits.
Device PIC16C77X(1), PIC16C77XT(2);VDD range 4.0V to 5.5V
PIC16LC77X(1), PIC16LC77XT(2);VDD range 2.5V to 5.5V i) PIC16C774 - 20I/P = Industrial temp., PDIP
package, 20MHz, normal VDD limits.
* JW Devices are UV erasable and can be programmed to any device configuration. JW Devices meet the electrical requirement of
each oscillator type (including LC devices).
Sales and Support
Data Sheets
Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recom-
mended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:
1. Your local Microchip sales office
2. The Microchip Worldwide Site (www.microchip.com)
Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using.
PIC16C77X
Note the following details of the code protection feature on Microchip devices:
Microchip products meet the specification contained in their particular Microchip Data Sheet.
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchips Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
Microchip is willing to work with the customer who is concerned about the integrity of their code.
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as unbreakable.
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchips code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
QUALITY MANAGEMENT SYSTEM Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
CERTIFIED BY DNV Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Companys quality system processes and procedures
== ISO/TS 16949 ==
are for its PIC MCUs and dsPIC DSCs, KEELOQ code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchips quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.