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    AT89S52 Microcontroller

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    mahamd saied

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd

    AT89S52 Microcontroller

    Uploaded by

    mahamd saied
    16 views10 pages

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    AT89S52 Microcontroller.docx

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    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    16 views10 pages

    AT89S52 Microcontroller

    Uploaded by

    mahamd saied

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    of 10

    AT89S52 Microcontroller

    Features:
    -

    Compatible with MCS-51 Products


    8K Bytes of flash memory
    Endurance: 10,000 Write/Erase Cycles
    4.0V to 5.5V Operating Range
    256 x 8-bit Internal RAM
    Watchdog Timer
    Three 16-bit Timer/Counters
    32 Programmable I/O Lines
    Three 16-bit Timer/Counters

    RST Pin:
    -

    Reset input. A high on this pin for two machine cycles while the oscillator is
    running resets the device.
    This pin drives high for 98 oscillator periods after the Watchdog times out.
    The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this
    feature.

    LCD Interfacing with 8051 Microcontroller

    Category

    Pin NO.

    Power Pins

    Contrast Pin

    Pin Name Function


    Ground Pin, connected to

    VSS Ground
    2

    VDD or VCC

    Voltage Pin +5V

    Vo or VEE

    Contrast Setting, connected


    to VCC thorough a variable
    resistor

    Control Pins

    RS

    Register Select Pin:


    RS=0 Command mode,
    RS=1 Data mode
    5

    RW

    :Read/ Write pin


    ,RW=0 Write mode
    RW=1 Read mode
    6

    7-14

    D0-D7

    Enable, a high to low pulse


    need to enable the LCD

    Data Pins

    Data Pins, Stores the Data


    to be displayed on LCD or
    the command instructions

    Backlight Pins

    15
    16

    LED+ or A To power the Backlight +5V


    LED- or K

    Backlight Ground

    GSM Interfacing With AT89S52


    RXD&TXD:
    RXD: is the first pin in port 3(P3.0),Its used in serial
    communications(as serial input port).
    TX of GSM to RXD (PIN 10) of 8051
    TXD: is the second pin in port 3(P3.1),Its used in serial
    communications(as serial output port).
    RX of GSM to TX (PIN 11) of 8051
    -

    Interrupts:
    Port 3(P3.2 & P3.3)
    The interrupts refer to a notification, communicated to the
    controller, by a hardware device or software.
    on receipt of which controller momentarily stops and responds to
    the interrupt.
    Whenever an interrupt occurs the controller completes the
    execution of the current instruction and starts the execution of
    Interrupt Service Routine (ISR) or Interrupt Handler .
    Each of these interrupt sources can be individually enabled or
    disabled by setting or clearing a bit in Special Function Register IE. IE
    also contains a global disable bit, EA, which disables all
    interrup111111ts at once.
    -

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