JPH07122796B2 - Processor - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a processor, and more particularly to a structural architecture of musical sound synthesis in the processor.

BACKGROUND OF THE INVENTION In recent years, electronic musical instruments have been computerized. But,
The part related to the generation of musical sounds that requires a large amount of high-speed data calculation is performed by hardware with a dedicated structure called a tone generator circuit, and the microcomputer is a control input to the musical instrument (input from the keyboard or console panel, MIDI etc. External control input, input from an internal or external performance memory, etc.) and transfer commands suitable for the tone generator circuit to the tone generator circuit.

There are some problems in the system architecture of an electronic musical instrument in which tone generation processing is performed by sound source circuit hardware, and control input processing of a musical instrument is performed by a microcomputer. First, since the tone generator circuit hardware is composed of a storage device for temporarily holding data at various stages of processing various tone parameters and an arithmetic circuit for performing arithmetic operations, the circuit scale is inevitably large. Typically, it is about twice as large as a microcomputer. Secondly, there is a limit in variably controlling the method of synthesizing the musical tone performed by the tone generator circuit hardware by the microcomputer. For example, the polyphonic number (polyphonic number) is fixed in hardware and cannot be changed by a command from the microcomputer. Further, since the sampling frequency of the musical sound is fixed by the hardware of the tone generator circuit, it cannot be changed by a command from the microcomputer. Such control limits become a barrier when designing new sound source circuit hardware. That is, a large-scale circuit change is often unavoidable, which requires a great deal of development time and labor. Furthermore, the communication protocol or interface (transfer method, command set, etc.) between the microcomputer and the tone generator circuit hardware must be reexamined and redeveloped for each tone generator circuit hardware.

For the above reasons, the applicant of the present application has continued research on the system architecture of a new electronic musical instrument that can generate musical tones only by program control of a microcomputer without using sound source circuit hardware, and finally realizes it. saw.

In order to realize a new system architecture of electronic musical instruments, one of the problems to be solved is the sampling frequency of the musical sound There has been a problem of how to effectively maintain the interval at which a computer generates a digital tone signal. Further, there has been desired a mechanism capable of easily setting an optimum musical tone sampling frequency in accordance with various uses of electronic musical instruments, for example, a method of synthesizing musical tones, a degree of complexity of the processing, a polyphonic number and the like.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to allow a microcomputer to generate a musical tone by program control without the need for sound source circuit hardware as in the conventional art, and to solve the problem caused by program control. In particular, it solves the problem of establishing a musical sound sampling period during operation, and changes various specifications and designs related to the functions of electronic musical instruments.
It is an object of the present invention to provide a processing device that realizes a function of selecting an optimum musical tone sampling period that can immediately cope with a change in the number of polyphonics, a change in a musical tone synthesis method, a change in musical instrument control processing, and the like.

According to the present invention, in order to achieve the above object, a program storage means for storing a program for processing an input for controlling a musical instrument and a program for generating a musical tone, and this program. An address control circuit means for controlling the address of the storage means, a data storage means for storing data necessary for generating a musical tone, an arithmetic circuit means, and each instruction of the program of the program storage means to decode the respective means of the respective means. An operation control circuit means for controlling an operation, and a microcomputer having timer interrupt control circuit means for generating an interrupt signal at a sampling period of a musical sound, and the interrupt from the timer interrupt control circuit means. A program for generating the musical sound in response to a signal. A musical tone is generated by executing the program in the microcomputer, and the sampling period of the musical tone, which is an interval at which the interrupt signal is generated, is variably programmable in the timer interrupt control circuit means. A processing device is provided.

That is, according to the present invention, the timer interrupt control circuit means interrupts the work performed by the microcomputer by an interrupt signal and executes a program for generating a musical tone, so that a musical tone sample is generated at each musical tone sampling cycle. This problem is effectively solved in the program control method. That is, the process of generating a musical tone is prioritized over other processes, and is executed each time an interrupt signal is generated from the timer interrupt control circuit means. Since the timer interrupt control circuit means is basically composed of a timer (counter), the interval of generation of the interrupt signal is very stable. Further, since a musical tone sample is generated each time an interrupt signal is generated, the interrupt signal generation interval is nothing but the musical tone sampling period. Further, according to the invention, the timer interrupt control circuit means is programmable. Therefore, the interrupt signal can be generated from the timer interrupt control circuit means at an optimum interval in accordance with the polyphonic number, the method of synthesizing the musical sound, and the like. For example, it is assumed that the timer interrupt control circuit means is composed of a presettable down counter. The microcomputer presets data representing the sampling period in this counter at an appropriate time (for example, at the time of initial setting processing at power-on). The counter decrements the count value for each clock (a signal from a master clock source such as a crystal oscillator). When the count value reaches zero, an interrupt signal is generated from the counter and requests the microcomputer to interrupt. Further, this interrupt signal resets the preset data (held) to the counter. As described above, the timer interrupt control circuit means interrupts at the sampling cycle desired by the microcomputer, and the microcomputer executes the tone generation processing each time.

The tone generation processing (interrupt processing) must be completed before the next interrupt signal is output from the timer interrupt control circuit means. If this cannot be done, the sampling cycle of the musical sound cannot be maintained. The time required for the tone generation processing depends on the content thereof, for example, the number of polyphonics, the method of synthesizing the tone, and the degree of complexity of processing. In other words, it depends on the execution time of the tone generation processing program. For example, if the other conditions are the same and the polyphonic number is halved, the execution time of the tone generation processing program is halved. In this case, there is no problem even if the sampling rate of the musical sound is increased. Rather, considering the conversion of the digital / analog converter, it is better to increase the sampling speed. On the other hand, depending on the application, there are cases where high-quality and spectrum-rich musical tones are required. In this case, the polyphonic number is sacrificed, but it is necessary to synthesize one sound by complicated processing to provide a musical sound that meets the required conditions. Even in such a case, a musical tone sampling cycle suitable for it can be considered. The present invention makes it possible to generate musical tones in a musical tone sampling cycle that meets each of the above-described various specification conditions.

In one configuration example, the microcomputer is realized by an integrated circuit chip, and the means is added on the chip,
A digital-analog (D / A) converter that converts the generated digital musical tone signal to an analog signal and a port that receives an input that controls the musical instrument are also mounted. Therefore, sound source circuit hardware is not required, and the overall circuit scale can be greatly reduced. In the conventional case, since the circuit scale of the sound source circuit LSI chip is large, there is a limit to the yield in the chip manufacturing (the yield is almost inversely proportional to the chip area). Therefore, the present invention can significantly reduce the manufacturing cost of the device.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of the electronic musical instrument according to this embodiment. The entire apparatus is controlled by the microcomputer 1. In particular, according to the present invention, the microcomputer 1 performs not only the control input process of the musical instrument but also the process of generating a musical sound.
It does not require any tone generator circuit hardware for tone generation. Switch section 4 consisting of keyboard 2 and function keys 3
Is a control input source of the musical instrument, and the information input from the switch unit 4 is processed by the microcomputer 1. The analog-converted tone signal generated by the microcomputer 1 is filtered by the low-pass filter 5, and the amplifier 6
Is amplified and is emitted through the speaker 7. The power supply circuit 8 supplies necessary power to the microcomputer 1, the low pass filter, and the amplifier 6.

The internal structure of the microcomputer 1 is shown in a block diagram in FIG. The illustrated elements are mounted on a single chip. The actually manufactured one has a chip size of 5 × 5 mm, the number of simultaneous polyphonic sounds of 8 tones, and the musical tone synthesis method is PCM (waveform reading method). However, the present invention uses other polyphonic numbers and other musical tone synthesis methods. Can also be applied to.

The control ROM 31 stores a program for processing various control inputs of the musical instrument and a program for generating musical tones.
The program word (command) of the designated address is sequentially output from the M address control unit 39 via the ROM address decoder 32. In the concrete example, the program word length is
It is 28 bits, and a part of the program word is RO as the lower part (address within page) of the address to be read next.
Although the next address method is input to the M address control unit 39, the present invention can be applied to a program counter method. RAM address control unit 33 is control ROM 31
Specifies the address of the corresponding register in the RAM 34 when the operand of the instruction from specifies a register. The RAM 34 is a register group and is used in general-purpose calculation, flag calculation, and calculation of musical tones. The adder / subtractor / logical operation unit 35 and the multiplier 36 are used when the instruction from the control ROM 32 is an operation instruction. In particular, the multiplier 36 is used for the calculation of the musical tone waveform, and as an optimization therefor, the first and second data inputs (for example, 16-bit data) are multiplied to obtain the data of the same length (16 bits) as the input. It is designed to output. The RAM 34, the adder / subtractor 35, and the multiplier 36 constitute an arithmetic circuit (AU). Pitch data, envelope data (rate, level) in ROM37 for control data and waveform
Various tone control parameters such as, and tone waveform data of PCM (pulse code modulation) are stored. The envelope data and the tone waveform data are prepared for each tone color of the tone. Operation analysis unit (operation control circuit)
38 decodes the operation code of the instruction from the control ROM 31 and sends a control signal to each part of the circuit in order to execute the instructed operation.

In order to execute the musical sound generation program of the control ROM 31 every predetermined time, this device employs a timer interrupt. That is, the interrupt control unit 40 having a timer sends a control signal (interrupt signal) to the ROM address control unit 39 at regular intervals, and by this signal,
The ROM address control unit 39 saves (holds) the address of the instruction of the main program to be executed next, and sets the start address of the interrupt processing program (subroutine) for generating a musical sound instead. As a result, the interrupt processing program is started. Since there is a return instruction at the end of the interrupt processing program, when this return instruction is decoded by the operation analysis unit 38, RO
The M address control unit 39 sets the saved address again and returns to the main program.

The interrupt controller 40 is programmable according to the present invention. That is, the microcomputer 1 can freely set the interval at which the interrupt signal is generated by the interrupt controller 40 (sound sampling period). Details will be described later.

The input port 41 and the output port 42 are used for key scanning of the keyboard 2 and the function keys 3. The musical sound generated in the interrupt processing program is converted into an analog signal by the digital / analog converter 43 and output to the outside.

FIG. 3A shows the flow of the main program of the microcomputer 1 of this embodiment. A1 is an initial process when the power is turned on, and clears the RAM (register group) 34 of the microcomputer 1 and sets initial values such as rhythm tempo. Further, in this initial processing, the musical tone sampling period data is set in the interrupt control unit 40. At A2, the microcomputer 1 outputs a signal for key scanning from the output port 42 and takes in the state of the switch section 4 from the input port 41 to store the states of the function keys and keyboard keys in the key buffer area of the RAM 34. . At A3, the function key whose state has changed is identified from the state of the function key 3 obtained at A2, and the instructed function is executed (for example, musical tone number set, envelope number set, rhythm number set, etc.). . At A4, the changed key (key depression, key release) is identified from the state of the keyboard 2 obtained at A2. Next, at A5, key assignment processing for sound generation processing A9 is performed from the processing result of A4. In A6, when the demo performance key is pressed with the function key 3, the demo performance data (sequencer data) is sequentially read from the control data / waveform ROM 37 and processed, thereby performing the key assignment processing for the sound generation processing A9. To do. At A7, when the rhythm start key is pressed, the rhythm data is sequentially read from the control data / waveform ROM 37, and the key assign process for the tone generation process A9 is performed.
In the flow round timer processing A8, in order to know the timing of an event required in the main flow, the flow round time (this is obtained by counting the number of timer interrupts executed during one round of the flow. The processing is performed based on the interrupt timer processing B3 described later.) To obtain an envelope timer (envelope calculation cycle) and a rhythm reference value. In the pronunciation processing A9, various calculations are performed to actually generate musical tones from the data set in A5, A6 and A7, and the result is RA
Set it in the sound source processing register (Fig. 6) in M34. A10
Is a preparation process for the next main flow pass, and the NEW ON state indicating the change to the key depression state obtained in this pass is set to O
N OFF or NEW OFF state that indicates a change to the key release state O
Perform processing such as changing during FF.

FIG. 3B shows the flow of the interrupt processing program for generating the musical sound. At B1, the musical tone waveform data (accumulated waveform value for 8 sounds) generated at the previous interrupt sound source processing B2 is sent to the D / A converter 43. As a result, the musical tone samples are given to the D / A converter 43 in a constant cycle. In the next sound source processing B2, musical tones of each channel are generated and accumulated. In the past, this processing was performed on the tone generator circuit hardware. Details will be described later. In the next interrupt timer processing B3, the interrupt takes every predetermined time, so that the timer register (RA
Add 1 each time you pass through (inside M34).

In this embodiment, the registers to be written by the main program in the interrupt processing program are
Since the contents are not rewritten, the register save and restore processes that are performed at the start and end of the normal interrupt process are unnecessary. That is, since the registers on the RAM 34 are independent of the registers related to the musical tone processing and the registers related to other processing, the transition from the main program to the interrupt processing can be performed without delay as much as possible.

Details of the sound source processing B2 are shown in FIG. 3C. RAM for waveform addition with C1
After clearing the area (see FIG. 6), processing C2 to C9 for eight channels is performed in order. At the end of each channel processing, the tone waveform value of the channel is added to the data in the RAM area for waveform addition.

FIG. 4 illustrates the flow of operation of the embodiment over time. A, B, C, D, E, and F are fragments of the main program (FIG. 3A), and interrupt processing (FIG. 3B) is executed at regular intervals (musical sound sampling time). The time chart shows it as shown in FIG. As shown in the figure, each time an interrupt is entered, a tone waveform signal is input to the D / A converter 43, and a corresponding analog signal is output to the outside.

FIG. 7 shows the processing of C2 to C9 in FIG. 3C in detail for one channel. Channel processing is roughly divided into envelope processing (D1 to D7) and waveform processing (D8 to D21).
Consists of.

FIG. 8 shows an envelope generated by the envelope processing. A musical tone envelope is composed of several steps (segments). 4 in the figure
Shown in segments. In the figure, Δx is the sampling period of the envelope, and Δy is the change width of the envelope value. In the channel envelope processing (D1 to D7), the envelope is calculated for each sampling time and it is checked whether the step target level has been reached. When they match, the target value is currently set in the envelope register (see FIG. 6), so that it is detected in the tone generation processing A9 of the main program, and the data (Δx, Δy) for the envelope of the next step is detected. , Target envelope value) is set in each register.

In detail, D1 increments every timer register and interrupt for comparing with the envelope calculation cycle Δx, and when D2 matches Δx, the addition / subtraction flag of the data Δy of the envelope displacement at D3 (sign bit )
To determine whether the envelope is rising or falling, and subtract or add the current envelope with D4 and D5, respectively. At D6, it is checked whether the current envelope has reached the target envelope value, and if so, the target level is set to the current envelope. As a result, the data of the next envelope step is set in the tone generation processing A9 of the main program. When the current envelope of zero is read in the pronunciation processing A9, it is processed as the end of the pronunciation.

Next, the waveform processing D8 to D21 will be described. In the waveform processing, the waveform data of two adjacent addresses is read from the waveform ROM using the integer part of the current address, and the expected waveform value for the current address indicated by (integer part + fractional part) is calculated by interpolation. ing. The reason why interpolation is necessary is that the waveform sampling period by interrupt is constant and the added value of the address (pitch data) covers a certain range for application to musical instruments. If waveform data is prepared, there is no need for interpolation, but the storage capacity will be unacceptable.) Since the deterioration and distortion of the tone color due to the interpolation are more remarkable in the high tone range, the original sound is usually reproduced at a cycle faster than the recording sampling cycle of the original sound. In this embodiment, the cycle of reproduction of the original sound (A4) is doubled (Fig. 9). Therefore, when the address addition value is 0.5, the sound of A4 can be obtained. in this case,
In A # 4, the added address value is 0.529, and when A3,
It becomes 1. These address addition values are stored as pitch data in the control data / waveform ROM 37.When the key is pressed, the pitch data corresponding to the key and the waveform start address, waveform end address, and waveform of the selected tone color are generated in the tone generation process A9. The loop address is set in the corresponding register of the RAM 34, that is, the address addition value register, the start address / current address register, the end address register, and the loop address register.

For reference, FIG. 10 shows the interpolated waveform data with respect to time. In the figure, the white circles indicate the waveform data value at the address of the waveform ROM, and the black circles indicate the interpolated values.

There are various interpolation methods, but linear interpolation is used here. The waveform generation processing D8 to D21 shown in FIG. 7 will be described in detail. First, at D8, the address addition value is added to the current address to obtain a new current address. The current address is compared with the end address in D9. If the current address> the end address, the next physical or logical address (operation) is set by D10 and D11, and if the current address <the end address, D12. The address of is calculated, and the waveform ROM is accessed by the integer part at D14 to obtain the next waveform data.
The loop address is the address next to the end address in operation. That is, in the case of FIG. 9, the illustrated waveform is repeatedly read. Therefore, when the current address = end address, the waveform data of the loop address is read as the next address (D13). The waveform ROM is accessed by the integer part of the current address by D15 and D16, and the current waveform data is read. Next, the current waveform value is subtracted from the next waveform value in D17, the difference is multiplied by the fractional part of the current address in D18, and the result is added to the current waveform value in D19 to obtain the linear interpolation value of the waveform. Ask. This linearly interpolated data is multiplied by the current envelope value to obtain the tone data value of the channel (D20), and the tone data is added to the contents of the waveform addition register to accumulate the tone data (D21).

So far, as is clear, the microcomputer 1
Each time an interrupt signal is generated from the interrupt control unit 40, the interrupt processing is performed to generate a musical sound, thereby maintaining the musical sound sampling cycle during operation. Further, according to the present invention, the generation interval of the interrupt signal generated by the interrupt control unit 40, that is, the sampling period of the musical tone can be variably programmed by the microcomputer 1. Various configurations of the programmable interrupt control unit 40 can be considered. Two examples will be described below.

FIG. 11 shows the interrupt controller 40 of the first configuration example. The interrupt control unit can generate the interrupt signal INTF at two kinds of tone sampling periods. More specifically, a clock signal φ as shown in FIG. 13 is input to the interrupt controller. The clock signal φ is the direct output of the clock oscillator or the output after passing the output through the frequency dividing circuit. As shown in the figure, the clock signal φ is input to the lowest binary counter of the six binary counters 11-2 to 11-7 forming the ripple counter. The outputs of all binary counters 11-2 to 11-7 are input to the first OR gate 2-8, and the binary OR gate 2-9 excludes the binary counter 11-7 of the most significant bit. The outputs of the counters 11-2 to 11-6 are input. Therefore, the output of the first OR gate 2-8 becomes “0” once for the 128 basic clocks φ, and the output of the second OR gate 2-9 for the basic clock φ of 64 times 1 It becomes “0” times. The first and second OR gates 2-8 and 2-9
Which of these is to be selected may be set by program control. Therefore, there is a latch 11-1. In the case of the above-described embodiment, the latch 11-1 is set to "0" or "1" in the initial setting process A-1. That is, data "0" indicating a musical tone sampling period of 128 / fφ (fφ is the frequency of the basic clock φ) is input to a predetermined bit line of the data bus, or "1" indicating a musical tone sampling period of half the length. Command parser with the
The control signal from 38 is applied to the clock input of latch 11-1 to latch the data. The output of the latch 11-1 is the first
The output of the OR gate 2-8 is input to the OR gate 11-10, and the output of the latch 11-1 is input to the inverter 11-11.
The signal inverted by (2) is input to the OR gate 11-12 to which the output of the second OR gate 2-9 is input. OR gate 11-10
The output of the OR gate 11-12 is input to the NAND gate, and its output becomes the interrupt signal INTF. Therefore, the latch
When bit "0" is set in 11-1, the output of the first OR gate 11-8 is selected, and the interrupt signal INTF becomes active "1" once every 128 basic clocks φ and latches. When the bit "1" is set in 11-1, the output of the second OR gate 11-9 is selected, and the interrupt signal INTF becomes "1" active once every 64 base clock signals φ.

FIG. 12 shows the interrupt controller 40 of the second configuration example. This interrupt control unit can finely adjust the tone sampling period as compared with the configuration shown in FIG. Specifically, instead of the 1-bit latch 11-1, a 4-bit latch 12-1 connected to 4 bits of the data bus is used. Therefore, the microcomputer 1 uses this latch
12-1 can be set to any value from 0 to 15. The output of the 4-bit latch 12-1 is input to the B input of the comparator 12-8. A 6-bit ripple counter 12 similar to the ripple counter of FIG. 11 is connected to the A input of the comparator 12-8.
Among the outputs of −2 to 12-7, the outputs of the upper 4-bit binary counters 12-4 to 12-7 are input. The comparator 12-8 becomes "1" when the A input and the B input are equal,
Generates interrupt signal INTF. The interrupt signal INTF is also input to the reset inputs of the ripple counters 12-2 to 12-7, and resets the ripple counters 12-2 to 12-7 to all zeros when the interrupt signal INTF is generated. Therefore, in the case of the configuration shown in FIG. 12, the generation period of the interrupt signal INTF (sound sampling period) can be set to an arbitrary 8n / fφ (n = 1 to 1). For example, when the 4-bit latch 12-1 is 8 (B input = 1000)
Value of the ripple counters 12-2 to 12-7 is 1000000 (2
The interrupt signal INTF is generated every time the input signal goes to the start. That is, it is divided once for every 64 basic clocks φ. When the 4-bit latch 12-1 is 9, the rate is once for every 72 clocks φ.

Although the description of the embodiment has been completed, various modifications and changes can be made without departing from the scope of the present invention. For example,
In some applications it is conceivable to give electronic musical instruments several different musical tone synthesis capabilities. In this case, the program for each tone synthesis is stored in the program memory (control RO
M31). It is assumed that there is an optimum sampling frequency for each tone synthesis method. The user can select which tone synthesis method to use by using the mode selector switch. Therefore, the mode changeover switch is inspected on the main flow, and the selected musical tone synthesis number is set in the memory (RAM 34). Further, a table of sampling frequency data for each tone generation process (for example, placed in the control ROM 41) is accessed, data corresponding to the selected tone synthesis number is found, and set in the interrupt controller 40. When an interrupt signal is generated from the interrupt control unit 40, a table of entry points of each tone synthesis processing routine (for example, the control ROM 41
Is placed) to find the entry point corresponding to the selected musical tone synthesis number and execute the musical tone generation program starting from that position.

Other various changes are possible.

[Effects of the Invention] As described above, according to the present invention, when the microcomputer itself generates a musical sound by program control,
The tone synthesis processing is started by the signal of the interrupt signal from the timer interrupt control circuit means, and the generation period of the interrupt signal of the interrupt control means can be programmed from the microcomputer, so that the tone sampling cycle is maintained during operation. On the other hand, it is possible to generate musical tones at a musical tone sampling cycle that matches the function of the apparatus, the number of polyphonics, the method of musical tone synthesis, and the degree of processing complexity. Further, for this realization, there is an advantage that no special circuit change is required, and a highly flexible design and development of the device becomes possible.

[Brief description of drawings]

1 is an overall configuration diagram of an electronic musical instrument according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a microcomputer of the embodiment, FIG. 3A is a diagram showing a flow of a main program of the microcomputer, FIG. Fig. 3B is a flowchart of the interrupt process that generates musical tones, and Fig. 3C is
3B is a detailed flowchart of the sound source processing, FIG. 4 is a diagram showing a program flow along time, FIG. 5 is a time chart showing an outline of processing along time, and FIG. 6 is the RAM 34 of FIG. FIG. 7 is a diagram showing a table of a tone generation RAM placed inside, FIG. 7 is a detailed flowchart of one channel processing of FIG. 3C, FIG. 8 is a diagram showing an envelope, and FIG. 9 is waveform data of a waveform ROM. FIG. 10, FIG. 10 is a diagram showing interpolation calculation waveforms along time, FIG. 11 is a diagram showing a first configuration example of the interrupt control unit, and FIG. 12 is a diagram showing a second configuration example of the interrupt control unit. FIG. 13 is a time chart of the clock input of the interrupt control unit. 1 ... Microcomputer, 31 ... Control ROM, 34 ...
RAM, 35 ... Adder / subtractor and logical operation unit, 36 ... Multiplier, 37 ... Control data / waveform ROM, 38 ... Operation analysis unit, 40 ... Interrupt control unit.

Claims (2)

[Claims] 1. A program storing means for storing a program for processing an input for controlling a musical instrument and a program for generating a musical tone, an address control circuit means for controlling an address of the program storing means, and a musical tone generation. Data storage means for storing necessary data, arithmetic circuit means, and operation control circuit means for decoding each instruction of the program of the program storage means to control the operation of each means. Further, the microcomputer has a timer interrupt control circuit means for generating an interrupt signal at a sampling period of a musical sound, and a program for generating the musical sound in response to an interrupt signal from the timer interrupt control circuit means is provided. Run on a microcomputer Processing apparatus characterized by tone is generated, and further the timer interrupt control circuit can variably programmable sampling period of the musical tone is an interval in which the interrupt signal is generated in the means by which. 2. The processing device according to claim 1, wherein said microcomputer is composed of an integrated circuit chip, and a digital / analog converter for converting a digital musical tone signal into an analog signal and an input for controlling a musical instrument are provided on this chip. A processing device, further comprising a port for receiving.