JPH064173A - Clock signal supply method - Google Patents

Abstract

PURPOSE:To attain the miniaturization and low cost of electronic equipment by generating a clock signal by the software of an MPU, and supplying a clock to the electronic equipment. CONSTITUTION:An original oscillation signal B with high accuracy is supplied from an oscillation source 9 to a signal processing unit 5, and the signal processing unit 5 performs timer interrupt processing based on the original oscillation signal B. The timer interrupt processing is executed at constant period. A signal oscillating periodically can be generated by inverting the signal state of an output port 6 at every such interrupt period. An inversion signal is supplied to another device as the clock signal CLK.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of supplying a clock signal, and more specifically to an MPU (Micro Processing Unit).
) Or the like for supplying a clock signal to an electronic device controlled by a signal processing unit.

[0002]

2. Description of the Related Art Conventionally, electronic devices such as keyboards have been
Devices that require speakers and communication ICs are often used. FIG. 6 is a block diagram showing a conventional method of generating a clock signal for an electronic device. As shown in FIG.
A special oscillation circuit 1 including an oscillation IC is provided to generate a clock signal, the MPU 2 controls the oscillation / stop of the clock through the NAND gate 3, and supplies the clock to the device 4 that requires the clock. .

[0003]

As described above, conventionally, a circuit (hardware) for oscillation is required separately from the MPU, the circuit board is large, and the number of parts is large.

However, electronic equipment is becoming smaller and less expensive year after year, the size of the circuit board is limited, and the circuit itself must be made smaller by downsizing or deletion. It is an object of the present invention to provide a method of supplying a clock signal to an MPU electronic device without separately providing an oscillation circuit.

[0005]

In order to achieve the above object, the present invention provides a signal processing unit (5) capable of performing interrupt processing at regular intervals based on an original oscillation signal (B) from an oscillation source (9). ) And another device (4) controlled by the signal processing unit (5) and operating in synchronization with a clock signal, the clock signal supplying method in an electronic circuit device, the signal processing unit (5) The output signal state of any output port (6) is inverted based on the interrupt processing cycle, and the inverted signal is supplied as the clock signal (CLK) of the other device.

[0006]

According to the present invention, the signal processing unit (5) is supplied with the highly accurate original oscillation signal (B) from the oscillation source (9), and the signal processing unit (5) receives this original oscillation signal (B). ), The timer interrupt processing is performed. This timer interrupt process is executed at a constant cycle. A signal that periodically oscillates is generated by inverting the signal state of the output port (6) every interrupt period. This inverted signal is supplied to the other device (4) as a clock signal (CLK).

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention. Here, a clock having a constant cycle is generated from the oscillation port 6 using the timer interrupt function included in the software of the MPU 5. This timer interrupt function is a crystal oscillator (XTA) externally attached to the MPU5.
L) is a function that can generate an interrupt on the software of the MPU 5 based on the original oscillation signal B from the oscillation source 9 using an oscillator with high accuracy, and many MPUs. This is a function included in. That is, with the software of MPU5, RO in MPU5
The timer interrupt routine stored in M is called at regular intervals and the output state of the oscillation port is inverted to generate the clock signal CLK. in this way,
Since the output port is controlled by software, any output port can be selected as the oscillation port.

FIG. 2 shows a flowchart of this timer interrupt routine. This timer interrupt interval is MP
Since the setting is made by the software of the MPU 5 based on the original oscillation signal B from the oscillation source 9 of U5, an accurate frequency can be obtained. Further, the set value of the timer can be arbitrarily set to some extent by the software of the MPU 5, so that the frequency can be changed.

In the circuit of FIG. 1, this clock signal CLK
Is always generated and supplied to one input terminal of the NAND gate 7. The enable signal A is supplied from the control port 8 of the MPU 5 to the other input terminal of the NAND gate 7 to control clock oscillation / stop. In this way, by controlling the input condition of the NAND gate 7 by the enable signal A, the supply / stop of the clock signal CLK can be controlled.

FIG. 3 is a block diagram showing a second embodiment of the present invention. In this example, when the MPU 5 further has a timer interrupt disable (mask) function, the interrupt in the MPU 5 software is disabled by using the function.
Oscillation / stop of the clock signal CLK is controlled by releasing the prohibition. That is, by controlling the generation of the clock signal CLK in the interrupt disabled state after the interrupt is disabled and the clock signal CLK generated in the interrupt disabled state after the interrupt disabled, the NAND as shown in FIG. It is also possible to realize a circuit that does not pass through the gate. Also in this case, similarly to the first embodiment, the setting value of the timer can be arbitrarily set to some extent by the software of the MPU 5 to change the frequency.

FIG. 4 is a block diagram showing an example of application of the present invention to a speaker. Here, the clock signal CLK obtained according to the present invention is supplied from the oscillation port 6 of the MPU to the amplifying transistor Q, the amplitude of the clock signal CLK is amplified to such an extent that the speaker SP can be driven, and then supplied to the speaker SP. is doing. The diode D is inserted between both terminals of the speaker SP in order to absorb the surge. In this circuit arrangement, the tone color of the speaker can be changed by arbitrarily changing the interrupt routine calling cycle by the software of the MPU 5.

FIG. 5 is a block diagram showing an example of application of the present invention to an IC clock for asynchronous or synchronous serial communication. Here, 8-bit data for transmission / reception is supplied from the MPU 5 to the communication IC 10, and the clock signal CLK obtained by the present invention is supplied from the oscillation port 6 of the MPU 5 to the communication IC 10. In addition, the communication IC T
The xD (for transmission) terminal transmits data to another receiver, and the RxD (for reception) terminal receives data from another transmitter. Also in this case, the data transfer rate can be changed by changing the frequency of the oscillation clock by the software of the MPU as in the case of the application to the speaker.

[0013]

According to the present invention, a speaker and a communication IC
It is possible to supply an accurate clock signal to the circuit and the like without providing a special oscillation circuit. As a result, it is possible to reduce the size of the circuit board and the number of parts, and also to reduce the size and cost of the electronic device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a flowchart of a timer interrupt routine.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing an application example of the speaker of the present invention.

FIG. 5 is a block diagram showing an example of application of the present invention to an IC clock for asynchronous or synchronous serial communication.

FIG. 6 is a block diagram showing a circuit for implementing a conventional clock signal generation method for electronic equipment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oscillation circuit 2 ... MPU 3 ... NAND gate 4 ... Device requiring clock 5 ... MPU 6 ... MPU oscillation port 7 ... NAND gate 8 ... MPU control port 10 ... Oscillation source A ... Enable signal B ... Original oscillation signal CLK ... Clock signal

Claims (1)

[Claims] 1. A signal processing unit (5) capable of performing interrupt processing at regular intervals based on an original oscillation signal (B) from an oscillation source (9), and a clock signal controlled by the signal processing unit (5). A method for supplying a clock signal in an electronic circuit device, comprising: another device (4) which operates in synchronization with the output signal of the signal processing unit (5).
Output signal state is inverted based on the interrupt processing cycle, and the inverted signal is applied to the clock signal (CL
K) is supplied as a clock signal supply method.