JPH0573296A - Microcomputer - Google Patents

Abstract

PURPOSE:To easily realize the waiting processing by providing a time setting circuit to set the weight time by a program instruction and a control means to control the updating stop of a program counter by a timing means and the condition of the timing means at the waiting time. CONSTITUTION:A time timing means 4 starts the timing immediately after an arbitrary waiting time is set to a time setting circuit 3 by a program instruction. A comparing circuit 5 compares the content of the time timing means 4 and the content of a time setting circuit 3, and at the time of coincidence, outputs a high level signal and at the time of non-coincidence, outputs a low level signal. An AND circuit 6 performs the AND of the output and a clock signal to update a program counter 2 to the comparing circuit 5 and outputs the result to the program counter 2. Then, by setting an arbitrary waiting time to the time setting circuit 3 by the program instruction, the updating of the program counter 2 can be stopped, and the waiting processing of the arbitrary time can be easily realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcomputer.

[0002]

2. Description of the Related Art Generally, a microcomputer executes an instruction stored in an address of a program memory indicated by a program counter, and updates the program counter after the instruction is executed.

Conventionally, in a system using a microcomputer, when performing wait processing by a program instruction (for example, in order to reliably perform key input during key input processing, a key scan signal is output and a return signal is received. In the meantime, when performing wait processing for several tens of microseconds, or in a program using a software timer that makes time according to the number of instruction steps to be executed, if there is a difference in the number of steps to be executed due to conditional branch When using wait processing to adjust the number of instruction steps), increase / decrease instructions, branch instructions and NOP
It is realized by a combination of (NoOperation) commands.

[0004]

In the above-mentioned conventional microcomputer, when the wait processing is performed by the program instruction, the increase / decrease instruction, the branch instruction and the NOP (No
Since it is performed by a combination of (Operation) instructions, there are drawbacks that the amount of program memory used increases and the execution step (execution time) of the program must be calculated.

Therefore, an object of the present invention is to solve the above drawbacks and to provide a microcomputer capable of easily realizing wait processing.

[0006]

The configuration of the present invention includes a program memory and a program counter, and has a function of executing an instruction stored at an address of the program memory indicated by the program counter. In the microcomputer, a time setting circuit for setting an arbitrary wait time by a program command, a time measuring means for measuring the wait time, and a control means for controlling update stop or update of the program counter according to a time measuring state of the time measuring means. And is provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a microcomputer according to a first embodiment of the present invention. In FIG. 1, the first embodiment is such that a program memory 1 for storing an instruction for operating a microcomputer, a program counter 2 for indicating an address of the program memory 1, and an arbitrary wait time data by the program instruction. A time setting circuit 3 to be set, a time measuring means 4 for measuring a wait time, a comparison circuit 5 for comparing the contents of the time setting circuit 3 and the contents of the time measuring means 4 and outputting a coincidence signal, and a comparison circuit 5. And an AND circuit 6 for performing a logical operation on the coincidence signal and the clock signal, and outputting the operation result.

The time counting means 4 starts counting immediately after setting an arbitrary wait time in the time setting circuit 3 by a program command. The comparison circuit 5 uses the time counting means 4
And the contents of the time setting circuit 3 are compared, and a high level signal is output if they match, and a low level signal is output if they do not match. The AND circuit 6 performs a logical product of the output to the comparison circuit 5 and the clock signal for updating the program counter, and outputs the result to the program counter 2.

Therefore, by setting an arbitrary wait time in the time setting circuit 3 by a program instruction, the update of the program counter can be stopped and the wait processing for the arbitrary time can be easily realized.

The present embodiment is a case where an AND circuit is used for the logic circuit, and can naturally be applied to other logic circuits.

FIG. 2 is a block diagram showing a microcomputer according to the second embodiment of the present invention.

In FIG. 2, the present embodiment is a case where the down counter circuit 8 is used as the time counting means, and can naturally be applied to other counter circuits. The microcomputer of this embodiment includes a program memory 1 for storing instructions for operating the microcomputer,
Depending on the states of the program counter 2 indicating the address of the program memory 1, the down counter circuit 3 for setting arbitrary wait time data by a program instruction and measuring the wait time, and the down counter circuit 8, The program counter 2 is provided with a program counter control means 9 for controlling the stop or update of the program counter 2.

The down counter circuit 8 starts time counting before and after setting an arbitrary wait time by a program instruction, and stops when it underflows. The down counter circuit 8 outputs a program counter stop signal to the program counter control means 9 during the time counting operation and a program counter operation signal during the time counting operation stop. The program counter control means 4 controls the update stop or update of the program counter 2 depending on the state of the down counter circuit 8.

Therefore, by setting an arbitrary wait time in the down counter circuit 8 by a program instruction,
The update of the program counter can be stopped, and the wait processing for an arbitrary time can be easily realized.

In particular, in the microcomputer of the first embodiment, in addition to the above-mentioned conventional microcomputer, a time setting circuit for setting an arbitrary wait time by a program command, a clock means for clocking the wait time, and a clock. The program counter is provided with a control means for stopping or updating the update depending on the state of the means.

By doing so, it becomes possible to easily implement the wait processing without combining the instructions when performing the wait processing by the program instruction.

[0018]

As is apparent from the above description, according to the microcomputer of the present invention, when the wait processing is executed by the program instruction, the usage amount of the program memory is increased or the execution step (execution time) of the program is executed. There is an effect that the wait process can be easily realized without the process of having to calculate.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a microcomputer of a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 program memory 2 program counter 3 time setting circuit 4 time measuring means 5 comparison circuit 6 AND circuit 8 down counter circuit 9 program counter control means

Claims (1)

[Claims] 1. A microcomputer comprising a program memory and a program counter, and having a function of executing an instruction stored at an address of the program memory indicated by the program counter, an arbitrary wait depending on the program instruction. A microcomputer comprising: a time setting circuit for setting a time, a time measuring means for measuring the wait time, and a control means for controlling an update stop or an update of the program counter according to a time measuring state of the time measuring means. ..