JPH0580089A - Timer device - Google Patents

Abstract

PURPOSE:To obtain a timer device which can change a set count value variously and realize the change by a minimal interrupt processing and thereby to improve an executive processing speed of a microcomputer and the like. CONSTITUTION:Set count values different from each other are stored in a plurality of reload registers 2A and 2B by a writing means 1. At the time point of receiving an overflow signal 5 as an input from a counter 3, a reload control circuit 8 specifies the register storing the set count value to be counted subsequently and reloads this value on the counter 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timer device incorporated in a microcomputer or the like.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a conventional timer device. In the figure, 1 is a writing means for writing a count set value to the reload register 2 when a write signal WR is input, 3 is a counter for counting up to the count set value stored in the reload register 2, and 4 is a count completion signal from the counter 3. Overflow signal 5 as
Is a reload signal generation circuit that outputs a reload signal 6 and 7 is a switch that reloads the count set value stored in the reload register 2 into the counter 3. The switch 7 is turned on when the reload signal 6 is input.

Next, the operation will be described. When it is desired to set the timer while the program is being executed by the microcomputer or the like, the count setting value is written from the writing means 1 to the reload register 2 by the generation of the write signal WR by using the interrupt processing function of the microcomputer or the like. The counter 3 reads the reloaded count setting value from the reload register 2 at the same time when the reload signal 6 is generated,
The count clock is counted up to that value. continue,
When the counting is completed, the overflow signal 5 is output.
The overflow signal 5 is used as an interrupt process in the microcomputer and as a signal to other devices.
The reload signal generation circuit 4 outputs the reload signal 6 when the overflow signal 5 is input, the switch 7 is turned ON at that timing, and the count set value stored in the reload register 2 is reloaded into the counter 3. The counter 3 starts counting up to the reloaded count set value again, and the above operation is repeated.

[0004]

Since the conventional timer device is constructed as described above, the interrupt processing time of the microcomputer is required when setting the timer. Therefore, when it is desired to change the count set value, the interrupt processing time is required each time, which causes a problem that the processing of the main program being executed by the microcomputer becomes slow.

The present invention has been made to solve the above problems, and even if the count set value is changed,
An object of the present invention is to obtain a timer device that enables high-speed processing of a main program such as a microcomputer.

[0006]

A timer device according to the present invention includes a plurality of reload registers for storing different count setting values, a writing means for writing the count setting values in the plurality of reload registers, and a specified reload register. A counter that counts up to the written count setting value and outputs a count completion signal, and a reload control circuit that, when the count completion signal is input, specifies one of the plurality of reload registers to reload the counter. It is equipped with.

[0007]

There are a plurality of reload registers in the present invention, and different count set values are set at one time.
Further, by changing the reload register designated by the reload control circuit, the count set value to be reloaded to the counter is changed.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1, 3 and 5 are exactly the same as those of the conventional device. 2A and 2B are reload registers for storing different count setting values, and 6A and 6B are reload signals, which are output to switches 7A and 7B for reloading the values stored in the reload registers 2A and 2B into the counter 3, respectively. Reference numeral 8 is a reload control circuit for designating one of the reload registers 2A and 2B and outputting a reload signal for turning on the corresponding switch.

Next, the operation of changing the count set value each time the counter overflows will be described.
In advance, two different count setting values to be set are stored in the two reload registers 2A and 2B by using the writing means 1. The counter 3 reads either one of the two reload registers 2A and 2B, for example, the count set value reloaded from the reload register 2A, and counts the count clock to that value. Then, when the counting is completed, the overflow signal 5 is output. The reload control circuit 8 outputs the reload signals 6A and 6B when the overflow signal 5 is input, but at this time, the count setting value different from the count setting value previously counted, for example, the count setting value stored in the reload register 2B. Reload signal 6B is made effective so that is reloaded, and switch 7B is turned on. As a result, the count set value stored in the reload register 2B is reloaded into the counter 3. That is, the counter 3 now counts up to the reload set count value from the reload register 2B.

When both of the initially set two count set values are used and then counting is performed again with different values, the writing means 1 is used at the timing of outputting the overflow signal 5 of the second count. , And two new different values are written to the two reload registers 2A and 2B, respectively. This process is an interrupt process of the microcomputer, but the setting value can be changed twice, and the interrupt process time can be halved.
When two different count setting values are alternately used each time the overflow signal 5 is generated, the reload control circuit 8 only needs to control the reload signal 6A and the reload signal 6B to be alternately valid. No interrupt processing occurs. Further, when the two count setting values are used not every time but every arbitrary number of times, or only one of them is used, it is possible only by the control of the reload control circuit 8.

Embodiment 2. It should be noted that, in the above embodiment, the one provided with two reload registers is shown, but the one provided with n (n is arbitrary) may be provided. FIG. 2 is a block diagram showing a timer device according to the second embodiment. In the figure, reference numerals 1, 3, 5 to 8 are exactly the same as those of the first embodiment. Reference numeral 9 is a reload register, and n is a register, and 10 is a register designating signal for designating which of the n reload registers is to be reloaded. In this embodiment, n count set values are stored in advance in the n reload registers 9. If the reload control circuit 8 needs to reload the value to the counter again when the overflow signal 5 is input from the counter 3, the reload signal 6 and the register designation signal 10 are output to output the designated reload register. The count set value stored in is reloaded into the counter 3.
When it is desired to set a new value, the n count setting values can be changed by one interrupt process. Further, if the reload registers can be designated in any order, n different count set values can be effectively used only by the control of the reload control circuit 8.

Embodiment 3. In each of the first and second embodiments, the counter 3 is shown as outputting the overflow signal 5 as the count completion signal. Has the same effect.

[0013]

As described above, according to the present invention, since a plurality of reload registers are provided and the count setting values in the plurality of reload registers can be arbitrarily used by the reload control circuit, various timer operations are possible. In addition, the number of interrupt processes for changing the count set value to be reloaded in the counter is reduced, and the process of the main program of the microcomputer can be speeded up.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a timer device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a timer device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional timer device.

[Explanation of symbols]

 1 writing means 2A, 2B reload register 3 counter 5 overflow signal as count completion signal 6A, 6B reload signal 8 reload control circuit

Claims (1)

[Claims] 1. A timer device built in a microcomputer or the like for counting up to a count set value written in a reload register, wherein a plurality of reload registers storing different count set values, and the count set values in the plurality of reload registers are provided. Writing means, a counter that counts up to the count set value written in the specified reload register and outputs a count completion signal, and when one of the plurality of reload registers is input when the count completion signal is input. A timer device comprising a reload control circuit for specifying and reloading to the counter.