JPH0325519A - Timer control method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a timer control method used in a microcomputer application device that controls a plurality of timers by using a built-in timer provided inside a microcomputer.

[Prior Art] When performing timer control using a built-in timer provided inside a microcomputer, generally FRC (F
ree Runnlng Counter) and OCR (
Output Compave Register).

That is, the FRC is a register that is regularly incremented (added) by a count of "1" by the microcomputer system clock generated by a crystal oscillator in the microcomputer application device. When performing timer control, an arbitrary value for obtaining a constant timeout period is set in the OCR, and the built-in timer is activated.

FRC is regularly incremented by "1" by the system clock and compared with OCR each time. If the value of FRC matches the value preset in OCR, the microcomputer determines that the built-in timer has timed out, and executes a timeout processing program.

By the way, in timer control using built-in timers in conventional microcomputer application devices, it has been possible to control only as many timers as the built-in timers provided inside the microcomputer. That is, it was not possible to control more timers than the number of built-in timers.

[Problems to be Solved by the Invention] As described above, when a conventional configuration is configured to perform timer control using a built-in timer inside a microcomputer, the number of timers to be controlled is limited to the number of built-in timers. There was a problem.

The present invention has been made in view of the above points, and provides a microcomputer application device that performs timer control using a built-in timer.
The purpose of this invention is to provide a timer control method that enables the following.

[Means for Solving the Problems] In other words, the present invention provides a system that each time a built-in timer provided inside a microcomputer times out at a certain period,
For example, start a timer interrupt processing program stored in ROM, and decrement (subtract) by 1 the value in the counter area, which is set with a value corresponding to the timeout period specific to each timer in the timer management table (TMB). C,
As a result, the timer whose counter value reaches rOJ is determined to have timed out.

[Operation] According to the above structure, the timer interrupt processing program starts the timeout processing program for the timer that is determined to have timed out. Then, the activated timeout processing program performs timeout processing, thereby making it possible to perform timer control on a plurality of timers using one built-in timer.

[Embodiment] Hereinafter, a timer control method according to an embodiment of the present invention will be described with reference to the drawings.

First, the configuration of the microcomputer application device will be explained with reference to FIG. 1 and FIG. M2. The microcomputer application device gl11 includes a CPU 22 that controls the entire device;
Crystal oscillator 2 that generates the system clock for the CPU 22
1. Control program 24 for starting the CPU 22
, an internal register 23, and a control memory section 25.

The control program 24 is stored in a ROM, for example, and includes a main program 24a1 a timer start processing program 24b1 a timer stop processing program 24c.
5 interrupt processing program 24d1 timeout processing program for timer 1 24e1 timeout processing program for timer 2 24f1 timeout processing program for timer 3 24g. Among these, the main program 24a is a timer start processing program 2 when a start request or stop request for each timer 1, 2.3 is generated.
4b1 timer stop processing program 24c is started. The timer start processing program 24b1 and the timer stop processing program 24c are configured to pass each control to the main program 24a when the start and stop processing for one timer is completed. The interrupt processing program 24d is activated when the built-in timer in the CPU 22 (microcomputer) times out.

The control timer section 25 also includes a management table (hereinafter referred to as TMB) configured in RAM, for example.
block). This T
MB is a table that manages the start, stop, and timeout of each timer 1.2.3, and includes the counter area and initial area 7 (25a to 25f) for each timer 1 and 2.3.
).

As shown in FIG. 2, counter areas 25a, 25c,
25e, when a timer start request occurs,
The timer activation processing program 24b sets the initial value areas 25b, 25d, . 25f
The value of is copied.

Counter areas 25a, 25c, and 25e contain an interrupt processing program 2 that is activated when the built-in timer times out.
4d, each count is decremented by "1".

Here, initial value area 25b. 25d. The value of 25f is
Initial settings are made by the main program 24a according to the timeout period of each timer 1, 2.3. That is, for example, the timeout period of the built-in timer in the CPU 22 is lms.
As ec, timeout period 10msec, 20ms
ec, 30msec timer, the initial value areas 25b, 25d. 25f
The values of 10.20 and 30 are initially set in the main program 24a.

In addition, the timeout processing programs 24e, 24f, and 24g of each timer 1.2.3 are executed by the corresponding timer 1.
, 2.3 count area 25a. 25c and 25e are “
0'', they are individually activated by the interrupt processing program 24d, and when the timeout processing ends, each control is passed to the interrupt processing program 24d.

The internal register 23 is FRC (Free Run
nlngCounter) 2 3 a SO C R
(Output Compare Register)
The FRC 23a is a register that is regularly incremented by the system clock of the CPU 22 generated by the crystal oscillator 21. The OCR 23b includes an interrupt processing program 24.
In the d1 timer activation processing program 24b, an arbitrary value is set to obtain a constant timeout period when starting the built-in timer.

The FRC 23a is regularly incremented by the system clock and compared with the OCR 23b each time.

If the value of the FRC 23a matches the value preset in the OCR 23b, the CPU 22 determines that the built-in timer has timed out, and starts the interrupt processing program 24d.

Through such a procedure, the CPU 22 generates a timeout period for the built-in timer.

Next, the flow of processing of a microcomputer program that implements the timer control method of the present invention will be explained with reference to the flowcharts shown in FIGS. 3 to 5.

In the main program 24a, each timer 1, 2.3
If a startup request occurs for main program 2,
4a starts the timer start processing program 24b.

As shown in FIG. 3, the timer activation processing program 24b determines which of timers 1, 2.3, a activation request has been made (steps 100 to 10).
2). Then, according to the timer, the control memory section 2
The initial values set in the initial value areas 25b, 25d, and 25f in the counter areas 25a, 25c, and 25e
(Steps 103 to 105).

Furthermore, an arbitrary value is set in the OCR 23b of the internal register 23 to obtain a constant timeout period, and the FR
C23a is cleared rOJ, the built-in timer in the CPU 22 is activated, and a timer interrupt due to a timeout of the built-in timer is accepted (step 106). After the above processing is completed, control is passed to the main program 24a.

In the main program 24a, each timer 1, 2.3
If a request to stop occurs, main program 2
4a starts the timer stop processing program 24c.

As shown in FIG. 4, the timer stop processing program 24c determines which timer among timers 1, 2.
2). Then, according to the timer, counter area 2
The counter values in 5a, 25c, and 25e are cleared to "0" (steps 203 to 205).

Furthermore, counter area 2 corresponding to timer 1.2.3
Check whether the counter values in 5a, 25c, and 25e are rOJ (step 206), and if they are all "0", clear the OCR23b and FRC23a of the internal register 23 to "0", stop the built-in timer, and Timer interrupts due to timer timeout are prohibited (step 207).

After the above processing is completed, control is passed to the main program 24a.

On the other hand, this is a timer interrupt process that is started when the built-in timer of the interrupt process program 24d1 times out.

The interrupt processing program 24d first checks whether the counter value in the counter area 25a corresponding to timer 1 is "0" (step 300).

Here, if the counter value is not rOJ, the counter value in the counter area 25a is decremented by "1" (step 301), and it is checked whether the counter value has become "0" (step 302). Counter value is "0"
If so, timer 1 is determined to have timed out,
The timeout processing program 24e of the timer 1 is sub-called (step 303).

Below, timer 2. The same processing as that for timer 1 is performed for timer 3 as well (steps 304 to 311).

After completing the processing for each timer 1, 2.3, counter areas 25a, 2 corresponding to each timer 1, 2.3
It is checked whether the counter values in 5c and 25e are "0" (step 312), and if the above counter values are all "0",
Set FRC23a and OCR23b of internal register 23 to “0”.
” is cleared to stop the built-in timer and prohibit timer interrupts due to built-in timer timeout (step 314).
).

On the other hand, if all the above counter values are not "0", the OC
An arbitrary value that obtains a constant timeout period is set in R23b, FRC23a is cleared to "0", the built-in timer is activated, and a timer interrupt due to a timeout of the built-in timer is accepted (step 313).

In this way, multiple timers can be controlled by software processing one built-in timer using the block diagram. Therefore, even if the number of timers is greater than the number of built-in timers, it can be controlled.

[Effects of the Invention] As described above, according to the present invention, in a microcomputer application device that performs timer control using a built-in timer, by software processing one built-in timer by a program in the microcomputer application device, , multiple timer control can be performed, and the built-in timer can be used effectively.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of a microcomputer application device according to an embodiment of the present invention, FIG. 2 is a diagram showing table access in the embodiment, and FIGS. 3 to 5 are diagrams showing the same implementation. 12 is a flowchart for explaining an example operation. 11... Microcomputer application device, 21...
Crystal oscillator, 22°...CPU, 23...Internal register, 24...Control program, 25...Control memory section. Figure 1

Claims (1)

[Scope of Claim] A microcomputer application device that controls multiple timers using a built-in timer provided inside a microcomputer, which has a built-in timer that times out at a constant cycle and a timeout cycle that can be set arbitrarily. A table having a plurality of timers and a plurality of counter areas in which values are set according to the timeout period specific to each timer, and each of the above counter areas in the table each time the built-in timer times out at a fixed period. A timer control method characterized by comprising a subtraction means for subtracting the value of , and a timeout processing means for executing timeout processing of the timer corresponding to each of the counter areas whose count has become "0" by the subtraction means. .