JP2695546B2 - Microcomputer built-in count source automatic change timer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention relates to a micro computer.
More specifically, the present invention relates to a microcomputer built-in count source automatic changing timer capable of automatically changing the count source of the timer.

[0002]

2. Description of the Related Art A conventional timer with a built-in microcomputer comprises a circuit as shown in FIG. In FIG. 2, 1 is a count source A input line, 2 is a count source B input line, 3 is a selection gate, 4 is a count stop / permit gate, 5 is a count stop / permit input line, and 6 is a timer.

Next, the operation will be described. When counting is performed by the count source A and the count source is changed to the count source B, the count stop signal of the timer 6 is set to "1" by software to stop the count and then the selection gate 3 is set to the count source B. It was set to the side and switched.

[0004]

Since the count source circuit of the conventional timer is configured as described above,
Even if multiple count sources can be selected, the timer count must be stopped in software, and it is impossible to change the count source without stopping the timer count in software. .

The present invention has been made to solve the above problems, and when the control is performed by switching the count source of the timer, the switching setting for setting the count value of the timer for comparison with the timer value. An object of the present invention is to provide a count source automatic changing timer with a built-in microcomputer in which a timer can automatically select a count source without stopping counting of the timer by using a register.

[0006]

SUMMARY OF THE INVENTION In a microcomputer built-in count source automatic change timer according to the present invention,
A dedicated count source switching setting means (count source switching setting register 10) for setting the count source switching value is compared with the timer value of the timer 6 and the count source switching value, and the timer value is equal to or greater than the count source switching value. If so, a first count source (count source A) is selected, and if the count value is smaller than the count source switching value, a second count source (count source B) is selected. 9) and switching means S for selecting the first count source or the second count source and outputting the selected count source to the timer according to an instruction from the comparison means.

[0007]

In the microcomputer built-in count source automatic changing timer according to the present invention, the count source switching value of the timer is set in the count switching setting register 10 in advance. The comparison means compares the timer value of the timer with the count source switching value, and if the timer value is equal to or greater than the count source switching value,
A signal is supplied from the first count source to the timer through the switching means, and the switching means is switched if the count value is smaller than the count source switching value,
A signal is supplied from a second count source to the timer via the switching means. At this time, the comparison means switches from the first count source to the second count source when the count source switching value of the count source switching register and the count value of the timer match.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit block diagram of a count source automatic changing timer with a built-in microcomputer according to an embodiment of the present invention. In FIG. 1, 1 is a count source input line of a count source A as a first count source,
2 is a count source input line of a count source B as a second count source, 4 is a count stop / permit gate, 5 is a count stop / permit input line, 6 is a timer, 7 and 8 are gates as switching means S, Reference numeral 9 is a comparator as comparison means, 10 is a count source switching setting register as count source switching setting means, 11 is a count source switching control line, 12 is a timer value signal line, and 13 is a count source switching value signal line. It should be noted that parts having the same functions as those of the conventional example of FIG. 1 are denoted by the same reference numerals as those of the conventional example of FIG.

The gates 7 and 8 are connected to the count sources A and B via the count source input lines 1 and 2, respectively,
Under the control of the comparator 9, the signals from the count sources A and B are supplied to the count stop / permission gate 4. The comparator 9 is connected to the gates 7 and 8 via the count source switching control line 11, is connected to the timer 6 via the timer value signal line 12, and is set to the count source switching setting via the count source switching value signal line 13. It is connected to the register 10. When the timer value of the timer 6 is equal to or larger than the count source switching value of the count source switching setting register 10, the gate 7 is controlled so that the timer 6 is controlled from the count source A through the gate 7 and the count stop / permission gate 4. When a signal is supplied and the timer value of the timer 6 is smaller than the count source switching value of the count source switching setting register 10, the gate 8 is controlled so that the count source B passes through the gate 8 and the count stop / permission gate 4. A signal is supplied to the timer 6. The count source switching setting register 10 is a register for presetting the count source switching value.

Next, the operation of this embodiment will be described. A count source switching value is set in the count source switching setting register 10, and the first count source is set to the count source A by controlling the gate 7 to start counting by the timer 6. The comparator 9 compares the timer value of the timer 6 and the count source switching value with the timer value signal line 1
2, the comparison is made via the count source switching value signal line 13, and when the timer value is equal to or more than the count source switching value, the count source switching control line 11 is "L".
The signal is output and the state of the count source A selection is maintained. If the timer value is smaller than the count source switching value, the count source switching control line 11
A "H" signal is output to control gate 8 to switch from gate 7 to gate 8 to select count source B. Thus, by providing the count source switching register, it is possible to automatically switch the count source of the timer at a certain set time and set timings with different resolutions.

Further, the application range of the timer in the microcomputer is expanded, and the program processing is simplified. In the above embodiment, the count source is 2
Although two cases have been described, the present invention can be applied to the case where there are multiple count sources.

[0012]

As described above, according to the present invention, the dedicated count source switching setting means for setting the count source switching value is compared with the timer value of the timer and the count source switching value, and the timer value is compared. Is equal to or larger than the count source switching value, the first count source is selected, and if the timer value is smaller than the count source switching value, a second count source is selected, and a comparing means for selecting the second count source. Since the switching means S for selecting the first count source or the second count source according to the instruction and outputting to the timer is provided, the count source of the timer is automatically selected without stopping the count of the timer. There is an effect that can be done. Also dedicated
Since it has a count source switching setting means of
Timer count before generating interrupt signal
The count source can be switched during the process. Toes
Therefore, the timer interrupt signal does not depend on
You can switch the count source by minging.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of a count source automatic changing timer with a microcomputer according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram of a timer with a built-in microcomputer showing an example of a conventional technique.

[Explanation of symbols]

 1 Count source A input line 2 Count source B input line 4 Count stop / enable gate 5 Count stop / enable input line 6 Timer 7, 8 Gate 9 Comparator 10 Count source switching setting register 11 Count source switching control line 12 Timer value signal Line 13 Count source switching value signal line S switching means

Claims (1)

(57) [Claims] 1. A first device for supplying a signal from which time is measured.
Alternatively, in a microcomputer built-in count source automatic changing timer including a second count source and a timer that operates based on these count sources,
And dedicated count source switch setting means for setting a count source switching value, compares the timer value and the count source switching value of the timer, the count value is equal to the count source switching value or more, the first If the count source is selected and the timer value is smaller than the count source switching value, the comparing means for selecting the second count source and the instruction of the comparing means
A count source automatic changing timer with a built-in microcomputer, comprising a switching means S for selecting the first count source or the second count source and outputting the selected count source to the timer.