JPS6024968B2 - timer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a timer device that is a combination of a timer configured in hardware and a timer implemented in software.

Various timers are used in input/output control devices such as central processing units or magnetic tape control devices.

Conventionally, this timer device is a software timer that counts clocks by the micro program itself and raises a carry signal to notify the outside when it reaches a certain value.
By giving only a start command from the microprogram, subsequent processing is performed using a hardware timer that counts clocks and notifies that the carry signal has risen. A timer that is completely processed by a program counts the clock and increments it by 11, monitors whether a certain value has been reached by branching, and if it has not reached a certain value, returns to the original routine, etc., depending on various conditions. There are many operations that branch into each routine.

Furthermore, if a counting operation is performed during a period in which the main program is executing complex processing, there are various restrictions on the program. In addition, as shown in Figure 1, timers processed by hardware require a considerable amount of hardware because they combine multiple counters CTR or decoders to create a slow time. becomes larger.

Since the central processing unit or input/output control unit requires several types of timers, it is desirable to make the timer device as small as possible and obtain a high-performance timer device without imposing restrictions on complex program processing. .

An object of the present invention is to provide a timer device that is compact, has high performance, and does not restrict the original main program processing, incorporating the advantages of hardware and software, in order to satisfy such demands. be. The present invention provides a counter whose initial value is set and whose clock is changed by a microprogram, a carry register which is set by a carry signal of the counter and reset by a microprogram, and a set output of the carry register. This is a timer device provided with a micro program counter for counting by a micro program, and an embodiment thereof will be described below with reference to the drawings.

FIG. 2 is a block diagram of a timer device according to the present invention, and FIG. 3 is an operation flow chart of FIG.

As shown in FIG. 2, in the present invention, a counter CTR and carry registers CR and RG are provided as hardware.

Counter CTR is controlled to start and stop by a microprogram, and the period of clock CLK input to counter CTR is also changed by the microprogram. Counter CT by micro program
Set the initial value of R and start the counting operation. When a carry CR appears in the counter CTR (for example, an 8-bit counter), the next stage carry register CR/R
Counter CTR continues to count up even when G is set and the registers CR and RG are set.

The program can also be notified when the Carry Regis CR/RG is set.

While the hardware is performing the counting operation, the program performs more complex work, and when the program is finished, it is enough to look at the contents of the carry registers CR and RG.

That is, if the program recognizes the contents of the register CR/RG before the next carry CR goes up, it is theoretically possible to count the time. In this case, strictly speaking, a delay time occurs, but it can be corrected by increasing the number of times the program refers to the registers CR and RG to cover the number of times the carry CR goes up. Register CR/R in micro program
By referring to the contents of G, the micro program counter counts the number of times Carry-CR has risen. The microprogram looks at the contents of registers CR and RG, and if carry CR is up, it recognizes this and then resets registers CR and RG.

The flow of operation will be explained with reference to FIG. First, free
After presetting the initial value to the counter CTR in the run state (LPST) and resetting the carry registers CR and RG, start the counter CTR.
(RG RST, CTRSTA).

While performing other processing, carry registers CR/R
Look at the contents of G (RG="1"). Until it becomes “1”,
Repeat this. When the contents of registers CR and RG become “1”, reset registers CR and RG (RGRST
). The memory area is used to count the number of times the carry CR has risen (i=i+1). The operation is repeated until the count value i reaches a certain constant value N, and when it reaches N, it is read out. Note that when changing the clock mode in a program, the clock is made faster in places where the time is relatively fast or where there is a little variation, and the microprogram frequently refers to registers CR and RG.

Also, if it is rough and requires a long time, the clock should be slowed down. In this way, even with the same counter CTR, the counting time can be changed significantly by changing the clock interval.

In addition, the time can be divided into even more finely by changing the initial value.

As described above, according to the present invention, by combining a hardware timer and a software timer, for example, up to the order of ms can be counted by hardware, and beyond that can be counted by software, and a simple circuit can be realized. Depending on the configuration, long-term counting is possible.

Further, since the counting can be performed while the program executes complex processing, and the counting area of the micro program is small, there are no restrictions. Furthermore, since the timer device can be made smaller, the effect will be great if it is applied to a processing device that incorporates many types of timers.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional hardware timer, FIG. 2 is a block diagram of a timer device showing an embodiment of the present invention, and FIG. 3 is an operation flow chart of FIG. CTR: Counter, CLK: Clock, INL: Initial value setting, CR: Carry, CR/RG: Carry register, RST: Reset signal, STA: Start, PST
:preset. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A counter whose initial value is set and whose clock is changed by a micro program, a carry register which is set by the carry signal of the counter and reset by the micro program, and a set output of the carry register by the micro program. A timer device characterized by having a micro program counter for counting.