JPH033019A - Timer - Google Patents

Abstract

PURPOSE:To reduce the load of software by allowing a counting initial value computing circuit to compute the initial value of counting to be executed next and apply the initial value to a load register. CONSTITUTION:The initial value of counting is set up in the load register 4 through a data bus 4 and then applied to a counter 3. On the other hand, an operation parameter for generating the initial value of each counting as a data string is applied to the counting initial value computing circuit 5 through a data bus 1. The circuit 5 calculates the data string or the counting initial value by using the operation parameter and sets up the calculated value in a reloading register 4. During the counting of clock pulses by the counter 3, the circuit 5 executes operation by using the applied operation parameter and applies the computed result to the register 4 as the initial value of counting to be executed next. Since the operation parameter is applied to the counting initial value computing circuit 5 only once, the load of software can be reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a timer built into a computer.

[Conventional technology]

FIG. 3 is a block diagram showing a timer 2 in a conventional computer.

In the figure, a timer 2 includes a reload register 4 and a counter 3, and an initial count value is set in the reload register 4 from the data bus I side when counting time. The initial count value set in the reload register 4 is given to the counter 3, and the counter 3 starts counting clock pulses input from a clock pulse generator (not shown) from this initial value. When the count ends, the counter 3 notifies the data bus 1 that the time limit has been reached, takes in the initial count value from the reload register 4, and counts clock pulses again.

[Problem to be solved by the invention]

However, if it is necessary to start the subsequent count from a different initial count value after the count ends,
In order for the program to set a new count initial value in the reload register 4, it is necessary to define the count initial value for each count in the program, which poses a problem in that the burden on the software becomes large.

Furthermore, when it is necessary to change the initial count value for the next sequence by an operation from outside the computer, there is a problem in that a program is required to handle the external operation.

The present invention has been made to solve such problems, and the first invention calculates the initial count value for each count and sets it in the reload register, and the second invention calculates the initial count value for each count and sets it in the reload register. It is an object of the present invention to provide a timer that reduces the burden on software by having a configuration in which an initial count value is directly set in a reload register without going through a program.

[Means for Solving the Problems] The timer of the first invention is characterized in that it includes a count initial value calculation circuit.

The timer according to the second aspect of the invention is characterized in that it includes a switching circuit that switches between a program side and an external side of the computer for setting a count initial value for a reload register.

[Operation] When the count initial value calculation circuit is given parameters for count initial value calculation, the timer of the first invention calculates the count initial value and sets the value in the reload register.

In the timer of the second aspect of the invention, when an initial count value is input by an external operation, the switching circuit operates to set this value in the reload register.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on drawings showing one embodiment thereof.

FIG. 1 is a block diagram showing the configuration of the timer 2 of the first invention. The timer 2 includes a counter 3 that counts clock pulses input from a clock pulse generator (not shown), a reload register 4 that provides a count initial value to the J counter 3, and a count initial value calculation circuit that calculates the next sequential count initial value. It is composed of 2.

The initial count value set by the program of the computer equipped with this timer 2 is the same as the conventional one.
It is set in the reload register 4 via the reload register 4, and is applied to the counter 3 from there. On the other hand, calculation parameters for generating a count initial value for each count as a data string are applied to the count initial value calculation circuit 5 via the data bus 1.

The count initial value calculation circuit 5 calculates the above-mentioned data string or count initial value a 4fL using this calculation parameter,
This is set in the reload register 4.

While the counter 3 is counting clock pulses, the count initial value calculation circuit 5 performs calculation using the given calculation parameters, and provides the result to the reload register 4 as the count initial value for the next count. When the counter 3 finishes counting, it outputs to the data bus 1 that the time limit has been reached, and the initial count value set in the reload register 4 is taken into the counter 3 in order to start the next count. Counter 3 starts counting using a new count initial value different from the count initial values of both previous counts.

Next, the timer 2 of the second invention will be explained based on FIG. 2.

This timer 2 includes a reload register 4 and a counter 3 as well as an initial count value from the data bus 1 and a peripheral circuit 8.
A switching circuit 7 is provided for switching between the initial value and the manual input. The peripheral circuit 8 is connected to the switching circuit 7 via the local bus 6.
is connected to. The peripheral circuit 8 is, for example, a to-10 converter, etc., and is connected to an external device (not shown), and is supplied with data serving as an initial count value by external operation. The switching circuit 7 switches between the data bus 1 and the local bus in order to switch between the initial count value given from the outside via the peripheral circuit 8 and the initial count value specified in the program and set it in the reload register 4. Switch between 6 and 6. When the initial count value is input to the peripheral circuit 8 by external operation while the counter 3 is counting clock pulses, the peripheral circuit 8 reports this to the switching circuit 7.

Then, the switching circuit 7 switches from the data bus 1 to the local bus 6 and sets a new count initial value in the reload register 4. The reload register 4 provides a new initial count value to the counter 3, which uses the initial count value to count clock pulses.

[Effects of the Invention] As explained above, in the timer of the first invention, the count initial value calculation circuit calculates the initial value of the next count and gives it to the reload register, so even if the initial value is different for each count, Also, the load on the software is small because the calculation parameters only need to be given once to the count initial value calculation circuit.

Further, in the timer of the second invention, since the initial count value given from the outside can be set in the reload register, no program is required to change the initial count value by external operation.

In this way, both the timers of the first and second inventions have the advantage that the initial count value can be changed without increasing the burden on software.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of a timer according to the first invention, FIG. 2 is a block diagram showing the structure of the timer according to the second invention, and FIG. 3 is a block diagram showing the structure of a conventional timer. l...Data bus 2...Timer 3...Counter 4...Reload register 5...Count initial value calculation circuit 7...Switching circuit Note that in the figures, the same reference numerals indicate the same or equivalent parts. shows.

Claims (2)

[Claims] (1) In a timer equipped with a counter that counts clock pulses and a reload register that provides an initial count value to the counter, an initial count calculation circuit that calculates the initial count value and sets it in the reload register. A timer characterized by: (2) In a timer comprising a reload register in which an initial count value specified in a program to be executed by a computer is set, and a counter that counts clock pulses from the initial count value given by the reload register, the program 1. A timer comprising a switching circuit that switches between a count initial value defined in the above and a count initial value given from outside the computer and sets the same in the reload register.