JPH03242776A - Microcomputer - Google Patents

Abstract

PURPOSE:To improve the processing efficiency of a CPU by providing a microcomputer with a means for switching the contents of data to be outputted to the external at an optional timing independently of the control of a central processing unit(CPU) after setting up output data by the CPU. CONSTITUTION:The CPU 1 sets up data in a polarity setting buffer 8 through buses 3, 4 and instructs timers A, B to start counting. When the timer B starts counting, initial data are set up in a toggle flip flop(FF) 7 and then the output Q and the polarity of the outputs Q of the FF 7 is inverted in each overflow of the timer A. Thereby, the polarity of a port output can be switched at real time in response to each overflow of the timer A independently of the CPU 1. Since it is unnecessary for the CPU 1 to always set up the switching timing of port output data, delay time for switching the port output data can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microcomputer that operates various external circuits using output data from an output device.

[Conventional technology]

FIG. 3 is a block diagram showing the input/output functions of a conventional microcomputer, in which 1 is the central processing unit (
(hereinafter abbreviated as CPU), 2 is the output word! (hereinafter referred to as a port), which is connected to the CPU via an address bus 3 and a data bus 4. 5 is a peripheral circuit including a timer, serial I10. Some peripheral functions such as an A/D converter are shown.

Next, the operation when outputting via the boat will be explained. Port output is determined by the settings of the port input/output direction register and port data register.

The CPUI sets the output direction register and data register in boat 2 via buses 3 and 4. The output data of the boat is switched at the timing of this write from the CPU. Note that the port input/output direction register is for switching the input/output direction of data, and the data register is for setting data for controlling the external circuit.

[Problem to be solved by the invention]

Since the port output function of conventional microcomputers is configured as described above, port output data can only be switched by the CPU, so the CPU always operates and monitors other peripheral functions while switching the port output data. If you are responsible for performing output setting processing, or if you are switching port output when a certain peripheral function completes its operation, it will take a non-negligible amount of time to complete the port output data switching process after sensing the end of the operation. There was a problem that it was necessary.

The present invention has been made to solve these problems, and provides a microcomputer that eliminates the need for the CPU to constantly plan the timing for switching port output data, and also eliminates the delay time in switching port output data. The purpose is to provide

[Means to solve the problem]

In the microcomputer according to the present invention, after the CPU sets the output data to the output setting buffer, the port output is performed using a startup signal such as an interrupt request signal sent from a peripheral circuit without any intervention from the CPU. The configuration is such that the data in the buffer is transferred to the launch, and the port output is immediately and repeatedly inverted by the next control signal.

[Effect]

In the present invention, since the configuration is as described above, the CPU
However, once the initial value of the port output data is set, the port output is switched by starting other peripheral functions independently from the CPU control.
It is possible to invert the boat output using only the signal generated by the peripheral circuit without going through it.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a microcomputer according to an embodiment of the present invention. In the figure, 1 is a CPU, 2 is a port output circuit (input/output circuit) similar to the conventional example, and the present embodiment is A second output control circuit 6 operated by a control signal from the peripheral circuit 5 is added to this, and the output of the second output control circuit 6 and the output of the port output circuit 2 are connected to one of them by switches 9a and 9b controlled by the CPU. It is structured so that you can select.

FIG. 2 shows an example of the configuration of the second output control circuit.

Here, an example will be explained in which control signals are received from two timers A and B as peripheral circuits, and the toggle flip-flop 7, which determines the polarity (HIGH/LOW) of the output of the port control circuit 2, is controlled by the control signals. .

First, the CPUI sets data in the polarity setting buffer 8 via the bus 3.4, and instructs the timers A and H to start counting. When timer B starts counting, initial data is set in toggle flip-flop 7, and thereafter, the polarity of outputs Q and ci of the toggle flip-flop are inverted every time timer A overflows. Therefore, the boat output is independent of the CPU, and reacts in real time every time timer A overflows, making it possible to switch polarity.

In this way, according to this embodiment, the CPU does not need to constantly plan the timing for switching the output data of the port.
In addition, when switching the boat output, it reacts in real time to the operation of peripheral circuits, making it possible to control external circuits (such as motor drive control circuits) with higher precision through simpler software processing. Effects can be obtained.

By changing the count values of timer A and timer B appropriately, this microcomputer has an excellent effect on forming a sine wave.
By providing three output control circuits, it can be effectively used as an inverter motor control device.

Further, in the above embodiment, two timers B are taken as an example of the control signal source, but the control signal is not limited to this, and signals of other peripheral functions may be used.
Exactly the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the microcomputer according to the present invention, by providing the second output control circuit, CPtJ
Since port output switching can be controlled using signals issued by peripheral circuits without going through It is no longer necessary to perform control processing for port output and port output, and this time can be used for other calculations, data processing, etc., which has the effect of improving the processing efficiency of the CPU.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a microcomputer according to the present invention, FIG. 2 is a diagram showing an embodiment of the microcomputer according to the present invention, and FIG. 3 is a block diagram showing the configuration of a conventional microcomputer. . In the figure, 1 is a CPU, 2 is an input/output circuit, 3 is an address bus, 4 is a data bus, 5 is a peripheral circuit, 6 is a second output control circuit, 7 is a toggle flip-flop, and 8 is an output data setting buffer. . Note that the same reference numerals in the figures indicate the same or equivalent parts. 4j Tenita Rikio Flat Soo March 3, 1993 ILf'' Date of the Case Patent Application No. 2-40658 Name of the Invention Microcomputer 3, Relationship with the Amendment Person Case

Claims (1)

[Claims] (1) In a microcomputer that is composed of a central processing unit, peripheral circuits, and an output device, and outputs data set by the central processing unit via the output device, after the central processing unit sets the output data, A microcomputer characterized by having means for switching the content of data to be output to the outside at any timing, independent of the control of a central processing unit.