JPH04235618A - Microcomputer system - Google Patents

Abstract

PURPOSE:To choose an optimum clock frequency and to actuate a microcomputer system with the most economical power consumption by choosing a clock frequency in accordance with the processing value end then choosing an optimum clock frequency. CONSTITUTION:A microcomputer 1 containing a clock frequency choosing means 11 is provided together with a voltage converter 2 which converts the signal outputted from the means 11 into the voltage, and a voltage control oscillator 2 which controls the oscillation frequency based on the voltage level. The means 11 sets en optimum clock frequency according to the processing value obtained in a fixed period of the microcomputer 1. Then the corresponding clock frequency is read out of a clock frequency table in response to the processing input count value that counts the number of unit processing inputs obtained within 8 fixed processing period. Thus an optimum clock frequency is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcomputer system, and more particularly to a microcomputer system with variable clock frequency.

0002

2. Description of the Related Art An example of a conventional microcomputer system is shown in FIG.
It was configured to include fixed frequency clock oscillators 5, 5.

[0003] In general, the clock frequency of a microcomputer system is fixed, so there are many external inputs such as key inputs. The microprocessor system operated at the same clock frequency even when in a standby state with no processing.

In other words, the power consumption of the microcomputer system does not change because it operates at the same clock frequency regardless of the number of processes.

[0005] Furthermore, the clock frequency of microcomputer systems such as battery-driven devices that place importance on power consumption can be adjusted by installing multiple fixed-frequency clock oscillators and switching the clock oscillators depending on the amount of processing. Power consumption was reduced.

[0006]

[Problems to be Solved by the Invention] The above-mentioned conventional microcomputer system has problems even when there are many external inputs and executes many processes, and even when there are no external inputs and no processes are executed. Because they operate at the same clock frequency, the power consumption is the same regardless of the amount of processing, so there is a drawback that power is wasted when no processing is performed.

Furthermore, in order to reduce power consumption, the frequency of the clock oscillator is fixed, so complicated operations such as converting the clock frequency oscillator or installing and switching multiple clock oscillators with different frequencies are required. was there.

[0008]

[Means for Solving the Problems] A microcomputer system of the present invention is a microcomputer system that varies a clock frequency in accordance with the amount of processing, and a frequency selection method that selects a predetermined clock frequency corresponding to the amount of processing. and a clock oscillator that oscillates the clock frequency based on the output of the frequency selection means.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to the drawings.

FIG. 1 is a functional block diagram showing a microcomputer system according to an embodiment of the present invention.

In FIG. 1, the microcomputer system of the present invention includes a microcomputer 1 including a clock frequency selection means 11;
A voltage conversion circuit 12 that converts the signal output from the
and a voltage controlled oscillation circuit that controls the oscillation frequency by voltage.

The frequency selection means 11 is for selecting the optimum clock frequency corresponding to the processing amount of the microcomputer 1 within a certain period of time. Examples of such functions include a processing input counter that counts the number of unit processing inputs within a certain processing period and outputs a processing input count value, and stores data on the optimal clock frequency corresponding to the processing input count value. There is a combination with the clock frequency table. In other words, depending on the processing input count value,
The optimum clock frequency is selected by reading the corresponding clock frequency from the clock frequency table.

Next, the operation of this embodiment will be explained.

FIG. 2 is an operational flowchart of the circuit of this embodiment shown in FIG.

First, the number of unit processing inputs within a certain period of time is counted (step S1).

Next, clock frequency data corresponding to the processing input count value is selected from the clock frequency table (step S2).

Next, data of the selected clock frequency is converted into voltage (step S3).

Next, the frequency of the voltage controlled oscillation circuit is controlled using the converted voltage (step S4).

As described above, the microcomputer system of the present invention has an optimal clock frequency selected according to the processing amount of the microcomputer, and operates with the most economical power consumption.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways.

For example, the voltage conversion circuit 2 and the voltage controlled oscillation circuit 3 are assumed to be added outside the microcomputer, but it is of course possible to include them inside the microcomputer as long as the gist of the present invention is not departed from. It is.

[0022]

As explained above, the microcomputer system of the present invention includes a frequency selection means for selecting a clock frequency according to the amount of processing, and a clock oscillator for oscillating a clock frequency based on the output of the frequency selection means. By having this, the optimum clock frequency is selected according to the processing amount of the microcomputer, and the effect is that the microcomputer operates with the most economical power consumption.

[0023] Also, there is an advantage that complicated operations such as switching between a plurality of clock frequencies are not required.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a microcomputer system of the present invention.

FIG. 2 is a flowchart showing an example of the operation in the microcomputer system of this embodiment.

FIG. 3 is a block diagram showing an example of a conventional microcomputer system.

[Explanation of symbols]

1,4 Microcomputer 2 Voltage conversion circuit 3 Voltage controlled oscillation circuit 5, 6 Clock oscillator

Claims (2)

[Claims] 1. A microcomputer system that varies a clock frequency in accordance with a processing amount, comprising: frequency selection means for selecting a predetermined clock frequency corresponding to the processing amount; and a frequency selection means for selecting a predetermined clock frequency corresponding to the processing amount; A microcomputer system comprising: a clock oscillator that oscillates a frequency. 2. The frequency selection means includes processing input counting means for calculating the number of inputs of predetermined processing unit inputs within a predetermined processing period and outputting a processing input count value, and a processing input count means corresponding to the processing input count value. a clock frequency table storing data of the clock frequency; the clock oscillator includes a voltage conversion circuit that converts the data of the clock frequency selected from the clock frequency table into a voltage; and a voltage conversion circuit that controls the frequency using the voltage. 2. The microcomputer system according to claim 1, further comprising a voltage controlled oscillation circuit.