JPH0581447A - Microcomputer - Google Patents

Abstract

PURPOSE:To prevent an unnecessary current from flowing by providing each peripheral device with a frequency divider and a clock selecting means of the fundametal clock which controls the peripheral function. CONSTITUTION:A CPU 101 to which a clock phi is inputted, a frequency divider 1021 to which the clock phi is inputted, a clock selecting means 1031 to which the output of the frequency divider 1021 is inputted, and a peripheral device 1041 to which the output of the means 1031 is inputted are provided. Further, frequency dividers 102N (N=2,3...) to which the clock phi is inputted, clock selecting means 103N to which outputs of frequency dividers 102N are inputted, and peripheral devices 104N to which outputs of clock selecting means 103N are inputted are provided. The clock 4 is inputted to the CPU 101, and required clock frequencies are selected from the clock, which has the frequency divided by frequency dividers 102N, by clock selecting means 103N and are inputted to peripheral devices 104N. An arbitrary clock is inputted to the peripheral device whose processing speed is not high, and an unnecessary current does not flow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcomputer, and more particularly to a microcomputer having a central processing unit (CPU) and peripherals.

[0002]

2. Description of the Related Art A conventional microcomputer includes, as shown in FIG.
Peripheral 4021 to peripheral 402N using clock φ as input
(N = 2, 3, ...).

Since the same clock φ is input to the CPU 401 and the peripherals 4021 to 402N, a CPU requiring a high processing speed is required even in a peripheral which does not require a high processing speed.
The same clock φ as the peripheral was input, and an extra current was flowing.

[0004]

In the above-described conventional microcomputer, a CPU requiring a high processing speed is input to a peripheral that does not operate at a high processing speed, and the same clock φ as that in the peripheral is input, and an extra current flows. . Therefore, extra power consumption is generated, which affects the destruction and life of the microcomputer. Furthermore, the increase in self-heating also adversely affects other devices.

An object of the present invention is to solve the above problems and to provide a microcomputer in which an extra current is prevented from flowing and high reliability is ensured.

[0006]

According to the structure of the present invention, in a microcomputer having one CPU and a plurality of peripherals, a basic clock frequency divider and a clock selecting means for controlling the peripheral functions are provided in the peripherals. It is characterized by having.

[0007]

1 is a block diagram showing a microcomputer according to a first embodiment of the present invention.

Referring to FIG. 1, the first embodiment of the present invention is as follows.
CPU 101 that receives clock φ, frequency divider 1021 that receives clock φ, clock selection means 1031 that receives the output of frequency divider 1021, and means 1031
1041 that receives the output of
Frequency divider 102N (N = 2, 3, ...) Having the input and clock selecting means 10 having the output of the frequency divider 102N as the input
3N and a peripheral 104N to which the output of the clock selection means 103N is input.

FIG. 2 is a waveform diagram showing a clock divided by the divider of FIG.

In FIG. 2, clock φ is φ / 2, φ
Clock selection means 1031 to 10
By selecting with 103N, the cycle of the CPU 101 and the peripheral 104N (N = 1, 2, ...) Can be taken.

Next, the operation will be described with reference to FIG. 1. The clock φ is input to the CPU 101. To the peripheral 104N, the clock divided by the frequency divider 102N is used by the clock selecting means 103N to select a required clock frequency, and the selected clock is input.

As a result, an arbitrary clock is input to the periphery where the processing speed is not high, and an extra current can be prevented from flowing.

FIG. 3 is a block diagram showing a microcomputer according to the second embodiment of the present invention.

In FIG. 3, this embodiment is provided with a stop function 301 for the CPU and further a stop function 30.
Reference numerals 31 to 303N are stop functions for the respective peripherals, and other configurations are the same as those in the first embodiment.

Here, the CPU, which is not used at all, and each peripheral are stopped by the stop function so that no current flows. If the CPU to be used and the peripherals are the same as in the first embodiment, the power consumption can be further reduced.

[0016]

As described above, according to the present invention, the basic clock divider and the clock selecting means for controlling the peripheral functions are provided in the periphery.
An arbitrary clock is input to the periphery that does not require a high processing speed, which has an effect that an extra current can be prevented from flowing.

[Brief description of drawings]

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

FIG. 2 is a waveform diagram showing an example of a clock divided by the divider of FIG.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a conventional micro-computer.

[Explanation of symbols]

101, 302, 401 CPU 1021, 102N, 3041, 304N, 4021
402N frequency divider 1031, 103N, 3051, 305N clock selecting means 1041, 104N, 3061, 306N, 4021
402N peripheral 301,3031,303N Stop function

Claims (1)

[Claims] 1. A microcomputer having one central processing unit and a plurality of peripherals, characterized in that each of the peripherals is provided with a basic clock frequency divider for controlling the peripheral functions and a clock selecting means. Microcomputer.