JPH02236691A - One-chip microcomputer device - Google Patents

Abstract

PURPOSE:To decrease the terminals of an IC by using the external input terminal and clock input terminal of a timer circuit in common. CONSTITUTION:An oscillator (for example, the oscillator for a clock) 2 other than a system clock, a clock input terminal 3, a clock output terminal 4, and a timer circuit 5 are provided. When the timing clock is obtained, a liquid crystal oscillator, etc., are added to clock input/output terminals 3 and 4 to the outside of the IC. At such a time, the terminal 3 functions as the clock input terminal. When the oscillator is not added to the outside, the terminal 3 functions as the input terminal to count an event from the outside of the timer circuit 5. Thus the terminals of the IC are decreased, and manufacturing costs are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a one-chip microcomputer device having a clock input terminal and a timer circuit.

[Conventional technology]

FIG. 2 is a block diagram of a conventional microcomputer device. In the figure, (1) is a microcomputer device;
(2) is an oscillator other than the system clock, (3) is a clock input terminal, and (6) is an external input terminal of the timer (5).

a clock input terminal (3) input to the oscillator (2);
An external input terminal (6) of the timer (5) was provided separately to count events input from outside the IC.

[Problem to be solved by the invention]

Conventional one-chip microcomputer devices were configured as described above, but the problem was that the limited terminals of the IC were not used efficiently, resulting in an increase in the number of IC terminals and higher manufacturing costs. there were.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to reduce the number of terminals of an IC by using both a clock input terminal and an external input terminal of a timer.

[Means to solve the problem]

The one-chip microcomputer device according to the present invention uses both a clock input terminal and a timer external input terminal.

[Effect]

Since the one-chip microcomputer device of the present invention uses both a clock input terminal and a timer external input terminal, the number of IC terminals can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is a one-chip microcomputer device, . (2) is an oscillator other than the system clock (for example, a clock oscillator), (3) is a clock input terminal, (
4) is a clock output terminal, and (5) is a timer circuit.

Next, the operation will be explained. When obtaining a clock for a watch, connect a crystal oscillator, etc. to the clock input/output terminal (
3) # Add to (4). At this time, terminal (3) functions as a clock input terminal. When no external oscillator is added, the terminal (3) functions as an input terminal for counting external events of the timer circuit (5).

〔Effect of the invention〕

As described above, according to the present invention, since one terminal is provided with two functions, the number of terminals of the IC can be reduced, and manufacturing costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a one-chip microcomputer device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional one-chip microcomputer device. In the figure, (1) is a one-chip microcomputer, (2) is an oscillator other than the system clock, (3) is an external terminal for clock input, (4) is an external terminal for clock output, and (5) is a timer circuit. . In addition, the same symbols in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] A one-chip microcomputer device having a clock input terminal other than a system clock and a timer circuit, characterized in that an external input terminal of the timer circuit and the clock input terminal are used together.