JPH01276216A - Activating device for oscillation stability waiting circuit - Google Patents

Abstract

PURPOSE:To shorten a reset time from a trouble by operating an oscillation stability waiting circuit in synchronizing to a power source rise. CONSTITUTION:After the power source rise, a reset input 7 is made into a reset canceling condition, and an oscillation stability waiting circuit 3 starts an action when the reset input 7 is in the reset canceling condition and, simultaneously, a flag 2 is '1'. When the trouble is generated due to any factor and the reset needs to be applied, since the flag 2 is cleared, the oscillation stability waiting circuit 3 does not start the action even when the reset input 7 is reset- canceled, and it can go into an ordinary action as it is. Since the power source is in a condition to already rise and an oscillation is stable, a problem does not exist even when an oscillation stability wait is not executed. Thus, the reset time from the trouble after a self-excitation oscillation stability can be shortened.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a starting device for a self-oscillation stabilization wait circuit of a single-chip microcomputer incorporating a self-oscillation circuit, or a microprocessor incorporating the same circuit. It is related to.

2. Description of the Related Art In recent years, self-oscillation stabilization wait circuits have come to be used to ensure stable operation of single-chip microcomputers and microprocessors. The activation of the conventional self-oscillation stabilization wait circuit will be described below.

FIG. 3 is a starting timing diagram of a conventional oscillation stabilization wait circuit. When the reset terminal is reset after the power is turned on, the oscillation stabilization wait circuit is activated in synchronization with the reset release. The oscillation stabilization wait circuit is usually configured with a counter and counts a certain period of time, and is designed to count the time required for the oscillation to become sufficiently stable.

After the oscillation stabilizes, normal operation begins. However, if for some reason during normal operation the reset pin has to be reset enabled to initialize the microcomputer or microprocessor, the power supply has already been turned on and the oscillation stops. Even though it was stable, the oscillation stabilization wait circuit was activated in synchronization with the reset release.

Problems to be Solved by the Invention However, in the conventional configuration described above, even though oscillation is stable, the oscillation stabilization wait circuit operates, and it takes time to restart not only the microcomputer or microprocessor itself, but also the system itself. It had some problems.

The present invention solves the above conventional problems, and is an oscillation stabilization wait circuit that can quickly restart the initialization operation after self-oscillation stabilization and shorten the recovery time from a failure. The purpose is to provide a starting device for

Means for Solving the Problems In order to achieve this object, the oscillation stabilization wait circuit starting device of the present invention has a configuration that activates the oscillation stabilization wait circuit in synchronization with power-on.

Effect: With this configuration, the oscillation stabilization wait circuit operates only when power is turned on when self-excited oscillation stabilization is absolutely necessary, and the oscillation stabilization wait circuit does not operate when oscillation stabilization wait after oscillation stabilization is not necessary. You can reboot quickly.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a starting device for an oscillation stabilization wait circuit in one embodiment of the present invention. In Figure 1, 1
2 is a power supply voltage detection circuit, 2 is a flag, 3 is an oscillation stabilization wait circuit, 4 is a power supply voltage, 5.6 is a signal line, and 7 is a reset input terminal.

To explain its operation, first, when turning on the power,
The power supply voltage detection circuit 1 monitors the power supply voltage 4, and when the voltage reaches a level at which all circuit elements can operate, the power supply voltage detection circuit 1 detects that the voltage has reached that voltage and outputs a signal via the signal line 5. and sets flag 2 to “1”. The oscillation stabilization wait circuit 3 can read the state of the flag 2 via the signal line 6. On the other hand, the oscillation stabilization wait circuit 3 can also monitor the reset person cuff. After turning on the power, the reset person's cuff is set to the reset release state. The oscillation stabilization wait circuit 3 is in a state where the reset cuff is released from reset.
The operation starts when flag 2 is "l". At the same time as the counter in the oscillation stabilization wait circuit 3 finishes counting, the oscillation stabilization wait circuit 3 sets the flag 2 via the signal line 6.
After this, the semiconductor device starts normal operation, but if a failure occurs due to some reason and a reset must be applied, the oscillation stabilization wait circuit 3 is cleared because flag 2 is cleared. Even if the reset person cuff is released from reset, the operation does not start and the normal operation can continue.

Since the power supply has already been turned on and the oscillation is stable, there is no problem even if there is no need to wait for the oscillation to stabilize. Second
The figure is a timing diagram sequentially showing an embodiment of the present invention. Flag 2 is set upon recognizing the rise of power supply voltage 4. After that, the reset person cuff is “
The oscillation stabilization wait circuit 3 starts operating because the flag 2 is "1" and the reset is canceled. After that, the normal operation starts, but the reset is canceled. Waiting for oscillation stabilization is not performed even if

In this embodiment, the oscillation stabilization wait operation is started via the flag 2, but the signal from the power supply voltage detection circuit 1 may be directly input to the oscillation stabilization wait circuit 3 to activate it.

Effects of the Invention According to the present invention, by starting the circuit that is waiting for self-oscillation stabilization only when the power is turned on, it is possible to shorten the recovery time from a failure after self-oscillation stabilization, and the system When configured, the recovery time in the event of a failure is an important factor as a measure of how easy system maintenance can be performed, and it is possible to obtain the effect of increasing the system operating rate.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the configuration of a starting device for an oscillation stabilization wait circuit according to an embodiment of the present invention, Fig. 2 is a timing diagram sequentially showing an embodiment of the present invention, and Fig. 3 is a conventional oscillation stabilization wait circuit. FIG. 3 is a timing chart for starting the circuit. 1...Power supply voltage detection circuit, 2...Flag, 3...Oscillation stabilization wait circuit, 4...
Power supply voltage, 5, 6...Signal line, 7...
...Reset input.

Claims (1)

[Claims] A microcomputer with a built-in self-oscillation circuit,
Or a microprocessor with the same circuit built-in,
A starting device for an oscillation stabilization wait circuit, comprising means for starting the self-excited oscillation stabilization wait circuit using a power supply voltage detection circuit and a flag signal only when the power is turned on.