JPH11212680A - Start-up control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption of a CPU and to immediately perform reaction to a power-on request as well. SOLUTION: Power from a power source terminal 1 is supplied to an edge detection circuit 21 and a clock circuit 22 of a microcomputer 2, and is also supplied through a switch 23 to a CPU 24. Besides, the power source terminal 1 is grounded through a series circuit of a resistor 3 and a power source switch 5 and the midpoint of this connection is connected to the edge detection circuit 21. Further, an oscillator 5 is connected to the clock circuit 22, while trigger signals from these edge detection circuit 21 and lock circuit 22 are supplied to the CPU 24. Concerning this CPU 24, when the switch 23 is turned off, a main power source is turned off and a stop (sleep) state is provided. When the trigger signals from the edge detection circuit 21 or clock circuit 22 are supplied, the switch 23 is turned on and a control signal is supplied to a power source block 69, or after clock processing is performed, the switch 23 is turned off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a startup control method suitable for use in, for example, a microcomputer for controlling a recording / reproducing apparatus integrated with a camera.

[0002]

2. Description of the Related Art For example, a recording / reproducing apparatus integrated with a camera has a built-in clock circuit or the like so that a date and a current time can always be displayed. In such a device, for example, a clock circuit is continuously driven, and a CPU (Central Processing Unit) for processing a signal from the clock circuit also needs to be constantly driven, which consumes much power. It will be.

In other words, such power consumption occurs even when, for example, the entire recording / reproducing apparatus integrated with a camera is not driven. Therefore, if this is not noticed, for example, when the entire device needs to be driven, there is a possibility that the device becomes unusable due to consumption of a built-in battery.

On the other hand, there is a method of minimizing power consumption, for example, while a clock circuit is driven continuously, but a CPU or the like is driven only when a signal at a predetermined interval is supplied from the clock circuit. It is considered. However, in this method, the CPU or the like is driven only when a signal at a predetermined interval is supplied from the above-described clock circuit. Therefore, for example, even when there is a request to turn on the main power, the CPU determines only at the above-described interval. Therefore, the response to the input request may be delayed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of such a point, and the problem to be solved is that the conventional method uses a CPU (central processing unit) for processing a signal from a clock circuit. This increases the power consumption of the processing device, etc., and may delay the response to the input request.

[0006]

For this reason, in the present invention, a CPU (Central Processing Unit) is activated by a trigger signal, and the trigger signal is discriminated, and the CPU process is performed according to the discrimination. According to this, the power consumption of the CPU can be reduced, and the response to the request for turning on the main power can be performed immediately.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a central processing unit is started by a trigger signal at a predetermined interval from a clock circuit driven by a continuous power supply in a state where a main power supply is cut off, and the trigger signal is generated by the central processing unit. When the trigger signal is determined to be from a clock circuit, the central processing unit processes the signal from the clock circuit and then stops the operation of the central processing unit.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an example of a microcomputer for controlling a recording / reproducing apparatus integrated with a camera, for example, to which the activation control method according to the present invention is applied.

In FIG. 1, for example, a main power supply (not shown)
A power supply terminal 1 to which power is supplied from is connected to a microcomputer (microcomputer) 2. In the microcomputer 2, power from the power supply terminal 1 is supplied to an edge detection circuit 21 and a clock circuit 22, and also to a central processing unit (CPU) 24 through a switch 23 described later.

A power terminal 1 is grounded through a series circuit of a resistor 3 and a power switch 4. The midpoint of connection between the resistor 3 and the power switch 4 is connected to the edge detection circuit 21 of the microcomputer 2. As a result, when the power switch 4 is turned on, the edge detection circuit 21
The falling edge is detected, and a trigger signal for a power-on request is formed.

A vibrator 5 serving as a reference of a clock is connected to a clock circuit 22 of the microcomputer 2. Thus, in the clock circuit 22, for example, 3
The reference signal of 2 kHz is counted, and a trigger signal for a predetermined clock process is formed, for example, every second. Then, trigger signals from the edge detection circuit 21 and the clock circuit 22 are supplied to the CPU 24.

Further, in the CPU 24, when the switch 23 is turned off, the main power supply is shut off and the CPU 24 is stopped (sleep). And the above-described edge detection circuit 2
When the trigger signal is supplied from the clock signal 22 and the clock circuit 22, only the process related to the activation (wake-up) described later is executed by the power of the trigger signal.

The on / off of the switch 23 is controlled by a control signal generated by the CPU 24 and the CPU of the microcomputer 2
The control signal formed at 24 is supplied to, for example, a power supply block 6 that controls the power supply of the entire apparatus.

That is, in the flowchart shown in FIG. 2, for example, when a power-off process (step [1]) is performed at an arbitrary time from a normal operation state (not shown), the CPU 24 enters a sleep state in step [2]. (Switch 2
3 is turned off). When there is a wake-up request (supply of a trigger signal) from the edge detection circuit 21 or the clock circuit 22 in this sleep state, the CPU 24 is started (step [2b]) from the sleep state (step [2a]).

In step [3], it is determined whether or not the wake-up request is a power-on request from the edge detection circuit 21. If it is not a request to turn on the power (N), it is determined that a request for clock processing from the clock circuit 22 is made, and the clock count processing (the processing by the CPU 24 by turning on the switch 23) is performed in step [4]. Will be When this process ends, the process returns to the step [2] and returns to C.
The PU 24 is put into the sleep state (the switch 23 is turned off).

If the wake-up request is a power-on request from the edge detection circuit 21 in step [3] (Y), power-on processing (switch 23 is turned on and CPU 24 executes processing in step [5]) ) Is performed.
In this process, a control signal from the CPU 24 is supplied to the power supply block 6, for example, the power supply of the entire apparatus is started, and the entire apparatus is put into, for example, a normal operation state.

FIG. 3 is a timing chart. For example, in a steady state where the power supply is off, as shown in FIG. The determination of the power-on request and the clock counting process are performed, and the process returns to the sleep state. As a result, the time during which the CPU 24 is driven is shortened to reduce power consumption.

When the power switch 4 is turned on, as shown in FIG. 3B, the signal from the power switch 4 falls, so that the CPU 24 is started. Can proceed. As a result, it is possible to immediately respond to the power-on request.

Therefore, in this activation control method, the CPU (Central Processing Unit) is activated by a trigger signal, and the trigger signal is discriminated and the CPU process is performed according to the discrimination, thereby reducing the power consumption of the CPU. In addition to this, it is possible to immediately respond to a request to turn on the main power supply.

As a result, in the conventional method, the power consumption of a CPU (Central Processing Unit) for processing a signal from a clock circuit and the like may be increased, and the response to an input request may be delayed. According to the present invention, these problems can be easily solved.

That is, in this method, for example, the consumption of the built-in battery when the whole recording / reproducing apparatus integrated with the camera is not driven is reduced, and the built-in battery is used when the whole apparatus needs to be driven. It is possible to reduce the risk of becoming unusable due to exhaustion of the device and to immediately start driving the entire device.

According to the above-described start control method, the central processing unit is started by the trigger signal at a predetermined interval from the clock circuit driven by the continuous power supply in a state where the main power supply is cut off, and the trigger signal is generated by the central processing unit. When the trigger signal is determined to be from the clock circuit, the central processing unit processes the signal from the clock circuit and then stops the operation of the central processing unit, thereby reducing the power consumption of the central processing unit. And can immediately respond to a request to turn on the main power supply.

[0023]

According to the first aspect of the present invention, the CPU (Central Processing Unit) is activated by a trigger signal, the trigger signal is discriminated, and the CPU process is performed according to the discrimination. Power consumption can be reduced, and a response to a request to turn on the main power supply can be made immediately.

As a result, in the conventional method, the power consumption of a CPU (Central Processing Unit) or the like that processes signals from the clock circuit increases, and the response to the input request may be delayed. According to the present invention, these problems can be easily solved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an example of a microcomputer to which the present invention is applied.

FIG. 2 is a flowchart for explaining the operation.

FIG. 3 is a diagram for explaining this.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Power supply terminal, 2 ... Microcomputer, 21 ... Edge detection circuit, 22 ... Clock circuit, 23 ... Switch, 24 ...
Central processing unit (CPU), 3 ... resistor, 4 ... power switch, 5 ... vibrator, 6 ... power block

Claims (2)

[Claims] 1. A central processing unit is started by a trigger signal at a predetermined interval from a clock circuit driven by a continuous power supply in a state where a main power supply is cut off, and the central processing unit determines the trigger signal. When the signal is determined to be from the clock circuit, the central processing unit processes the signal from the clock circuit and then stops the operation of the central processing unit. 2. The activation control method according to claim 1, further comprising: activating said central processing unit by a trigger signal from said main power-on request means driven by said continuous power supply; A start control method characterized in that a signal is determined, and when the trigger signal is determined to be from the input requesting means, the processing of turning on the main power is started in the central processing unit.