JPH1097340A - Portable information unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To significantly reduce the power consumption of a portable information unit where the power is always supplied to a CPU by controlling the supply of clocks to a CPU. SOLUTION: In regard to a portable information unit where the power is always supplied to a CPU 1, a clock control part 3 starts to transmit a signal to show the stop of supply of clocks to an oscillation circuit 2 when a power switch 4 is turned off. At the same time, the part 3 starts to transmit a signal to reset the CPU 1 in order to reduce the power consumption by keeping the CPU 1 in a static state. When the switch 4 is turned on, the part 3 ends the transmission of a clock stop signal to the circuit 2 and then ends the transmission of a reset signal to the CPU 1 when a prescribed period passed from the end of the transmission of the clock stop signal. Thus, it is possible to prevent such a case where the CPU 1 is operated in an unstable state that is caused right after the circuit 2 started the generation of clocks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable information device in which power from a power supply is constantly supplied to a CPU, and more particularly to a function of controlling a clock supply to the CPU in order to reduce power consumption. The present invention relates to a portable information device.

[0002]

2. Description of the Related Art In recent years, various portable information devices which are easy to carry and can be operated by a battery have been developed. Some portable information devices of this type are designed to restore the contents of the memory to the state immediately before the power switch was turned off when the power switch was turned on (for example, to copy a document that was being created). Restoration, etc.), and a backup system that continuously supplies power regardless of the state of the power switch, and a non-backup system that continuously supplies power only when the power switch is turned on. Some devices have a configuration such as supplying power from a backup power supply.

However, if two power supplies are provided in this manner, the power supply circuit becomes large, so that it is difficult to apply the present invention to information equipment that requires a reduction in the size and cost of the equipment body. There was a problem.

When the power switch is turned off, the contents of the memory are saved in a nonvolatile storage element such as a hard disk drive, and when the power switch is turned on, the nonvolatile storage element is saved. Some operations perform operations such as writing back the data saved in the memory to the memory.

However, since such control is complicated, there is a problem that it is difficult to apply it to information equipment which also requires low cost.
So recently, when the power switch was turned off,
For example, a device such as a display device, which is directly visible to the user, is driven as if the power was turned off, and a CPU or a memory is continuously supplied with power from a power source. Portable information devices that restore the contents of the memory to the state immediately before the power switch was turned off when the power switch was turned on without the need for a system power supply circuit or complicated control have appeared.

[0006]

As described above, some conventional portable information devices require a memory when a power switch is turned on without requiring a plurality of power supply circuits and complicated control. In order to restore the contents to the state immediately before the power switch was turned off, there is an apparatus that always supplies power from a power supply to a CPU, a memory, and the like regardless of the state of the power switch. However, in this type of portable information device, there is a problem that the power that is wasted is increased because the power is continuously supplied to the CPU.

The present invention has been made in view of such circumstances, and in a portable information device of a type in which power from a power supply is always supplied to a CPU, by controlling supply of a clock to the CPU, It is an object of the present invention to provide a portable information device in which power consumption of a CPU is significantly reduced.

[0008]

A first portable information device according to the present invention is a portable information device in which electric power from a power supply is constantly supplied to a CPU, comprising a power switch and the CPU.
An oscillation circuit for generating a clock to be supplied to the CPU, a clock stop signal generating means for generating a clock stop signal for stopping the clock generation of the oscillator circuit, and a reset signal generation for generating a reset signal for resetting the CPU Means, when the power switch is turned off,
First clock control means for causing the clock stop signal generation means to start generating a clock stop signal and causing the reset signal generation means to start generating a reset signal; and Second clock control means for causing the stop signal generation means to stop generating the clock stop signal, and after a predetermined period has elapsed from the end, causing the reset signal generation means to stop generating the reset signal. It is characterized by becoming.

In the first portable information device of the present invention, when the power switch is turned off, the generation of the clock is stopped and the supply of the reset signal to the CPU is started. The CPU is a CMOS (Complete)
entry Metal-Oxide Semico
The CMOS has a feature that the power consumption in a stationary state is extremely small. Therefore, even when the power supply is continuously supplied to the CPU, the generation of the clock supplied to the CPU is stopped when the power switch is turned off, thereby achieving a great reduction in power consumption. It becomes possible. At the same time, it is possible to greatly suggest the power consumption of the oscillation circuit itself.

On the other hand, when the power switch is turned on, the clock generation is started, and the supply of the reset signal is terminated after a lapse of a predetermined period from the start. It takes a certain amount of time from when the oscillation circuit starts generating a clock to when a stable clock is provided. That is, by waiting for the end of the supply of the reset signal for a predetermined period after the start of the clock generation, it is possible to prevent the CPU from operating with the clock in an unstable state and to prevent a malfunction or the like.

It is also effective to start the supply of the reset signal to the CPU not when the power switch is turned off but when the power switch is turned on. That is, if the supply of the reset signal to the CPU is started in synchronization with the start of the clock generation, the malfunction of the CPU due to the unstable clock can be prevented as described above. Further, it is preferable that a period from the start of the clock generation to the end of the supply of the reset signal to the CPU can be set by a register or the like. This is because it is possible to absorb differences in the specifications of the CPU and the like, so that the applicable range can be expanded. Note that this period may be fixedly set or may be set by a utility program or the like.

A second portable information device according to the present invention is a portable information device in which power from a power supply is constantly supplied to a CPU, and includes a power switch and an oscillator for generating a clock supplied to the CPU. Circuit, and the CP of a clock generated by the oscillation circuit in response to an externally input control signal, provided between the CPU and the oscillation circuit.
A logic gate for switching between supply and cutoff to the U, and a control signal for instructing a cutoff of a clock to the logic gate when the power switch is turned off, and the logic when the power switch is turned on. Clock control means for inputting a control signal for instructing clock supply to the gate.

According to the second portable information device of the present invention, when the power switch is turned off, the first portable information device described above is used.
As compared with the portable information device of the invention, the supply of the clock to the CPU is cut off by controlling the logic gate interposed between the oscillation circuit and the CPU instead of stopping the generation of the clock. In this case as well, the CPU can be brought into a stationary state as described above, so that the power consumption can be significantly reduced. On the other hand, since the clock generation is continued, when the clock supply to the CPU is started by controlling the logic gate (when the power switch is turned on), the stable clock is supplied immediately. Will be done. Therefore, if it is possible to set whether to reset the CPU when the power switch is turned on by using a register or the like, depending on the setting, the processing that was being executed when the power switch was turned off may be continued. Is further possible.

A third portable information device according to the present invention is a portable information device in which power from a power supply is constantly supplied to a CPU, and includes a power switch and an oscillator for generating a clock supplied to the CPU. A clock stop signal generating means for generating a clock stop signal for stopping clock generation of the oscillator circuit; and a clock stop signal generating means interposed between the CPU and the oscillator circuit for responding to an externally input control signal. The CPU of the clock generated by the oscillation circuit
A logic gate for switching supply / interruption to the power supply, and, when the power switch is turned off, causing the clock stop signal generating means to start generating a clock stop signal.
First clock control means for inputting a control signal for instructing a cutoff of a clock to the logic gate; and when the power switch is turned on, the clock stop signal generation means causes the clock stop signal generation means to stop generating a clock stop signal. And a second clock control means for inputting a control signal for instructing the logic gate to supply a clock after a predetermined period has elapsed from the end.

In the third portable information device of the present invention, when the power switch is turned off, the generation of the clock is stopped and the supply of the clock to the CPU is cut off by the oscillation circuit and the CPU. To control the logic gate intervening between them. On the other hand, when the power switch is turned on, the clock generation is started, and after a lapse of a predetermined period from the start, the supply of the clock to the CPU is started by controlling the logic gate. That is,
Only a stable clock is supplied to the CPU, and the power consumption is much larger than that of the portable information device of the second invention because the clock generation of the oscillation circuit is stopped when the power switch is off. , And the processing that was being performed when the power switch was turned off can be continued.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) First, a first embodiment of the present invention will be described. FIG. 1 shows a part of a schematic configuration of a portable information device according to the present embodiment.

The CPU 1 mounted on the portable information device of the present embodiment is always supplied with power from a power source irrespective of the state (on / off) of the power switch 4 and the clock generated by the oscillation circuit 2 It operates by receiving the supply of. Further, after the reset signal is transmitted from the clock control unit 3, the CPU 1 executes a reset process for initializing an internal state or the like when the transmission is completed. The oscillation circuit 2 generates a clock for operating the CPU 1, but when a control signal (clock stop signal) instructing to stop the clock generation is input from the clock control unit 3, the generation of the clock is stopped. It is configured to be. Further, the clock control unit 3 transmits a control signal to the CPU 1 and the oscillation circuit 2 as described below in response to the operation of the power switch 4. (1) When the power switch is turned off The transmission of the clock stop signal to the oscillation circuit 2 is started, and the transmission of the reset signal to the CPU 1 is started. (2) When the power switch is turned on The transmission of the clock stop signal to the oscillation circuit 2 ends,
After a predetermined period has elapsed from the end, the CP
The transmission of the reset signal to U1 ends.

Similarly to the CPU 1, the memory 5 is always supplied with power from a power supply, and keeps holding various data such as a document being created even while the power switch 4 is off.

FIG. 2 shows the relationship between the power switch (a), the clock (b) and the reset signal (c) of the present embodiment. As shown in FIG. 2, when the power switch 4 is turned off ((1) in FIG. 2), the clock control unit 3 starts transmitting a clock stop signal to the oscillation circuit 2, thereby stopping the generation of the clock. I do. C
Since the PU1 is made of CMOS, the power consumption in the stationary state where no clock is supplied is very small. Therefore, even when the power is constantly supplied to the CPU 1, the power consumption while the power switch 4 is off can be significantly reduced. At this time, the clock control unit 3 also starts transmitting a reset signal to the CPU 1.

On the other hand, when the power switch 4 is turned on ((2) in FIG. 2), the clock control unit 3 terminates the transmission of the clock stop signal to the oscillation circuit 2 so that
Clock generation is resumed. After that, when a predetermined period has elapsed ((3) in FIG. 2), the clock control unit 3 terminates the transmission of the reset signal to the CPU 1, so that the CPU 1 initializes the internal state and the like. Start execution of the process. For a while after the oscillation circuit 2 starts generating the clock, an unstable clock is generated and output. Therefore, in the portable information device of the present embodiment, the clock control unit 3 causes the CPU 1 to operate with the clock in an unstable state by making the supply of the reset signal wait for a predetermined period after the start of the clock generation. To prevent that. The period during which the supply of the reset signal is waited is set, for example, by a register or the like provided in the clock control unit 3 (or can be referred to). Therefore, CPU
An appropriate working environment can always be obtained in accordance with the type of the oscillator 1 and the oscillation circuit 2 and the installation state thereof.

By controlling the generation of the clock to be supplied to the CPU, the power from the power
In a portable information device of the type supplied to U,
It is realized that the power that U wastes wastefully is significantly reduced.

Note that the same effect can be obtained even when the transmission start timing of the reset signal is set when the power switch is turned on. FIG. 3 shows the relationship among the power switch (a), clock (b) and reset signal (c) at this time.

That is, when the power switch 4 is turned on ((1) in FIG. 3), the clock control unit 3
The clock generation is resumed by ending the transmission of the clock stop signal to
The clock control unit 3 also starts transmitting a reset signal to the CPU 1. After that, when the clock control unit 3 elapses a predetermined period ((2) in FIG. 3), the CPU 1 terminates the transmission of the reset signal to the CPU 1, thereby initializing the internal state and the like. Start execution of the process.

As a result, the CPU 1 does not start processing until the clock generated by the oscillation circuit 2 is stabilized, so that it is possible to prevent malfunction due to operation with an unstable clock as described above. .

(Second Embodiment) Next, a second embodiment of the present invention will be described. FIG. 4 shows a part of a schematic configuration of the portable information device according to the present embodiment.

The portable information device of the present embodiment differs from the portable information device of the first embodiment shown in FIG.
The difference is that a logic gate 6 is interposed between the CPU 1 and the oscillation circuit 2. In the portable information device of the first embodiment, a control signal line is laid between the clock control unit 3 and the oscillation circuit 2. However, in the portable information device of the present embodiment, a clock control is performed instead. A control signal line is laid between the unit 3 and the logic gate 6.

That is, the oscillation circuit 2 according to the present embodiment
The clock for operating the PU 1 is constantly generated, and the logic gate 6 supplies / cuts off the clock generated by the oscillation circuit 2 to the CPU 1 in response to the control signal input from the clock control unit 3. Switch. Therefore, the clock control unit 3 of the present embodiment includes the power switch 4
In response to the above operation, a control signal is transmitted to the CPU 1 and the logic gate 6 as described below. (1) When the power switch is turned off A control signal for instructing a cutoff of a clock is transmitted to the logic gate 6 and a transmission of a reset signal to the CPU 1 is started. (2) When the power switch is turned on: A control signal for instructing the supply of the clock to the logic gate 6 is transmitted, and the transmission of the reset signal to the CPU 1 is terminated.

As a result, as in the first embodiment, the supply of the clock to the CPU 1 can be cut off while the power switch 4 is turned off, and the power consumed by the CPU 1 wastefully can be greatly reduced. Becomes possible.

It should be noted that the oscillation circuit 2 of the present embodiment has a CPU
1 always operates, so that a stable clock is immediately supplied to the CPU 1 when a control signal indicating clock supply is transmitted from the clock controller 3 to the logic gate 6. Will be done. That is, unlike the first embodiment, there is no need to consider waiting for the clock to stabilize. Therefore, for example, when the power switch 4 is operated, the CPU
If the clock control unit 3 can set whether or not to reset 1 by using a register or the like provided in the clock control unit 3, not only the data stored in the memory 5 is retained, but also the operation is interrupted by turning off the power switch 4. Processing (execution of a program) can be continuously executed.

(Third Embodiment) Next, a third embodiment of the present invention will be described. FIG. 5 shows a part of a schematic configuration of the portable information device according to the present embodiment.

The portable information device of the present embodiment differs from the portable information device of the first embodiment shown in FIG. 1 in that the logic gate 6 () of the portable information device of the second embodiment shown in FIG. And a control signal line between the logic gate 6 and the clock control unit 3). Then, in the portable information device of the present embodiment, the clock control unit 3 transmits a control signal to the oscillation circuit 2 and the logic gate 6 as described below in response to the operation of the power switch 4. (1) When the power switch is turned off The transmission of the clock stop signal to the oscillation circuit 2 is started, and the control signal for instructing the logic gate 6 to cut off the clock is transmitted. (2) When the power switch is turned on The transmission of the clock stop signal to the oscillation circuit 2 ends,
After a predetermined period has elapsed from the end, a control signal for instructing the supply of a clock is transmitted to the logic gate 6.

FIG. 6 shows the relationship among the power switch (a), the clock (b) and the logic gate control signal (c) of the present embodiment. As shown in FIG. 6, when the power switch 4 is turned off ((1) in FIG. 6), the clock control unit 3 starts transmitting a clock stop signal to the oscillation circuit 2, thereby stopping clock generation. I do. Thereby, the power consumption of both the CPU 1 and the oscillation circuit 2 while the power switch 4 is off is greatly reduced. Then, at this time, the clock control unit 3 transmits a control signal indicating cutoff of the clock to the logic gate 6.

On the other hand, when the power switch 4 is turned on ((2) in FIG. 6), the clock control unit 3 terminates the transmission of the clock stop signal to the oscillation circuit 2 so that
Clock generation is resumed. After that, when a predetermined period has elapsed ((3) in FIG. 6), the clock control unit 3 transmits a control signal indicating supply of a clock to the logic gate 6.

That is, the portable information device according to the present embodiment stops the clock generation of the oscillation circuit 2 when the power switch 4 is turned off compared to the portable information device according to the second embodiment. In addition to realizing a reduction in power consumption, only a stable clock is supplied to the CPU 1, so that a process (execution of a program) interrupted by turning off the power switch 4 can be continuously executed.

In this embodiment, resetting the CPU 1 in response to the operation of the power switch 4 is effective. As shown in the second embodiment, when the power switch 4 is operated, the CPU 1 is reset. The clock control unit 3 is provided with (or can refer to) whether to reset
What is necessary is just to be able to set by a register etc.

[0036]

As described above in detail, according to the present invention, in a portable information device of a type in which power from a power supply is always supplied to a CPU, a CMOS having a very small power consumption in a stationary state is used. Using the features, the supply of the clock to the CPU is controlled as follows.

(1) When the power switch is turned off,
Stop the clock generation of the oscillation circuit and
Transmission of a reset signal to the oscillator circuit is started. On the other hand, when the power switch is turned on, clock generation of the oscillator circuit is started, and after the start, a clock is generated for a predetermined period (when the clock generated by the oscillator circuit becomes stable). After the elapse of a sufficient period, the transmission of the reset signal to the CPU ends.

[0038] Thereby, the power that the CPU and the transmission circuit wastefully consume while the power switch is turned off is greatly reduced, and it is possible to prevent the CPU from operating with an unstable clock to cause a malfunction or the like. To prevent

(2) When the power switch is turned off,
The supply of the clock generated by the oscillation circuit to the CPU is interrupted, and the supply of the clock generated by the oscillation circuit to the CPU is restarted when the power switch is turned on.

In this case, the power wasted by the CPU while the power switch is turned off is greatly reduced, and the oscillation circuit keeps generating the clock at all times. The supplied clock is supplied to the CPU, and the interrupted processing can be continuously executed.

(3) When the power switch is turned off,
While stopping the clock generation of the oscillation circuit, the supply path of the clock generated by the oscillation circuit to the CPU is cut off,
On the other hand, when the power switch is turned on, the clock generation of the oscillation circuit is started, and after a predetermined period (a period sufficient for the clock generated by the oscillation circuit to be stabilized) elapses after the start, Then, the cutoff of the supply path of the clock generated by the oscillation circuit to the CPU ends.

As a result, wasteful power consumption by both the CPU and the transmission circuit while the power switch is turned off is greatly reduced, and only a stable clock is supplied to the CPU. , And the continued execution of the interrupted processing is also possible.

[Brief description of the drawings]

FIG. 1 is an exemplary view showing a part of a schematic configuration of a portable information device according to a first embodiment of the present invention.

FIG. 2 is an exemplary view showing a relationship among a power switch (a), a clock (b), and a reset signal (c) according to the embodiment;

FIG. 3 is an exemplary view showing a relationship among a power switch (a), a clock (b), and a reset signal (c) according to the embodiment;

FIG. 4 is an exemplary view showing a part of a schematic configuration of a portable information device according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a part of a schematic configuration of a portable information device according to a third embodiment of the present invention.

FIG. 6 is an exemplary view showing the relationship among a power switch (a), a clock (b), and a logic gate control signal (c) of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... CPU 2 ... Oscillation circuit 3 ... Clock control part 4 ... Power switch 5 ... Memory 6 ... Logic gate

Claims (12)

[Claims] 1. A portable information device in which power from a power supply is constantly supplied to a CPU, a power switch, an oscillation circuit for generating a clock to be supplied to the CPU, and stopping the clock generation of the oscillation circuit. A clock stop signal generating means for generating a clock stop signal for resetting the CPU, a reset signal generating means for generating a reset signal for resetting the CPU, and the clock stop signal generating means when the power switch is turned off. First clock control means for starting generation of a clock stop signal and causing the reset signal generation means to start generation of a reset signal; and when the power switch is turned on, the clock stop signal generation means stops the clock. End the signal generation,
A portable information device comprising: a second clock control means for terminating the generation of a reset signal in the reset signal generation means after a predetermined period has elapsed from the end thereof. 2. A portable information device in which power from a power supply is constantly supplied to a CPU, a power switch, an oscillation circuit for generating a clock to be supplied to the CPU, and stopping generation of a clock of the oscillation circuit. A clock stop signal generating means for generating a clock stop signal for resetting the CPU, a reset signal generating means for generating a reset signal for resetting the CPU, and the clock stop signal generating means when the power switch is turned off. First clock control means for starting the generation of a clock stop signal, and when the power switch is turned on, causing the reset signal generation means to start generating a reset signal and causing the clock stop signal generation means to stop the clock. The generation of the signal is terminated, and after a lapse of a predetermined period from the termination, the resetting is performed. Portable information equipment comprising: a second signal control means for terminating the generation of the reset signal in the first signal generation means. 3. A register for storing data designating a period from a time when the clock stop signal generating means completes generation of the clock stop signal to a time when the reset signal generating means terminates generation of the reset signal is provided. The second clock control means causes the reset signal generation means to terminate the generation of the reset signal after a period specified by the data stored in the register has elapsed since the generation of the clock stop signal was terminated. 3. The portable information device according to claim 1, wherein: 4. A portable information device in which electric power from a power supply is constantly supplied to a CPU, comprising: a power switch; an oscillation circuit for generating a clock to be supplied to the CPU; A logic gate that is provided interposed and switches between supply and cutoff of a clock generated by the oscillation circuit to the CPU in response to a control signal input from the outside; and a logic gate when the power switch is turned off. And a clock control means for inputting a control signal for instructing the logic gate to supply a clock to the logic gate when the power switch is turned on. Portable information equipment. 5. A portable information device in which power from a power supply is always supplied to a CPU, comprising: a power switch; an oscillation circuit for generating a clock to be supplied to the CPU; A logic gate that is provided interposed therebetween and switches supply / cutoff of a clock generated by the oscillation circuit to the CPU in response to a control signal input externally; and a reset that generates a reset signal for resetting the CPU. A first clock control for inputting a control signal for instructing a cutoff of a clock to the logic gate when the power switch is turned off, and causing the reset signal generation means to start generating a reset signal; Means for inputting a control signal for instructing a supply of a clock to the logic gate when the power switch is turned on. And a second clock control means for terminating the generation of the reset signal in the reset signal generation means. 6. A portable information device in which power from a power supply is constantly supplied to a CPU, comprising: a power switch; an oscillation circuit for generating a clock to be supplied to the CPU; A logic gate that is provided interposed therebetween and switches supply / cutoff of a clock generated by the oscillation circuit to the CPU in response to a control signal input externally; and a reset that generates a reset signal for resetting the CPU. Signal generating means; first clock control means for inputting a control signal for instructing a cutoff of a clock to the logic gate when the power switch is turned off; and resetting when the power switch is turned on. A signal generation means starts generation of a reset signal, and a control signal for instructing supply of a clock is input to the logic gate. Portable information equipment comprising: a second clock control means for causing the reset signal generation means to terminate the generation of the reset signal after the input. 7. A register for storing data for specifying whether or not to reset the CPU when the power switch is operated, wherein the second clock control means stores the C in the register.
7. The portable information device according to claim 5, wherein the drive of the reset signal generating means is controlled only when data for resetting the PU is stored. 8. A portable information device in which power from a power supply is constantly supplied to a CPU, a power switch, an oscillation circuit for generating a clock to be supplied to the CPU, and stopping generation of a clock of the oscillation circuit. And a clock stop signal generating means for generating a clock stop signal for providing a clock stop signal for generating a clock stop signal for the clock generated by the oscillator circuit in response to an externally input control signal A logic gate for switching supply / interruption to a power supply, and a control signal for instructing the logic gate to shut off a clock while causing the clock stop signal generating means to start generating a clock stop signal when the power switch is turned off. A first clock control means for inputting a clock signal to the clock stop signal generating means when the power switch is turned on. Stop the generation of the lock stop signal,
A portable information device comprising: a second clock control unit that inputs a control signal for instructing a clock to be supplied to the logic gate after a predetermined period has elapsed from the end thereof. 9. A reset signal generating means for generating a reset signal for resetting the CPU, and a register for storing data for specifying whether to reset the CPU when the power switch is operated. Said second clock control means stores said C in said register.
When the data for resetting the PU is stored, before inputting a control signal instructing the supply of a clock to the logic gate, the reset signal generation means starts generating a reset signal, and 9. The portable information device according to claim 8, further comprising means for terminating generation of a reset signal to said reset signal generation means after inputting a control signal instructing supply of the information. 10. A portable information device in which power from a power supply is constantly supplied to a CPU, comprising: an oscillation circuit for generating a clock to be supplied to the CPU; and a clock stop for stopping clock generation of the oscillation circuit. A clock stop signal generating means for generating a signal; a reset signal generating means for generating a reset signal for resetting the CPU; and a clock stop signal generating means for generating a clock stop signal when a system stop request is generated. And first clock control means for causing the reset signal generation means to start generating a reset signal, and causing the clock stop signal generation means to end generation of a clock stop signal when a system start request is generated. After a predetermined period elapses from the end, the reset signal generating means is reset. Second mobile information device characterized by comprising comprises a clock control means for terminating the generation of Tsu bets signals. 11. A portable information device in which electric power from a power supply is constantly supplied to a CPU, comprising: an oscillation circuit for generating a clock to be supplied to the CPU; and an intervening circuit provided between the CPU and the oscillation circuit. A logic gate for switching supply / interruption of the clock generated by the oscillation circuit to the CPU in response to a control signal input from the outside; and a logic gate for shutting down the clock when a system stop request occurs. A portable information device comprising: clock control means for inputting a control signal to instruct the logic gate and inputting a control signal to supply a clock to the logic gate when a system start request is generated. . 12. A portable information device in which power from a power supply is constantly supplied to a CPU, comprising: an oscillation circuit for generating a clock to be supplied to the CPU; and a clock stop for stopping clock generation of the oscillation circuit. A clock stop signal generating means for generating a signal, provided between the CPU and the oscillating circuit, for supplying a clock generated by the oscillating circuit to the CPU in response to an externally input control signal; A first logic gate for switching off, and a control signal for instructing the logic gate to shut off the clock while causing the clock stop signal generation means to start generating a clock stop signal when a system stop request is generated. Generating a clock stop signal to said clock stop signal generating means when a system start request is generated. And a second clock control means for inputting a control signal for instructing the logic gate to supply a clock after a predetermined period has elapsed from the end. Information equipment.