JP2003271411A - Electronic equipment provided with control circuit having program runaway detection function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electronic equipment unnecessitating a restoring operation to restore the operation of the equipment to an operation before a runaway of a program, capable of executing an original control processing without delay during the operation of the equipment and enabling a simple constitution of a microcomputer. <P>SOLUTION: In this electronic equipment, the microcomputer 2 is connected to control object blocks 3 to 6 to be controlled. The microcomputer 2 is provided with a watch dog timer 23, an information register 24 and a CPU 20. The CPU 20 executes writing of operation information showing an operation state of the equipment in the information register 24 when the operation state is changed. The CPU 20 restores the operations of the control object blocks 3 to 6 to the operations before the runaway of the program based on all or partial operation information written in the information register 24 when an interruption signal is received from the watch dog timer 23 due to runaway of the program. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device whose operation is controlled by a control circuit having a program runaway detection function.

[0002]

2. Description of the Related Art Conventionally, there is known a microcomputer capable of detecting runaway of a program by including a watchdog timer (Japanese Patent No. 28700).
No. 83 [G06F 11/30]). In this type of microcomputer, when the program is normally executed, a clear signal is supplied from the CPU to the watchdog timer at a constant cycle, and the watchdog timer receives the clear signal and sets the time measurement value to zero. Initialize to. On the other hand, if the program runs out of control and the CPU does not normally supply the clear signal to the watchdog timer, the watchdog timer time measurement value exceeds the predetermined threshold, and the watchdog timer An abnormality detection signal is supplied from the timer to the CPU. When the abnormality detection signal is input to the CPU in this manner, a predetermined interrupt processing routine is executed and the CPU and other hardware constituting the microcomputer are reset.

[0003]

By the way, it is conceivable to configure an electronic device such as an audio device by using the microcomputer having a watchdog timer. However, in an electronic device including the above microcomputer, when a program runaway is detected, the CPU and other hardware constituting the microcomputer are reset to the initial state and the state of the device is restored to the initial state. However, there is a problem that the user must thereafter perform a recovery operation for recovering the operation of the device to the operation before the program runaway. For example, in an audio device having a CD playback function, if a program goes out of control while playing a CD, the state of the device is reset to a stopped state immediately after power-on,
The user has to perform an operation for starting the reproduction of the CD from the reproduction position at the time of the program runaway.

Therefore, when a program runaway is detected, a microcomputer capable of restoring the operation of the CPU to the operation before the program runaway has been proposed (Japanese Patent Laid-Open No. 9-190360 [G06F 11]. / 00]). In this type of microcomputer, the values of the program counter and multiple registers are saved in the save memory, and when a program runaway is detected, the values of the program counter and multiple registers are saved in the save memory. Are replaced by a plurality of values, and the operation of the CPU is restored to the operation before the runaway of the program. Therefore, when the electronic device is configured by using the microcomputer, the operation of the device is automatically restored to the operation before the program runaway, and the recovery operation by the user becomes unnecessary.

However, in an electronic device equipped with the above microcomputer, the saving process is performed for a large number of values between the program counter or a plurality of registers and the saving memory during the operation of the device. There is a problem that the original control processing for controlling the operation of is delayed. In addition, the microcomputer must be equipped with a save memory and a save / restore control circuit that executes save and replace operations between the save memory and the program counter and a plurality of registers. There are complex issues. Further, since the save memory must store a large number of values of the program counter and a plurality of registers, it is required to have a large recording capacity, and the save / restore control circuit saves a large number of values. In order to perform the operation and the replacement operation, it is required to have a high processing speed. Therefore, there is a problem that the cost required for the microcomputer is higher than that of the conventional one. The object of the present invention is to eliminate the need for a recovery operation for recovering the operation of the device to the operation before the program runaway, and still to be able to execute the original control processing without delay during the operation of the device. It is another object of the present invention to provide an electronic device that has a simple control circuit configuration and can suppress an increase in cost required for the control circuit.

[0006]

By the way, in a conventional audio device, a microcomputer stores operation information representing an operation state of the device. For example, CD
In the case of an audio device having a playback function of a CD and a tuner function of a radio broadcast, a playback source is a CD as operation information.
Alternatively, information indicating which of the radio broadcasts is being received, the receiving frequency of the tuner, the address indicating the reproduction position of the CD, and the like are held. Therefore, as a result of earnest research to solve the above problems, the present inventors have come to the idea of using the above operation information for restoration processing of the operation of the device, and have completed the present invention.

In the electronic device according to the present invention, the control circuit having the program runaway detection function controls the operation of the device and stores one or a plurality of operation information indicating the operating state of the device. Then, the control circuit includes recovery means for recovering the operation of the device to the operation before the program runs out of control based on all or part of the stored operation information when the program runaway is detected. .

In the electronic equipment, the control circuit periodically or irregularly stores the operation information indicating the operation state of the equipment, and when the program runaway is detected, the operation information immediately before the program runaway is detected. Is remembered. Therefore, when a program runaway is detected,
By using all or part of the operation information stored at that time, the operation of the device can be restored to the operation before the program runs away. In this way, when a program runaway is detected, the operation of the device is automatically restored to the operation before the program runaway, and thus the user's recovery operation is unnecessary. Further, in order to restore the operation of the device, since all or part of the operation information stored by the microcomputer in the conventional electronic device is used, the operation of the device is restored to the operation before the program runaway. No new process for storing information other than information is required. Therefore, the original control process can be executed without delay during the operation of the device. Further, since the save memory and save / restore control circuit described above are not required, the configuration of the control circuit is simple and the increase in cost required for the control circuit can be suppressed.

More specifically, the control circuit is provided with operation information storage means for storing operation information, and write permission / prohibition information in which write permission / prohibition information indicating permission / prohibition of writing information to the operation information storage means is stored. Based on the storage means and the write permission / prohibition information, it is determined whether or not writing of information to the movement information storage means is permitted, and the movement information is stored in the movement information storage means only when it is determined that writing is permitted. And means for writing information.

If a configuration is adopted in which writing to the operation information storage means is always possible when a write request to the operation information storage means occurs, from the time when the program runaway occurs until the recovery processing is started. If a write request is issued to the operation information storage means in the meantime, the operation information stored in the operation information storage means may be rewritten. In this case, the operation of the device cannot be restored to the operation before the program runaway. . Therefore, in the above specific configuration, the write permission / prohibition information is stored in the write permission / prohibition information storage means, and the motion information is stored in the motion information storage means only when the write permission / refusal information represents the permission of writing to the motion information storage means. Written. In such a configuration, when the program is normally executed, a write request of the operation information to the operation information storage means is made when the write approval / disapproval information indicates that the operation is allowed to be stored. Will be written to the means. On the other hand, if a write request is issued to the operation information storage means while the program is running out of control, it is highly likely that the write permission / prohibition information indicates that writing is prohibited. Therefore, even if a write request is issued to the operation information storage unit between the time when the program has runaway and the restoration process is started, the operation information written in the operation information storage unit is The possibility of rewriting is extremely low, and it is possible to prevent a situation in which the operation of the device cannot be restored to the operation before the program runaway because the operation information is rewritten.

More specifically, when the program runaway is detected, the recovery means of the control circuit restores the operation of the device to the operation before the program goes out of control, while turning on the power of the device body. When the reset operation is performed or the reset operation is performed, the state of the device is set to the initial state.

In the above specific configuration, when the program runaway is detected, the operation of the device is restored to the operation before the program runaway. On the other hand, when the user turns on the power of the device body or when the user performs a reset operation, the state of the device is set to an initial state, for example, a state where the operation of the device is stopped.

More specifically, the control circuit takes one of a first value indicating that a program runaway has been detected and a second value indicating that a program runaway has not been detected, and a runaway detection. It has a flag storage means for the presence / absence flag, and a recovery command means for outputting a recovery operation start command to the recovery means when the power of the device body is turned on or when a reset operation is performed. The recovery means receives the recovery operation start command and determines whether the runaway detection presence / absence flag has a first value or a second value, and the runaway detection presence / absence flag. Is determined to take the first value, the operation of the device is restored to the operation before the program goes out of control, and the runaway presence / absence flag is rewritten to the second value. When it is determined that it takes the second value, a recovery processing unit that sets the state of the device to the initial state, and when a program runaway is detected, the runaway detection presence / absence flag is rewritten to the first value. At the same time, an interrupt processing means for outputting a restoration operation start command to the judging means is provided.

In the above specific configuration, when the user turns on the power of the device main body or when the user performs a reset operation, the restoration command means outputs a restoration operation start command to the restoration means. The determination means of the recovery means receives the recovery operation start command and determines whether the runaway detection presence / absence flag has the first value or the second value. At this time, it is determined that the runaway detection presence / absence flag has the second value, and the recovery processing means sets the state of the device to the initial state. On the other hand, when the program runaway is detected, the interrupt processing means rewrites the runaway detection presence / absence flag to the first value, and
A recovery operation start command is output from the interrupt processing means to the determination means, and the determination means receives the recovery operation start command,
It is determined whether the runaway detection presence / absence flag has a first value or a second value. At this time, it is determined that the runaway detection presence / absence flag has the first value, and the recovery processing unit restores the operation of the device to the operation before the program runs out of control, and sets the runaway detection presence / absence flag to the second value. Overwrite with a value.

Furthermore, more specifically, the control circuit measures the passage of time, resets the measured value to an initial value when receiving a reset command, and when the measured value exceeds a predetermined threshold value. A watchdog timer that outputs a runaway detection signal to the recovery means, and a reset command to the watchdog timer at a cycle shorter than the time from when the measured value exceeds a predetermined threshold to the predetermined value. And a reset command means for resetting.

In the above specific configuration, when the program is normally executed, the reset command means instructs the watchdog timer to wait longer than the time from when the measured value of the timer exceeds the predetermined threshold value. The reset command is output in a short cycle, and the watchdog timer
Each time the reset command is received, the measured value is reset.
Therefore, the measured value does not exceed the predetermined threshold value, and the runaway detection signal is not issued to the recovery means. On the other hand, when a program runaway occurs and the reset command means does not output the reset command to the watchdog timer normally, the measured value of the watchdog timer exceeds a predetermined threshold value.
The watchdog timer outputs a runaway detection signal to the recovery means. In this way, the runaway of the program can be detected.

[0017]

According to the electronic device of the present invention, the operation for restoring the operation of the device to the operation before the program runaway is unnecessary, and the original control processing is not delayed during the operation of the device. The control circuit can be executed, the configuration of the control circuit is simple, and the increase in cost required for the control circuit can be suppressed.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention applied to the audio equipment shown in FIG. 1 will be specifically described below with reference to the drawings. In an audio device (1) according to the present invention, as shown in FIG. 1, a microcomputer (2) has a tuner block having a tuner function for radio broadcasting.
(3), a CD block (4) having a CD reproducing function, an operation key block (5) having an information input function, and a display block (6) having an information display function are connected. Each of these blocks (3) to (6) is composed of a plurality of circuits, and these plurality of circuits are connected to the microcomputer (2).
The operation is controlled by. Further, the microcomputer (2) has a power supply circuit (8) via a reset circuit (7).
Is connected, and the power supply circuit (8) is a commercial power supply (not shown).
In the state where the power supply circuit (8) is connected to the microcomputer, power is supplied to the microcomputer (2), the tuner block (3), the CD block (4), the operation key block (5) and the display block (6). Supplied.

The microcomputer (2) comprises a CPU (20), to which the I / O board (21) and peripheral hardware (22) such as a timer and an interrupt processing mechanism are connected. The tuner block on the I / O board (21)
(3), CD block (4), operation key block (5) and display block (6) are connected. Further, when the reset circuit (7) is connected to the CPU (20) and the power supply circuit (8) is connected to the commercial power supply, the reset circuit (7) detects this state and the CPU (20) Supply a reset signal to.
Also, a watchdog timer (23) is connected to the CPU (20). Watchdog timer (23) is CPU (20)
When the time measurement value exceeds a predetermined threshold value, the interrupt signal is supplied to the CPU (20) at that time. Therefore, when the program is running normally, the CPU (20) supplies a clear signal to the watchdog timer (23) at a constant cycle, and the time measurement value of the watchdog timer (23) is at a constant cycle. Although it will be initialized to zero, the program runs away and the CPU (20) causes the watchdog timer (23)
If the clear signal is not normally supplied to the watchdog timer (23), the time measurement value of the watchdog timer (23) exceeds the predetermined threshold, and the watchdog timer (2
An interrupt signal is supplied from 3) to the CPU (20).

An information register (24) is connected to the CPU (20). The CPU (20), like the conventional audio equipment, executes the operation of writing the operation information representing the operating status in the information register (24) when the operating status of the equipment changes. As the operation information, for example, information indicating the on / off state of the power switch of the device body, the reproduction source A
Information indicating whether it is an M radio broadcast, an FM radio broadcast, or a CD. If the reproduction source is an AM radio broadcast or an FM radio broadcast, information indicating the reception frequency of the tuner block (3), the reproduction source is a CD. In some cases, information indicating the reproduction / stop state, address information indicating the reproduction position, etc. are written.

Further, the CPU (20) has a first flag register.
(25) and the second flag register (26) are connected. The first flag register (25) has a value of "0" indicating that writing of information to the information register (24) is permitted, or "1" indicating that writing is prohibited.
The write permission / prohibition flag which takes any one of the values is stored. In the state where the program is normally executed, a write request is made to the information register (24) when the write permission / prohibition flag is "0", so the operation information is written to the information register (24). However, if a write request is made to the information register (24) while the program is running out of control, it is highly possible that the write permission / prohibition flag has a value of "1". No information is written to the register (24). On the other hand, the second flag register (26) has a value of "1" indicating that a program runaway has been detected, or a value of "0" indicating that a program runaway has not been detected. The detection flag is stored.

The CPU (20) rewrites the runaway presence / absence detection flag to a value of "0" when receiving a reset signal from the reset circuit (7), that is, when a commercial power source is connected to the power source circuit (8). On the other hand, when an interrupt signal is received from the watchdog timer (23), that is, when a program runaway is detected, the runaway presence / absence detection flag is rewritten to a value of "1". When the runaway presence / absence detection flag has a value of “0”, the CPU (20)
(3), the CD block (4), the operation key block (5), and the display block (6) are respectively set to the state of a plurality of circuits in the initial state in which the plurality of circuits have stopped the operation, runaway When the detection presence / absence flag has a value of "1", the program operates before the runaway of the plurality of circuits based on all or part of the operation information written in the information register (24). Restore operation.

FIG. 2 shows a control procedure executed by the CPU (20) in a state where the device body is connected to a commercial power source. As shown in the figure, first, in step S1, necessary initial processing such as setting of each port is performed, and then in step S2, the runaway detection presence / absence flag (“WD_FLAG”) has a value of “0” or a value of “1”. Which of the two is taken is determined. If it is determined that the runaway detection presence / absence flag has a value of "0", the process proceeds to step S3,
After setting the states of a plurality of circuits respectively constituting the tuner block (3), the CD block (4), the operation key block (5) and the display block (6) to the initial state, step S6
Move to. On the other hand, if it is determined that the runaway detection presence / absence flag has a value of "1", the process proceeds to step S4, and the value of the runaway detection presence / absence flag is rewritten to "0". Then, based on all or part of the operation information written in the information register (24), the tuner block (3), C
After the operations of the plurality of circuits respectively constituting the D block (4), the operation key block (5) and the display block (6) are restored to the operations before the program runaway, the process proceeds to step S6.

In step S6, the control process for the tuner block (3), the CD block (4), the operation key block (5) and the display block (6) is executed according to the user's operation, and then the device is operated in step S7. The operation information indicating the operation state of is written in the information register (24). Succeedingly, in a step S8, a clear signal is outputted to the watchdog timer (23), and thereafter, the process returns to the step S6.

FIG. 3 shows the watchdog timer (23) to C
It shows an interrupt processing procedure executed by the CPU (20) when an interrupt signal is supplied to the PU (20). First, in step S11, the runaway detection presence / absence flag is rewritten to a value of "1", and then the step In S12, a reset command to the effect that the process should move to step S1 shown in FIG.

In the audio device according to the present invention,
When a commercial power supply is connected to the power supply circuit (8) shown in FIG. 1 and a reset signal is supplied from the reset circuit (7) to the CPU (20), first, the operation information written in the information register (24) At the same time as the initialization, the runaway detection presence / absence flag stored in the second flag register (26) is initialized to a value of "0". Subsequently, after the necessary initial processing is performed in step S1 of FIG. 2, it is determined in step S2 that the runaway detection presence / absence flag has a value of "0", and the tuner block (3 ), CD block (4),
The states of a plurality of circuits respectively constituting the operation key block (5) and the display block (6) are set to the initial state. In this way, the device state is set to the initial state. Then, the processes of steps S6 to S8 are repeatedly executed at a cycle of, for example, 10 msec. As a result, when there is a change in the operating state of the device, the operating information indicating the operating state is written to the information register (24) and the clear signal is supplied to the watchdog timer (23) at a constant cycle. become.

Thereafter, if a situation occurs in which the program runaway occurs and the processing in steps S6 to S8 is not executed, the CPU (20) causes the watchdog timer (2
The supply of the clear signal to 3) is stopped and the time measured value of the watchdog timer (23) exceeds a predetermined threshold value, and the interrupt signal is supplied from the watchdog timer (23) to the CPU (20).

When an interrupt signal is supplied to the CPU (20),
After the value of the runaway detection presence / absence flag is rewritten to "1" in step S11 of FIG. 3, the reset command is executed in step S12, the process proceeds to step S1 of FIG. 2, and the initial process is performed in step S1. Be done. Then, in step S2, it is determined that the runaway detection presence / absence flag has a value of "1", and in step S3 the tuner block (3), the CD block (4), the operation key block (5) and the display block. The operation of the plurality of circuits respectively constituting (6) is restored to the operation before the program runaway. In this way
The operation of the equipment is restored to the operation before the program runaway.

In the audio device according to the present invention,
As mentioned above, when a commercial power source is connected to the main unit,
When the runaway of the program is detected while the state of the device is set to the initial state, the operation of the device is restored to the operation before the program runaway. For example, when a program runaway occurs during the reproduction of a CD, the reproduction of the CD is started from the reproduction position at that time. Therefore, a recovery operation for recovering the operation of the device to the operation before the program runaway is unnecessary.

Further, in the microcomputer (2), in order to restore the operation of the device to the operation before the program runaway, a new process for storing information other than the operation information is not performed, so that the device is operating. There is no delay in the original control processing. Further, a save memory for saving the values of the program counter and a plurality of registers, and a save / restore control circuit for performing a save process and a replace process between the program counter and a plurality of registers and the save memory are unnecessary. Therefore, the configuration of the control circuit is simple and the cost required for the control circuit is suppressed.

Further, as described above, when a write request is issued to the information register (24) while the program is running out of control, it is highly possible that the write permission / prohibition flag has a value of "1". , It is extremely unlikely that the operation information written in the information register (24) will be rewritten between the time the program runaway occurs and the time when the interrupt signal is supplied to the CPU (20). It is possible to prevent a situation in which the operation of the device cannot be restored to the operation before the program runaway due to the rewriting.

The configuration of each part of the present invention is not limited to the above-described embodiment, and various modifications can be made within the technical scope described in the claims. For example, although the present invention is applied to the audio device in the above embodiment, the present invention is not limited to this and can be applied to various electronic devices including a control circuit such as a microcomputer. Further, as the method for detecting the runaway of the program, the detection method using the watchdog timer is adopted, but other known detection methods can be adopted. Further, it is also possible to adopt a configuration in which a reset button is provided in the electronic device and the state of the device is set to the initial state when the reset operation is performed on the reset button.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an audio device embodying the present invention.

[Fig. 2] CPU with commercial power supply connected to the device body
6 is a flowchart showing a control procedure executed by

FIG. 3 is a flowchart showing an interrupt processing procedure executed by the CPU when an interrupt signal is supplied from the watchdog timer to the CPU.

[Explanation of symbols]

(1) Audio equipment (2) Microcomputer (23) Watchdog timer (24) Information register (25) First flag register (26) Second flag register (3) Tuner block (4) CD block (5) Operation key block (6) Display block

Claims (5)

[Claims] 1. An electronic device in which the operation of the device is controlled by a control circuit having a program runaway detection function, and one or a plurality of pieces of operation information indicating the operating state of the device are stored, An electronic device, characterized in that, when a runaway is detected, the device includes recovery means for restoring the operation of the device to the operation before the program goes out of control based on all or part of the stored operation information. 2. The control circuit includes: operation information storage means for storing operation information; and write permission / prohibition information storage means for storing write permission / prohibition information indicating permission / prohibition of writing information to the operation information storage means. Writing information to write to the operation information storage means only when it is determined that writing of information to the operation information storage means is permitted based on the write permission / prohibition information The electronic device according to claim 1, further comprising: 3. The control circuit restoring means restores the operation of the device to the operation before the program goes out of control when a program runaway is detected, or when the power of the device body is turned on, or The electronic device according to claim 1 or 2, wherein a state of the device is set to an initial state when a reset operation is performed. 4. The control circuit has a first value indicating that a program runaway has been detected,
Alternatively, the flag storage means for the runaway detection presence / absence flag, which takes any one of the second values indicating that it has not been detected, and the device main body when the power is turned on or when the reset operation is performed, The recovery means includes a recovery command means for outputting a recovery operation start command to the recovery means, and the recovery means receives the recovery operation start command, and the runaway detection presence / absence flag has either a first value or a second value. Determining means for determining whether or not a value is taken, and when it is determined that the runaway detection presence / absence flag takes a first value, the operation of the device is restored to the operation before the program goes out of control, and the runaway is performed. While rewriting the presence / absence flag to the second value, when it is determined that the runaway detection presence / absence flag has the second value, the recovery processing means for setting the state of the device to the initial state, and the runaway of the program. 4. The electronic device according to claim 3, further comprising: an interrupt processing unit that rewrites the runaway detection presence / absence flag to a first value and outputs a recovery operation start command to the determination unit when is detected. 5. The control circuit measures the passage of time, resets the measured value to an initial value when receiving a reset command, and informs the restoration means when the measured value exceeds a predetermined threshold value. A watchdog timer that outputs a runaway detection signal, and a reset command unit that outputs a reset command to the watchdog timer at a cycle shorter than the time from when the measured value exceeds a predetermined threshold value to the measured value. The electronic device according to any one of claims 1 to 4, further comprising: