JPH083740B2 - Control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device including a microcomputer.

(Prior Art) A control device equipped with a microcomputer inspects whether or not the performance is normal at the time of product shipment. Conventionally, this inspection is carried out using a normal control program of a microcomputer. However, in this method, since the input / output is performed imitating the normal control, a great amount of time and labor is spent on the inspection.

Therefore, in the control device described in Japanese Patent Laid-Open No. 57-13520, a program for the microcomputer is created so that the self-diagnosis mode can be executed separately from the normal control mode. The mode is executed to simplify the inspection.

(Problems to be Solved by the Invention) However, in the control device of the above publication, the program may run away due to noise or the like and enter the self-diagnosis mode during execution of the normal control mode after product shipment. ,
There is a drawback that the normal control is hindered because the self-diagnosis mode cannot be exited.

(Means for Solving Problems) The present invention has been made to solve the above problems, and (a) the normal control mode executing means, the self-diagnosis mode executing means, and the normal operation when receiving a reset signal. A microcomputer including a selection means for selecting one of a mode and a self-diagnosis mode, and (b) a reset signal is not output to the microcomputer when a program run signal is received from the microcomputer, and the microcomputer does not output a predetermined time. A watchdog timer that outputs a reset signal to the microcomputer when it does not receive a proclan run signal, and the normal control mode execution means is at a time interval shorter than the predetermined time during execution of normal control. A program run signal is output, and the self-diagnosis mode execution means performs self-diagnosis. The control device is characterized in that it is divided into several stages and executed, and in the final step of each stage, the state in which the program run signal is not output is maintained and the reset signal from the watchdog timer is waited for.

(Operation) When the program runs into the self-diagnosis mode due to noise or the like while executing the normal control mode, the program run signal is not output at the final step of any stage of the self-diagnosis mode. Since the state is maintained, the watchdog timer resets the microcomputer, and thereafter, the normal control mode is selected by the selection means of the microcomputer. Therefore, it is possible to immediately exit the self-diagnosis mode and return to the normal control mode.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings from FIG. 1 to FIG. Reference numeral 10 in FIG. 1 denotes a control unit (control device) used, for example, for fuel injection control of a vehicle. The control unit 10 includes a microcomputer 11 and a watchdog timer 12 connected to the microcomputer 11, and Built-in hardware (not shown) such as A / D converter. The control unit 10 has, for example, eight analog signal input terminals 13
..., six digital signal input terminals 14, ..., an input terminal 15 for inputting a signal from a rotation sensor for detecting engine rotation, and three control output terminals 16 ..., a display control output terminal 17 There is. Further, it has a large number of other input terminals and output terminals not shown. The terminals 13 to 17 of these control units are connected to the input / output ports of the microcomputer 11 directly or via an A / D converter or other hardware.

The microcomputer 11 can execute a normal control mode and a self-diagnosis mode as will be described later, and has a selection means for judging which mode should be executed based on the input condition. .

The microcomputer 11 also includes an output unit that outputs a mode determination signal Sm to the watchdog timer 12. That is, when the normal control mode is being executed, a pulse indicating a program run is intermittently output from the microcomputer 11 at short time intervals, and when the self-diagnosis mode is being executed, this pulse is not output and is at the L level. It remains. The output consisting of this pulse group and the L level becomes the mode discrimination signal Sm.

When the watchdog timer 12 receives pulses intermittently in the normal control mode, the watchdog timer 12 is reset at short intervals by the pulses.
When no pulse is received in the self-diagnosis mode without outputting the reset signal Sr, the reset signal Sr is output every predetermined time.

The control unit 10 having the above configuration performs self-diagnosis before shipping the product. In this case, as shown in FIG. 1, hardware for self-diagnosis is connected. More specifically, the input device 20 is connected to the analog signal input terminals 13 of the control unit 10. Further, the connection device 21 connects each one of the control output terminals 16 ... And each of the two digital signal input terminals 14. Further, the display device 22 is connected to the display control output terminal 17. The input terminal 15 is not connected to the rotation sensor but is grounded.

As shown in FIG. 2, the display device 22 has eight numerical display windows.
25, a mode lamp 26, and a failure code display window 27. Each numerical value display window 25 corresponds to each analog signal input terminal 13.

Next, the self-diagnosis control will be schematically described. The input device 20 sends specified analog input data to each analog signal input terminal 13. This analog input data differs for each analog signal input terminal 13. Control unit 10
Then, this analog input data is converted to digital and sent to the microcomputer 11. The microcomputer 11 determines whether or not each analog input data converted into digital data is within an allowable error range with respect to each specified value, that is, is substantially equal. If all of these analog input data are equal to the specified value,
This is one of the conditions for entering the self-diagnosis mode. Therefore, if there is a hardware failure such as an A / D converter or a connection failure, the self-diagnosis mode is not entered.

In the microcomputer 11, the engine speed is calculated based on the input signal to the input terminal 15.
In the hardware mounted state in the figure, the input terminal 15 is grounded, and therefore the result of calculation of the rotation speed is zero. This zero rotation speed is also one of the conditions for entering the self-diagnosis mode.

In addition, a signal is issued from the microcomputer 11 via one control output terminal 16 selected in advance, and at this time, the signal is sent to the microcomputer 11 via one digital input terminal 14 connected to the control output terminal 16. It is determined whether the input signal matches the level of the output signal. This coincidence of input and output is also one of the conditions for entering the self-diagnosis mode.

In the microcomputer 11, when all the rush conditions described above are satisfied, the selection means determines this and enters the self-diagnosis mode. At this time, the mode lamp 26 of the display device 22 is turned on. The inspector can confirm that the self-diagnosis mode is being executed by turning on the mode lamp 26. If the self-diagnosis mode is not entered, that is, if the mode lamp 26 does not light up, as described above, the A / D
It can be known that the converter etc. has failed. The analog input data converted into digital data is sent from the microcomputer 11 to the display device 22 and displayed in the numerical value display window 25. Therefore, the inspector can roughly know where a failure has occurred by comparing each displayed data with each specified value.

In the self-diagnosis mode, when a signal is sequentially output from each output port of the microcomputer 11 via the control output terminal 16, the level of the signal input to the microcomputer 11 via the corresponding two digital signal input terminals 14 is set. to decide. When the output is at the H level, the corresponding input is at the H level, and when the output is at the L level, if the corresponding input is at the L level, the input / output function of the microcomputer 11, between the microcomputer 11 and the terminals 14 and 16. It is diagnosed that there is no connection failure or hardware failure. If the output and input levels are different, diagnose that there is a failure. Then, the diagnosis result is displayed in the failure code display window 27 of the display device 22.
To display the code number. For example, if there is no failure, "00" is displayed, and if there is any failure, "01" ...
Display as "06". This failure code allows the inspector to roughly estimate the failure location.

When the self-diagnosis mode is being executed, the mode discrimination signal Sm is at L-level as described above, and the watchdog timer 12 causes the microcomputer to change at predetermined intervals.
The reset signal Sr is output to 11. Microcomputer
In 11, the mode is selected and the self-diagnosis mode is executed each time it is reset. It should be noted that each time the data is reset, data is displayed in the numerical display windows 25 one by one, and after this display is completed, the input / output check is performed once.
Do each one.

After the self-diagnosis, the control unit 10 configured as described above is shipped with the input device 20, the connection device 21, and the display device 22 removed if there is no abnormality, and is used, for example, for controlling a fuel injection device of an automobile. The fuel injection device includes a fuel injection pump and a governor, and the governor controls the position of a control member by an actuator to adjust the amount of fuel supplied from the fuel injection pump.

Hereinafter, the control of the fuel injection or the like, that is, the normal control will be briefly described. The analog signal input terminal 13 ...
Analog information about the amount of accelerator depression from the accelerator sensor, the water temperature of the engine, the position of the control member, etc. is input. These pieces of information are digitized by the A / D converter and input to the microcomputer 11.
Further, ON / OFF signals from various switches such as a starter switch are input to the digital signal input terminals 14 ...
To the microcomputer 11. Also, control output terminal
The 16 outputs a failure indicator lamp during normal control and an on / off signal to the engine preheating plug. The engine rotation signal from the rotation sensor is input to the input terminal 15. In addition, a control signal to an actuator for controlling the control member or the like is output from an output terminal (not shown) based on the engine speed, the accelerator pedal depression amount, and the like. The display control terminal 17 is not used in normal control.

When the normal control mode is being executed, the mode discrimination signal Sm from the microcomputer 11 consists of intermittent pulses, and the watchdog timer 12 is reset in a short time by this pulse. To microcomputer 11 reset signal Sr
Is not output. Therefore, the microcomputer 11 is not reset during execution of the normal control mode, and stable normal control can be performed.

When the program runs into the self-diagnosis mode due to noise or the like while executing the normal control mode, after a predetermined time has elapsed based on the L-level mode determination signal Sm, the watchdog timer 12 causes the micro The computer 11 is reset, and thereafter, it is determined whether the number of revolutions is zero, whether each analog input data matches the specified value, and one selected control output terminal 16 is selected.
The normal control mode is selected by determining whether or not the output from the input terminal and the input to the corresponding one digital signal input terminal 16 match. Normally, the engine speed is not zero in normal mode, and even if the engine speed is zero, all analog input data does not match the specified value, and there is nothing to do with the normal mode. Since the output and the input rarely coincide with each other, this selection allows the user to immediately exit the self-diagnosis mode and return to the normal control mode. In the case of determining the coincidence of the input and output, for example, the output for controlling the failure indicator lamp in the normal state is used as the output and the input from the starter switch is used as the input.

Next, the program in the microcomputer 11 will be described with reference to FIGS. 3 and 4. First, when the start signal or reset signal is received, step 100
Initialize the I / O port with. In the next step 101, it is determined whether the check RAM is the first set value or the second set value. If it is the second set value, it is determined that the normal control mode is being executed, the display pointer is reset in step 102, the check counter is reset in step 103, and step 1
After resetting the failure display register in 04, step 10
Initialize the system with 5 and finish the program,
Move to task management program.

If the check RAM has the first set value, it is temporarily determined that the self-diagnosis mode is being executed, and the numerical value of the display pointer is determined in step 106. If this numerical value is "10" or more, it is not a numerical value that can be taken during the self-diagnosis mode, and it is determined that the normal control mode is being executed, and steps 102 to 105 are executed. If the value is "9" or less, it is determined that the self-diagnosis mode is being executed, and the value of the check counter is determined in the next step 107. If this numerical value is "4" or more, it is determined that the numerical value cannot be taken during execution of the self-diagnosis mode, and the above steps 102 to 105 are executed.
If this numerical value is "3" or less, it is temporarily determined that the self-diagnosis mode is in progress, and the input / output check is executed in the following steps 108-111.

More specifically, in step 108, an H level signal is output to one control output terminal 16 selected in advance. And
In step 109, it is determined whether the input signal that has passed through one digital signal input terminal 14 corresponding to the control output terminal 16 is at the H level or the L level. If this input is at the L level unlike the output level, it is determined that the normal control mode is being executed, and steps 102 to 105 are executed. If the input is at H level, it is assumed that the self-diagnosis mode is set,
At 110, an L level signal is output to the control output terminal 16. Then, in step 111, the level of the input signal passed through the corresponding digital signal input terminal 14 is determined. If the input signal is at the H level unlike the output level, it is determined that the normal mode is being executed, and steps 102 to 105 are executed. If the input level is the L level, it is finally determined that the self-diagnosis mode is being executed, the system is initialized in the next step 112, the processing is terminated, and the task management program is entered. Therefore, during execution of the self-diagnosis mode, the display pointer, check counter, and failure display register used for this self-diagnosis are not reset.

When the initialization program ends, a task start signal is generated in the task management program. Then, the task (TASK1) of FIG. 4 having the shortest activation cycle is executed. More specifically, in step 120, it is determined whether the engine speed is zero. As described above, in the self-diagnosis mode, no signal is input to the input terminal 15 from the rotation sensor, and the rotation speed is zero. Therefore, when it is not zero, it is determined that the normal control mode is being executed, and step 12
When 1 is set to the check RAM as the second set value indicating that the normal control mode is being executed, the task is ended, and
Jump to the program that executes the normal control mode.

When the engine speed is zero, it is temporarily determined that the self-diagnosis mode is being executed, and in the next step 122, it is determined whether or not each input analog input data substantially matches the set value. If they do not match, it means that the A / D converter or the like has failed or the normal control mode is being executed. Therefore, at this time also, step 121 is executed, and then the normal control mode is entered.

If each analog input data matches the set value in step 122, it is determined that the self-diagnosis mode is being executed, and the input / output check is executed in steps 123 to 126. More specifically, in step 123, an H level signal is output to one control output terminal 16 selected in advance. Then, in step 124, it is determined whether the input signal via one digital signal input terminal 14 corresponding to the control output terminal 16 is at the H level or the L level. If this input is at the L level unlike the output level, it is determined that the normal control mode is being executed, and the above step 121 is executed. If the input is at H level, it is assumed that the self-diagnosis mode is set, and the next step
At 125, an L level signal is output to the control output terminal 16. Then, in step 126, the level of the input signal passed through the corresponding digital signal input terminal 14 is determined. If the input signal is at the H level, unlike the output level, the step 121 is executed assuming that the normal mode is being executed.

If the input signal is at the L level, it is finally determined that the self-diagnosis mode is being executed, and in step 130 the check RAM is set to the first set value indicating that the self-diagnosis mode is being executed. Run. That is, in step 131, a control signal for pulling down the control member (stopping the engine) by the governor actuator is output. This is for ensuring safety when the self-diagnosis mode is entered due to a program runaway during normal control, that is, while the vehicle is traveling.

Next, in step 132, it is determined whether or not all the input / output checks have been completed, that is, whether the check counter has a value equal to the number of control output terminals 16, that is, "3".

If the check is not completed, it is determined in step 133 whether the analog input data display is completed, that is, whether the display pointer has the number of analog signal input terminals 13, that is, "9". If not finished, the following steps 134 to 138 are executed. These steps 134 to 138 are for turning on the mode lamp 26 and sequentially displaying the analog input data on each numerical display window 25 of the display device 22. More specifically, in step 134, it is determined whether the display pointer is zero. When it is zero, the mode lamp 26 is turned on in step 135. Therefore, the mode lamp 26 lights up from the beginning of execution of the self-diagnosis mode to indicate that the self-diagnosis mode is in effect. If the display pointer is not zero, step 13
In step 6, the analog input data from the input terminal 13 corresponding to the numerical value written in the display pointer is displayed in the numerical value display window 25. After execution of step 135 or step 136, the display pointer is incremented in step 137. By repeating these steps 134 to 137, the analog input data can be sequentially displayed on the numerical display window 25.

The next step 138 is a no-operation, which forms an infinite loop and waits for the output of the reset signal Sr from the watchdog timer 12. Therefore, the microcomputer 11 is reset every time the analog input data is displayed in the one numerical value display window 25.

When all the input / output checks are not completed and the analog input data display is completed, the input / output check is executed in steps 140 to 147. More specifically, in step 140, an H level signal is output to the control output terminal 16 designated by the check counter. Then, in step 141, two digital signal input terminals corresponding to the control output terminal 16
It is determined whether the input signal passing through 14 is at H level or L level.
If either of the two inputs is at the L level, which is different from the output level, it is determined that there is a failure and the corresponding bit of the failure display register is set at step 142. If the two inputs are H level, an L level signal is output to the control output terminal 16 designated by the check counter in step 143. Then, in step 144, the level of the input signal passed through the two digital signal input terminals 14 corresponding to the control output terminal 16 is judged. If the input signal is at the H level unlike the output level, the corresponding bit of the failure display register is set at step 145. In the next step 146, the check counter is incremented. These steps 140-1
By repeating 46, input / output checks can be performed in order.

The next step 147 is no operation, forming an infinite loop and waiting for the output of the reset signal Sr from the watchdog timer 12. Therefore, the microcomputer 11 is reset each time one input / output check is performed.

When all I / O checks are complete, step 132
Then, this is judged and steps 150 to 152 are executed. That is, in step 150, a failure code signal is output to the display device 22 based on the set or reset state of each bit of the failure display register to display the failure code in the failure code display window 27. In the next step 151, the display pointer and the check counter are reset, and in step 152, no operation is performed to form an infinite loop, and the reset signal Sr from the watchdog timer 12 is waited for.

Since the task shown in FIG. 4 has the shortest activation cycle, the task shown in FIG. 3 is always executed with priority after the initialization. Therefore, the self-diagnosis mode is repeatedly executed every time the microcomputer 11 is reset.

If the self-diagnosis mode is entered due to noise or the like while executing the normal control mode, step 138,
An infinite loop is formed in any of 147 and 152 to wait for a reset signal, and when reset, the program of FIG. 3 is executed and then steps 120, 122 and 12 of the program of FIG. 4 are executed.
4, or in step 126, select the normal mode,
You can immediately exit the self-diagnosis mode.

The present invention is not limited to the above-mentioned embodiment and various modes are possible.

(Effects of the Invention) As described above, in the present invention, the microcomputer program is created so that the self-diagnosis mode can be executed separately from the normal control mode, and the self-diagnosis mode should be executed when the product is shipped. Therefore, the inspection can be simplified. In addition, even if the program runs into the self-diagnosis mode due to noise or the like during the normal control, it is possible to immediately exit the self-diagnosis mode and prevent the normal control from being disturbed.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a block diagram of a control device and peripheral hardware during execution of a self-diagnosis mode, and FIG. 2 is a display device. A front view, FIG. 3 is a flowchart showing an initialization processing program, and FIG. 4 is a flowchart showing a program for executing a self-diagnosis mode. 10 ... Control unit (control device), 11 ... Microcomputer, 12 ... Watchdog timer, Sm ...
… Mode discrimination signal, Sr …… Reset signal.

Claims (1)

[Claims] (A) A microcomputer including a normal control mode execution means, a self-diagnosis mode execution means, and a selection means for selecting one of a normal mode and a self-diagnosis mode when a reset signal is received, B) A watchdog timer that does not output a reset signal to the microcomputer when receiving a program run signal from the microcomputer, and outputs a reset signal to the microcomputer when it does not receive a prog run signal from the microcomputer for a predetermined time. The normal control mode executing means outputs a program run signal at a time interval shorter than the predetermined time while executing the normal control, and the self-diagnosis mode executing means performs self-diagnosis in a plurality of stages. Divide and execute the program run signal at the final step of each stage While maintaining the state in which no force control apparatus characterized by waiting for a reset signal from the watchdog timer.