KR20240010313A - System and method for testing input circuit of electronic control unit - Google Patents

Abstract

According to the present invention, an input circuit test system of an electronic control device comprises: an input circuit including at least one resistor and at least one capacitor; a microprocessor measuring a charging voltage and a discharging voltage of the capacitor of the input circuit; a driving circuit selectively applying a VCC voltage and a GND voltage to an input terminal of the input circuit according to control of the microprocessor; and a watchdog timer that applies a driving signal to the driving circuit. The microprocessor transmits a watchdog signal required from the watchdog timer at predetermined time intervals to activate the driving signal, detects a charging voltage value of the capacitor after a preset time when the VCC voltage is applied to the input circuit, detects a discharging voltage value of the capacitor after a preset time when the GND voltage is applied to the input circuit, and transmits a difference between the charging voltage value and the discharging voltage value to an external reading device when a charging/discharging test time required according to time constants of the resistor and the capacitor exceed a disable time according to accumulation of error counts of the watchdog timer.

Description

{System and method for testing input circuit of electronic control unit}

The present invention relates to a system and method for inspecting the function of an electronic control device, and more specifically, to a system and method for inspecting an input circuit of an electronic control device.

Generally, vehicles are equipped with an electronic control unit (ECU) that monitors and controls the status of the engine, automatic transmission, ABS, etc. to improve vehicle control and safety according to driving conditions.

The electronic control device controls functions such as engine ignition timing, fuel injection, idling, and limit value settings, and can control overall aspects related to vehicle driving, such as the drive system, braking system, and steering system.

Patent No. 10-1515011, which is a prior art, discloses a system and method for integrated inspection of the functions of the input circuit, microprocessor, and watchdog timer that constitute the electronic control device. According to the prior literature, before the functional test of the electronic control device begins, the microprocessor stops the operation of the watchdog timer and performs the test.

However, if the operation of the watchdog timer is stopped every time a function is checked as above, the cycle time may increase depending on the control time of the watchdog timer and problems with system stability may occur. Additionally, if the resistance of the input circuit and the time constant of the capacitor are large, the time required for functional testing may be longer than a certain amount of time, making testing impossible in some cases. Additionally, after the functional test, it takes time to enable the watchdog timer again and wait until the error count decreases.

Registered Patent No. 10-1515011 (announced on May 4, 2015)

The technical problem to be achieved by the present invention is to provide an electronic control device that can test the function of an input circuit despite the test time required according to the resistance of the input circuit and the time constant of the capacitor without stopping the operation of the watchdog timer. The purpose is to provide an input circuit inspection system and method.

An input circuit inspection system for an electronic control device according to the present invention for solving the above technical problem includes an input circuit including at least one resistor and a capacitor; a microprocessor that measures the charging and discharging voltages of the capacitor of the input circuit; a driving circuit that selectively applies VCC voltage and GND voltage to the input terminal of the input circuit under the control of the microprocessor; and a watchdog timer that applies a driving signal to the driving circuit, wherein the microprocessor transmits a watchdog signal required by the watchdog timer at regular time intervals to activate the driving signal, and transmits a watchdog signal required by the watchdog timer at regular time intervals, and transmits a watchdog timer to the input circuit. Detects the charging voltage value of the capacitor after the VCC voltage is applied and a preset time, detects the discharge voltage value of the capacitor after a preset time after the GND voltage is applied to the input circuit, and determines the time constant of the resistor and capacitor. Accordingly, when the required charge/discharge test time exceeds the disable time according to the error count accumulation of the watchdog timer, the difference between the charge voltage value and the discharge voltage value is transmitted to an external reading device.

The microprocessor, when the charge/discharge test time required according to the time constants of the resistor and the capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer, determines the charge voltage value and the discharge voltage value. It can be transmitted to the external reading device.

The microprocessor detects the charging voltage value of the capacitor after a preset time after the VCC voltage is applied to the input circuit, and detects the discharge voltage value of the capacitor after a preset time after the GND voltage is applied to the input circuit. The time taken may be within the disable time according to the accumulation of error counts of the watchdog timer.

If the charge/discharge test time required according to the time constants of the resistor and capacitor exceeds the disable time according to the error count accumulation of the watchdog timer, the charge voltage value is the voltage before charging is completed, and the discharge voltage value is This may be the voltage before discharge is complete.

If the charge/discharge test time required according to the time constants of the resistor and the capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer, the charge voltage value is the charging completed voltage, and the discharge voltage value is It may be a voltage at which discharge has been completed.

The external reading device may determine whether the input circuit is normal based on the difference between the charging voltage value and the discharging voltage value.

The input circuit inspection method of an electronic control device according to the present invention for solving the above technical problem includes an input circuit including at least one resistor and a capacitor, and a microprocessor for measuring the charge voltage and discharge voltage of the capacitor of the input circuit. and an input circuit of an electronic control device including a driving circuit that selectively applies a VCC voltage and a GND voltage to the input terminal of the input circuit under the control of the microprocessor, and a watchdog timer that applies a driving signal to the driving circuit. A method of checking, comprising: connecting an input terminal of the input circuit and an output terminal of the driving circuit; activating the driving signal by transmitting a watchdog signal required by the watchdog timer at regular time intervals; Controlling the driving circuit so that a VCC voltage is applied to the input terminal of the input circuit, and detecting the charging voltage value of the capacitor after a preset time; Controlling the driving circuit so that a GND voltage is applied to the input terminal of the input circuit, and detecting the discharge voltage value of the capacitor after a preset time; And when the charge/discharge test time required according to the time constant of the resistor and the capacitor exceeds the disable time according to the error count accumulation of the watchdog timer, an external reading device determines the difference between the charge voltage value and the discharge voltage value. Characterized in that it includes the step of transmitting to.

The input circuit inspection method of the electronic control device includes, when the charging and discharging inspection time required according to the time constants of the resistor and the capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer, the charging voltage value And it may further include transmitting the discharge voltage value to the external reading device.

The time taken to detect the charging voltage value of the capacitor after the VCC voltage is applied to the input circuit and a preset time, and to detect the discharge voltage value of the capacitor after the GND voltage is applied to the input circuit and a preset time is, It may be within the disable time according to the error count accumulation of the watchdog timer.

If the charge/discharge test time required according to the time constants of the resistor and capacitor exceeds the disable time according to the error count accumulation of the watchdog timer, the charge voltage value is the voltage before charging is completed, and the discharge voltage value is This may be the voltage before discharge is complete.

If the charge/discharge test time required according to the time constants of the resistor and the capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer, the charge voltage value is the charging completed voltage, and the discharge voltage value is It may be a voltage at which discharge has been completed.

The method of inspecting the input circuit of the electronic control device may further include the step of the external reading device determining whether the input circuit is normal based on the difference between the charging voltage value and the discharging voltage value.

According to the present invention described above, the function of the resistance and capacitor of the input circuit can be tested despite the test time required according to the time constant of the resistance and capacitor of the input circuit without stopping the operation of the watchdog timer.

Figure 1 shows the configuration of an input circuit inspection system for an electronic control device according to an embodiment of the present invention.
Figure 2a shows an example of the resistor and capacitor of the input circuit.
Figure 2b shows charge/discharge characteristics according to the resistance and capacitor of Figure 2a.
Figure 3a shows another example of a resistor and capacitor in an input circuit.
FIG. 3B shows charging and discharging characteristics according to the resistor and capacitor of FIG. 3B and charging and discharging voltage values detected according to an embodiment of the present invention.
Figure 4 shows a flowchart of a method for inspecting an input circuit of an electronic control device according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description and the accompanying drawings, substantially the same components are denoted by the same symbols to avoid redundant description. Additionally, when describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Figure 1 shows the configuration of an input circuit inspection system for an electronic control device according to an embodiment of the present invention.

The input circuit inspection system of the electronic control device according to this embodiment includes an electronic control device consisting of an input circuit 10, a microprocessor 20, a driving circuit 30, and a watchdog timer 40, and the electronic control device. and an external reading device 60 connected through a network 50.

The input circuit 10 includes at least one resistor and a capacitor. Here, in order to test the function of the input circuit 10, the input terminal of the input circuit 10 may be connected to the output terminal of the driving circuit 30.

The driving circuit 30 selectively applies the VCC voltage and the GND voltage to the input terminal of the input circuit 10 under the control of the microprocessor 20. Specifically, the driving circuit 30 may be composed of a power source for selectively applying the VCC voltage and the GND voltage and a switch for switching between the power sources, and may be configured to use the VCC power or the GND power according to the control of the microprocessor 20. Perform a switching operation so that this is output.

The microprocessor 20 measures the charging and discharging voltages of the input circuit 10. Specifically, the microprocessor 20 may detect the charging voltage value of the capacitor C ₂ after the VCC voltage is applied to the input circuit 10 by the driving circuit 30 and a preset time. Additionally, the microprocessor 20 may detect the discharge voltage value of the capacitor C ₂ after the GND voltage is applied to the input circuit 10 by the driving circuit 30 and a preset time.

The watchdog timer 40 performs a function of detecting malfunction of the microprocessor 20. For example, the watchdog timer 40 operates the microprocessor (20) within a preset certain time (watchdog time) in order to prevent task processing from being delayed due to an error occurring while the microprocessor 20 is performing a specific assigned task. 20) Receive the watchdog signal from. If a watchdog signal is not received from the microprocessor 20 within the watchdog time, the watchdog timer 40 transmits a reset signal to the microprocessor 20 according to the error count accumulation to prevent process processing due to an error. Delays can be prevented.

The microprocessor 20 transmits the watchdog signal required by the watchdog timer 40 at regular time intervals (watchdog time). If this watchdog signal is normally transmitted more than a few times, the watchdog timer 40 generates an error. As the count decreases, a driving signal (enable signal) that activates the driving circuit 30 is generated. When a driving signal is generated in the watchdog timer 40, it is transmitted to the driving circuit 30 and the driving circuit 30 is in an operable state.

As described above, in the prior art, before the functional test of the electronic control device begins, the operation of the watchdog timer 40 is stopped and the test is performed. However, if the operation of the watchdog timer 40 is stopped every time a function is checked, the cycle time may increase depending on the control time of the watchdog timer 40 and problems with system stability may occur.

Additionally, if the time constant of the resistance and capacitor of the input circuit 10 is large, the functional test may require a certain amount of time, making the test impossible.

FIG. 2A shows an example of the resistance and capacitor of the input circuit 10, and FIG. 2B shows charging and discharging characteristics according to the resistance and capacitor of FIG. 2A. Referring to FIGS. 2A and 2B, the time constant of the resistor (R ₂ ) and the capacitor (C ₂ ) is about 0.324 ms, allowing charging and discharging to be completed within about 7.5 ms. Assuming that the time for the error count to increase by 1 in the watchdog timer 40 is 3.7 ms and that the enable signal disappears when the error count reaches 5, the disable time due to error count accumulation is 3.7 ms × 5 = 18.5 ms. It becomes. Therefore, in the case of the resistor (R ₂ ) and capacitor (C ₂ ) as shown in FIG. 2A, inspection is possible because the required charging and discharging inspection time does not exceed the disable time due to the accumulation of error counts of the watchdog timer 40. Of course, the disable time according to error count accumulation can be determined in various ways depending on the specifications or design of the watchdog timer 40.

Figure 3a shows another example of the resistor and capacitor of the input circuit, and Figure 3b shows charge and discharge characteristics according to the resistor and capacitor of Figure 3b. Referring to FIGS. 3A and 3B, the time constant of the resistor (R ₂ ) and the capacitor (C ₂ ) is about 47 ms, and the time required to complete charging and discharging is about 550 ms. Therefore, the charge/discharge test cannot be performed within the disable time of 18.5 ms due to the accumulation of error counts of the watchdog timer 40.

Accordingly, in an embodiment of the present invention, the operation of the watchdog timer 40 is not stopped, and the charge/discharge inspection time required according to the resistance of the input circuit 10 and the time constant of the capacitor is adjusted to the error count accumulation of the watchdog timer. Depending on the case where the disable time is not exceeded and when it is exceeded, the charge/discharge test is performed using different methods of the first test mode or the second test mode. The time taken for the charge/discharge test, whether in the first test mode or the second test mode, is within the disable time according to the accumulation of error counts of the watchdog timer.

The first test mode is a case where the charge/discharge test time required according to the resistance of the input circuit 10 and the time constant of the capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer. In the first test mode, the microprocessor 20 detects the fully charged charging voltage value of the capacitor after a preset time after the VCC voltage is applied to the input circuit 10, and the GND voltage is applied to the input circuit 10. After the set time, the discharge voltage value of the capacitor when discharge is completed is detected. Then, the microprocessor 20 transmits the charging voltage value and the discharging voltage value to the external reading device 60, and the external reading device 60 determines whether the input circuit 10 is normal based on the charging voltage value and the discharging voltage value. decide.

The second test mode is when the charging/discharging test time required according to the resistance of the input circuit 10 and the time constant of the capacitor exceeds the disable time according to the error count accumulation of the watchdog timer. In the second test mode, the microprocessor 20 detects the charging voltage value before the charging of the capacitor is completed after a preset time after the VCC voltage is applied to the input circuit 10, and the GND voltage is applied to the input circuit 10. After a preset time, the discharge voltage value before the discharge of the capacitor is completed is detected. For example, as shown in FIG. 3B, a charging voltage of approximately 2.2V is detected before completion of charging, and a discharge voltage of approximately 1.2V is detected before completion of discharging. Then, the microprocessor 20 calculates the difference between the charging voltage value and the discharging voltage value and transmits it to the external reading device 60, and the external reading device 60 operates an input circuit based on the difference between the charging voltage value and the discharging voltage value. Determine whether (10) is normal. For example, if the difference between the charging voltage value and the discharging voltage value is within a certain normal range, it is determined to be normal.

In one embodiment, the first test mode and the second test mode are based on the charging and discharging test time required according to the time constant of the resistance and capacitor of the input circuit 10, which is the test target, and the error count accumulation of the watchdog timer 40. It can be set by the user by comparing the disable time. In this case, the input circuit inspection system of the electronic control device may be provided with a user interface for setting the first inspection mode and the second inspection mode.

In another embodiment, the values or time constants of the resistance and capacitor of the input circuit 10 are input, and logic or a lookup table is configured to calculate the required charge/discharge test time according to the time constants of the resistance and capacitor, so that the microprocessor The first test mode and the second test mode can be selected by comparing the required charge/discharge test time calculated by (20) with the disable time according to the error count accumulation of the watchdog timer (40). In this case, the input circuit inspection system of the electronic control device may be provided with a user interface for receiving the values or time constants of the resistance and capacitor of the input circuit 10.

Figure 4 shows a flowchart of a method for inspecting an input circuit of an electronic control device according to an embodiment of the present invention.

In step 410, the input terminal of the input circuit 10 and the output terminal of the driving circuit 30 are electrically connected.

In step 420, the watchdog timer 40 applies a driving signal (enable signal) to the driving circuit 30. Specifically, when the microprocessor 20 normally transmits the watchdog signal to the watchdog timer 40 more than a few times, the watchdog timer 40 generates a drive signal to activate the drive circuit 30 as the error count decreases. It is applied to the driving circuit 30.

In step 430, it is determined whether the charge/discharge test time required according to the resistance of the input circuit 10 and the time constant of the capacitor exceeds the disable time according to the error count accumulation of the watchdog timer 40, and if it does not exceed the disable time according to the error count accumulation of the watchdog timer 40. Steps 440 to 455 are performed as the first mode, and if it exceeds, steps 460 to 480 are performed as the second mode.

If the charge/discharge test time required according to the resistance of the input circuit 10 and the time constant of the capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer 40, in step 440, the microprocessor 20 Controls the driving circuit 30 so that the VCC voltage is applied to the input terminal of the input circuit 10, and detects the charging voltage value of the capacitor after a preset time. The charging voltage value detected here becomes the fully charged voltage.

In step 445, the microprocessor 20 controls the driving circuit 30 so that the GND voltage is applied to the input terminal of the input circuit 10, and detects the discharge voltage value of the capacitor after a preset time. The discharge voltage value detected here becomes the voltage at which discharge has been completed.

In step 450, the microprocessor 20 converts the detected charging and discharging voltage values into digital signals and transmits them to the external reading device 60 through the network 50.

In step 455, the external reading device 60 determines whether the input circuit 10 is normal based on the charging voltage value and the discharging voltage value.

If the charge/discharge test time required according to the resistance of the input circuit 10 and the time constant of the capacitor exceeds the disable time according to the error count accumulation of the watchdog timer 40, in step 460, the microprocessor 20 The driving circuit 30 is controlled so that the VCC voltage is applied to the input terminal of the input circuit 10, and the charging voltage value of the capacitor is detected after a preset time. The charging voltage value detected here is the voltage before charging is completed. Then, the microprocessor 20 converts the detected charging voltage value into a digital signal and stores it.

In step 465, the microprocessor 20 controls the driving circuit 30 so that the GND voltage is applied to the input terminal of the input circuit 10, and detects the discharge voltage value of the capacitor after a preset time. The discharge voltage value detected here is the voltage before discharge is completed. Then, the microprocessor 20 converts the detected discharge voltage value into a digital signal and stores it.

In step 470, the microprocessor 20 calculates the difference between the charging voltage value and the discharging voltage value.

In step 475, the microprocessor 20 transmits the difference between the charging voltage value and the discharging voltage value to the external reading device 60 through the network 50. At this time, the microprocessor 20 may also transmit information indicating that the transmitted value is the difference between the charging voltage value and the discharging voltage value.

In step 480, the external reading device 60 determines whether the input circuit 10 is normal based on the difference between the charging voltage value and the discharging voltage value. For example, the external reading device 60 may determine that the difference between the charging voltage value and the discharging voltage value is normal if it falls within a certain normal range.

According to an embodiment of the present invention, since the operation of the watchdog timer is not stopped, a cycle time according to the control time of the watchdog timer is not required, and the function of the watchdog timer is continuously performed, so the system can operate stably. . In addition, when the resistance and time constant of the capacitor of the input circuit are large, the function of the input circuit can be tested within the disable time due to the accumulation of error counts of the watchdog timer, despite the required test time.

Combinations of each block of the block diagram and each step of the flow diagram attached to the present invention may be performed by computer program instructions. Since these computer program instructions can be mounted on the processor of a general-purpose computer, special-purpose computer, or other programmable data processing equipment, the instructions performed through the processor of the computer or other programmable data processing equipment are shown in each block of the block diagram or flow diagram. Each step creates the means to perform the functions described. These computer program instructions may also be stored in computer-usable or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement a function in a particular manner, so that the computer-usable or computer-readable memory The instructions stored in can also produce manufactured items containing instruction means that perform the functions described in each block of the block diagram or each step of the flow diagram. Computer program instructions can also be mounted on a computer or other programmable data processing equipment, so that a series of operational steps are performed on the computer or other programmable data processing equipment to create a process that is executed by the computer, thereby generating a process that is executed by the computer or other programmable data processing equipment. Instructions that perform processing equipment may also provide steps for executing functions described in each block of the block diagram and each step of the flow diagram.

Additionally, each block or each step may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). Additionally, it should be noted that in some alternative embodiments it is possible for the functions mentioned in the blocks or steps to occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially simultaneously, or the blocks or steps may sometimes be performed in reverse order depending on the corresponding function.

The above description is merely an illustrative explanation of the technical idea of the present invention, and various modifications and variations will be possible to those skilled in the art without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope shall be construed as being included in the scope of rights of the present invention.

Claims (12)

An input circuit including at least one resistor and a capacitor;
a microprocessor that measures the charging and discharging voltages of the capacitor of the input circuit;
a driving circuit that selectively applies VCC voltage and GND voltage to the input terminal of the input circuit under the control of the microprocessor; and
It includes a watchdog timer that applies a driving signal to the driving circuit,
The microprocessor,
Activating the driving signal by transmitting the watchdog signal required by the watchdog timer at regular time intervals,
Detecting the charging voltage value of the capacitor after the VCC voltage is applied to the input circuit and a preset time, and detecting the discharge voltage value of the capacitor after a preset time after the GND voltage is applied to the input circuit,
If the charge/discharge test time required according to the time constants of the resistor and capacitor exceeds the disable time according to the error count accumulation of the watchdog timer, the difference between the charge voltage value and the discharge voltage value is read by an external reading device. An input circuit inspection system for an electronic control device characterized by transmitting. According to paragraph 1,
The microprocessor,
If the charge/discharge test time required according to the time constants of the resistor and capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer, the charge voltage value and the discharge voltage value are transmitted to the external reading device. An input circuit inspection system for an electronic control device characterized by transmitting. According to paragraph 1,
The microprocessor detects the charging voltage value of the capacitor after a preset time after the VCC voltage is applied to the input circuit, and detects the discharge voltage value of the capacitor after a preset time after the GND voltage is applied to the input circuit. An input circuit inspection system for an electronic control device, characterized in that the time taken is within the disable time according to the error count accumulation of the watchdog timer. According to paragraph 1,
If the charge/discharge test time required according to the time constants of the resistor and capacitor exceeds the disable time according to the error count accumulation of the watchdog timer, the charge voltage value is the voltage before charging is completed, and the discharge voltage value is An input circuit inspection system for an electronic control device, characterized in that the voltage is before completion of discharge. According to paragraph 1,
If the charge/discharge test time required according to the time constants of the resistor and the capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer, the charge voltage value is the charging completed voltage, and the discharge voltage value is An input circuit inspection system for an electronic control device, characterized in that the voltage is completely discharged. According to paragraph 1,
The external reading device determines whether the input circuit is normal based on the difference between the charging voltage value and the discharging voltage value. An input circuit including at least one resistor and a capacitor, a microprocessor for measuring the charge voltage and discharge voltage of the capacitor of the input circuit, and a VCC voltage and a GND voltage at the input terminal of the input circuit under the control of the microprocessor. In a method of inspecting an input circuit of an electronic control device including a drive circuit that selectively applies a drive signal, and a watchdog timer that applies a drive signal to the drive circuit,
Connecting the input terminal of the input circuit and the output terminal of the driving circuit;
activating the driving signal by transmitting a watchdog signal required by the watchdog timer at regular time intervals;
Controlling the driving circuit so that the VCC voltage is applied to the input terminal of the input circuit, and detecting the charging voltage value of the capacitor after a preset time;
Controlling the driving circuit so that a GND voltage is applied to the input terminal of the input circuit, and detecting the discharge voltage value of the capacitor after a preset time; and
If the charge/discharge test time required according to the time constants of the resistor and capacitor exceeds the disable time due to error count accumulation of the watchdog timer, the difference between the charge voltage value and the discharge voltage value is read by an external reading device. A method of inspecting an input circuit of an electronic control device, comprising the step of transmitting. In clause 7,
If the charge/discharge test time required according to the time constants of the resistor and capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer, the charge voltage value and the discharge voltage value are transmitted to the external reading device. A method of inspecting an input circuit of an electronic control device, further comprising the step of transmitting. In clause 7,
The time taken to detect the charging voltage value of the capacitor after the VCC voltage is applied to the input circuit and a preset time, and to detect the discharge voltage value of the capacitor after the GND voltage is applied to the input circuit and a preset time is, A method of inspecting an input circuit of an electronic control device, characterized in that it is within the disable time according to the accumulation of error counts of the watchdog timer. In clause 7,
If the charge/discharge test time required according to the time constants of the resistor and capacitor exceeds the disable time according to the error count accumulation of the watchdog timer, the charge voltage value is the voltage before charging is completed, and the discharge voltage value is A method of inspecting an input circuit of an electronic control device, characterized in that the voltage is before completion of discharge. In clause 7,
If the charge/discharge test time required according to the time constants of the resistor and the capacitor does not exceed the disable time according to the error count accumulation of the watchdog timer, the charge voltage value is the charging completed voltage, and the discharge voltage value is A method of inspecting an input circuit of an electronic control device, characterized in that the voltage is completely discharged. In clause 7,
An input circuit inspection method for an electronic control device, further comprising the step of the external reading device determining whether the input circuit is normal based on the difference between the charging voltage value and the discharging voltage value.

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