JP3672755B2 - Control program rewriting system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control program rewriting system for rewriting a control program stored in a flash ROM of an electronic control device for an automobile mounted on a vehicle.
[0002]
[Prior art]
FIG. 5 shows a memory rewriting system of an electronic control device having a conventional flash ROM rewriting function disclosed in, for example, Japanese Patent Laid-Open No. 9-134307. In the figure, 20 is an engine control unit (ECU), 40 is a memory rewrite device for a flash ROM provided in the engine control device 20, and 420 is a connection for connecting the engine control device 20 and the memory rewrite device 40 via a communication line 440. Connector. A conventional memory rewriting system 60 includes an engine control device 20 and a memory rewriting device 40.
[0003]
The engine control device 20 calculates the optimum control amount for the engine based on the signals from the input device 80 and the input device 80 that input signals from various sensors that output signals according to the operating state of the engine, and the calculation result CPU 100 for outputting a control signal according to the above, a control signal from CPU 100, an output circuit 120 for driving an actuator such as an injector or an igniter attached to the engine, and a control program and control data necessary for CPU 100 to control the engine A flash ROM 140 for storing data, a ROM 160 for storing programs necessary for the CPU 100 to operate, a RAM 180 for temporarily storing calculation results of the CPU 100, and a communication device 200 for performing serial data communication with the memory rewriting device 40. Has
[0004]
On the other hand, the memory rewriting device 40 includes a CPU 220 for causing the engine control device 20 to rewrite the flash ROM 140, a ROM 240 for storing programs necessary for the operation of the CPU 220, a RAM 260 for temporarily storing calculation results of the CPU 220, and the CPU 220. Is a communication circuit 280 for performing serial data communication with the engine control device 20, an input device 300 for an operator to input various instructions to the memory rewriting device 40, and a display device for displaying various messages. 320, a storage device 340 for storing a new control program and control data prepared for writing in the flash ROM 140 of the engine control device 20, and an interface 360 for connecting the CPU 220 to the input device 300, the display device 320, and the storage device 340. Preparation To have.
[0005]
Next, the operation will be described. Before the memory rewrite device 40 transmits the control program prepared in the storage device 340 by the operator to the flash ROM 140 of the engine control device 20 via the communication line 440, the memory rewrite device 40 identifies the control target that matches the control program. The code is transmitted to the engine control device 20.
[0006]
The CPU 100 of the engine control control device 20 executes a rewriting process for rewriting the flash ROM 140 only when the identification code from the memory rewriting device 40 and the identification code indicating its own control object match.
[0007]
[Problems to be solved by the invention]
Since the conventional device is configured as described above, the memory rewriting device and the engine control device require one-to-one command response communication, and rewriting is performed when multiple ECUs are connected on the same communication line. The response was difficult.
[0008]
The present invention has been made to solve the above-described problems. When a plurality of ECUs are connected to the same communication line and the same rewrite power supply line, a flash built in a specific ECU is provided. Rewrite the control program stored in ROM, , E The present invention relates to a control program rewriting system for protecting a rewrite control CPU built in an ECU when a rewrite power supply voltage is applied to a CU.
[0009]
[Means for Solving the Problems]
A control program rewriting system according to a first aspect of the present invention is a plurality of CPU-equipped electronic control devices connected to the same power supply line and the same communication line, and connected to the power supply line and the communication line. A power supply for rewriting the program to each of the electronic control devices for automobiles through the power supply line, and an external device for communicating a rewrite control signal through the communication line. One of them prohibits the input of the program rewriting power supply from the external device based on the detection that the rewriting request signal is input from the external device through the communication line or based on its own control operation. , Having rewrite power input control means to allow In addition, the external device has a program forcible rewriting means for operating the rewriting power input control means of the automobile electronic control device and inputting the power for program rewriting when there is no response signal in the automotive electronic control device. Is.
[0010]
The rewrite power supply input control means in the control program rewrite system according to the invention of claim 2 prohibits the input of the program rewrite power from the external device during the control operation of each automobile electronic control device.
[0013]
Claim 3 The external device in the control program rewriting system according to the invention determines that the program is abnormal when an acknowledgment to the rewrite request signal has not been received even after a predetermined time has elapsed, and recognizes the ON signal of the program forced rewriting means, It has an abnormality determination means for operating the rewrite power supply input control means.
[0014]
Claim 4 In the control program rewriting system according to the invention, the external device displays a display indicating that the rewriting is impossible when the erasing end signal for the erasing request of the existing program transmitted to the electronic control unit for an automobile is not received even after a predetermined time has elapsed. It has a means.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a control program rewriting system according to the present embodiment.
In FIG. 1, reference numeral 1 denotes an automotive electronic control device (hereinafter referred to as an ECU), 2 denotes an external device, and the external device 2 rewrites a control program built in the flash ROM of the ECU 1. Control code, a communication function for transmitting / receiving rewrite data, a flash ROM erasing function, and a rewrite power supply circuit.
[0016]
The ECU 1 has a built-in one-chip CPU 11, in which a flash ROM for storing a program for executing vehicle control and communication with the external device 2, a flash ROM rewriting communication program, and a flash ROM rewriting execution are stored. Boot ROM with built-in program, RAM for temporarily storing control information and calculation information, input port PIN for inputting control signals, output port POUT for outputting control signals based on calculation results, rewrite permission Signal output port PCS, input port VP of the power supply for program rewriting with built-in flash ROM, reception port RX and transmission port TX for executing communication between external device 2 and ECU 1, whether the operation program is flash ROM or built-in boot ROM Built-in input port MODE for selecting To have.
[0017]
Further, the ECU 1 has a built-in rewrite power supply input circuit 12, which controls the supply / cutoff of the rewrite power supplied from the external device 2, and a signal for starting the boot ROM built-in program in the CPU 11. Is generated. The rewrite power supply input circuit 12 is turned on / off according to the input logic level of the input port CS to supply / shut off the rewrite power supply voltage to the CPU 11, the ECU power supply detection delay output circuit 122, and the CPU 11. An AND gate circuit 123 that performs a logical product of the rewrite permission signal and the signal of the ECU power supply detection delay output circuit 122 to generate a control signal of the switch circuit 121. When the rewrite power supply voltage is supplied to the VP port of the CPU 11, the boot ROM A mono multivibrator 124 that generates a reset pulse signal for a predetermined period to start the built-in program, a rewrite power supply voltage is supplied to the port VP of the CPU 11 and a signal to the port MODE at the same time, and a rising signal of the mono multivibrator 124 CPU inside by synchronizing with Outputs the logical product of the power-on reset signal from the interface circuit 125 and the power supply circuit 14 for starting the boot ROM built-in program and the reset signal from the mono multivibrator 124, and supplies the signal to the port RST of the CPU 11 An AND gate circuit 126 is provided. Reference numeral 127 denotes a pull-up resistor of the power supply VCC connected to the rewrite permission signal output port PCS.
[0018]
Further, the ECU 1 is necessary for operating the ECU 1 from the communication interface circuit 13 for matching the electric signal level when the external device 2 and the ECU 1 communicate with each other, and the power supply voltage supplied from the battery 30 mounted on the vehicle. A power supply circuit 14 that generates a constant voltage, and a control input interface circuit 15 for converting an electrical signal obtained from various sensors and switch information as input information into an input signal level of the CPU when the ECU 1 performs control. Is provided with a control output interface circuit 16 for converting an output signal for driving various actuators, which is a calculation result of control, to an actuator drive signal level.
[0019]
The external device 2 has a built-in CPU 21. In the CPU 21, a ROM that stores a communication program necessary for flash ROM rewriting support of the CPU 11 built in the ECU 1 and a RAM that temporarily stores control information and calculation information are stored. And an output port for controlling the rewrite power supply circuit 23, an external switch signal input port, a reception port RX and a transmission port TX for executing communication between the external device 2 and the ECU 1, and transfer to the flash ROM to be rewritten Connection port AX. DX is built-in.
[0020]
The external device 2 includes a communication interface circuit 22 for matching the electrical signal level when the external device 2 communicates with the ECU 1, and a rewrite power supply circuit whose output is controlled by the CPU 21 and supplied to the CPU 11 inside the ECU 1. 23, a ROM 24 having a program code written in a flash ROM built in the CPU 11 in the ECU 1 is provided.
[0021]
The external switches 25a and 25b provided in the CPU 21 indicate external switches for permitting the rewriting operation of the external device. Specifically, the external switch 25a is for starting standard rewriting, and the external switch 25b is forcibly starting rewriting. It is for. The forced rewriting is used when forcibly rewriting when the program of the CPU 11 in the ECU 1 is in an abnormal state.
[0022]
The pilot lamps 26a and 26b provided in the CPU 21 are pilot lamps indicating the end result of rewriting. Specifically, the pilot lamp 26a is turned on when rewriting is normally completed, and the pilot lamp 26b is turned on when rewriting is impossible.
The power supply circuit 27 built in the external device 2 is supplied with a voltage from a battery 30 mounted on the vehicle, and generates a constant voltage necessary for operating the external device 2.
[0023]
A line connected between the external device 2 and the ECU 1 through the connection connector 10 indicates the communication line 3 for performing communication between the external device 2 and the ECU 1 through the communication interface circuits 22 and 13. A line connected between the ECU 2 and the ECU 1 indicates a power supply line 4 for supplying rewrite power to the CPU 11 from the rewrite power supply circuit 23 of the external device 2 through the rewrite power input circuit 12 inside the ECU 1.
[0024]
A line 8 drawn from the external device 2 through the connection connector 10 to the ECU 1 side supplies power from the battery 30 to the power input terminal of the power circuit 27 built in the external device 2 in order to operate the external device 2. 8. The power line 8 is connected to the positive side of the battery 30 whose negative side is grounded, and the positive side is connected to the power input terminal of the power circuit 14 built in the ECU 1 through the IG (ignition) switch 5 and the power line 6. The
[0025]
The IG switch 5 is a switch used to supply / shut off power to the ECU 1, and the ECU 1 can be controlled only when the IG switch 5 is ON. Reference numeral 7 denotes a GND line of the ECU 1. Reference numeral 9 denotes a GND line of the external device 2. The GND line 9 of the external device 2 is at the same potential as the GND line 7 of the ECU 1.
[0026]
Next, a detailed description of the operation of the present embodiment will be described with reference to FIGS.
FIG. 2 shows a procedure for executing rewriting of the built-in program in the flash ROM 11 built in the CUP 11, and FIG. 3 shows a time series diagram at the time of rewriting execution.
[0027]
First, the operation of the ECU 1 will be described.
In FIG. 3, first, when the IG switch 5 is turned on, the power supply circuit 14 is activated, converts the battery voltage into a stabilization voltage necessary for the operation of the internal circuit of the ECU 1, and outputs the stabilization voltage from the VCC output terminal.
[0028]
Thereafter, after a period T1, a logic 1 signal is output from the port RST of the power supply circuit 14, and a logic 1 signal is also output from the port RSTO of the mono multivibrator 124, whereby the output signal of the gate 126 is changed from a logic 0 to a logic 1 signal. When the input signal of the port RST of the CPU 11 changes from logic 0 to logic 1, the flash ROM built-in program in the CPU 11 is activated.
[0029]
Since a logic 1 signal is supplied to the port PCS for outputting the rewrite permission signal of the CPU 11 by the pull-up resistor 127 connected to the power supply VCC, until a logic 0 output is performed from the port PCS by a program operation, A logic 1 signal is supplied to port A of gate 123.
[0030]
If the program is in an abnormal state, the output from the power detection delay output circuit 122 becomes logic 1 after the period T3, so that the logical product result output C of the gate 123 becomes 1, and the CS input of the switch circuit 121 becomes As a result of the logic 1, the internal switch of the switch circuit 121 is turned ON, and the energization permission state of the rewrite power source is set in the ECU 1.
Therefore, even if the internal program of the CPU 11 is in an abnormal state, the flash ROM built-in program can be rewritten.
[0031]
In step S51 of FIG. 2, it is determined whether the CPU 11 built-in program is normal. If it is normal, the process proceeds to step S52. In step S52, initial setting of CPU 11 internal registers and RAM data necessary for executing the control is executed.
[0032]
Next, in step S53, a logic 0 is output from the port 11 for outputting the rewrite permission signal of the CPU 11. Step S53 shows the output state after the period T2 in FIG. 3, and the power supply detection delay output after the period T3. The logic 1 output from the circuit 122 is supplied to the port B of the gate 123. Since the logic 0 signal has already been supplied to the port A, the logical product output result C of the gate 123 becomes 0, and the switch circuit 121. When the CS input becomes logic 0, the internal switch of the switch circuit 121 is turned OFF, and the ECU 1 is in a state in which energization of the rewrite power supply is prohibited.
[0033]
Therefore, until the rewrite request signal is sent to the ECU 1 using the communication means in the future, the rewrite prohibition state is set, and the flash ROM built-in program in the ECU 1 is prevented from being rewritten by mistake.
[0034]
Next, in step S54, input information necessary for executing the control is fetched from the internal port PIN of the CPU 11 and stored in the built-in RAM.
Next, based on the input information stored in the built-in RAM in step S55, various arithmetic processes for realizing control are executed.
Next, in step S56, the various calculation results obtained in step S55 are output to the CPU 11 internal port POUT.
Next, in step S57, it is determined whether or not the flash ROM built-in program rewrite request is received from the external device 2 using the communication means. If there is no rewrite request, the process returns to step S53, and the above steps S53 to S56 are repeated. If there is a rewrite request, the process proceeds to step S58.
Next, in step S58, an affirmative response to the rewrite request is returned to the external device 2 using the communication means.
Next, in step S59, a control stop process is executed to enter a state of waiting for rewriting of the program built in the flash ROM.
Next, in step S60, the logic 11 is output from the port PCS for outputting the rewrite permission signal of the CPU 11, and the output from the power detection delay output circuit 122 is logic 1, so that the logical product result output C of the gate 123 is output. When the CS input of the switch circuit 121 becomes logic 1, the internal switch of the switch circuit 121 is turned ON, and the power supply permission state of the rewrite power supply is set in the ECU 1.
[0035]
Next, in step S61, the program enters a standby state for starting a program stored in the boot ROM in the CPU 11 (hereinafter referred to as a boot program).
The boot program is started when the input logic of the port MODE of the CPU 11 is logic 1, that is, when the input logic of the port RST is changed from 0 to 1 in a state where the rewrite power from the external device 2 is supplied. . When the rewrite power is supplied from the external device 2 while the internal switch of the switch circuit 121 is ON, both the ports MODE and VP of the CPU 11 become logic 1 and at the same time a logic 1 signal is also supplied to the mono multivibrator 124. A transient pulse signal indicating a change of logic 1 → logic 0 → logic 1 is output from the vibrator 124, and this pulse signal is supplied to the port RST of the CPU 11.
Therefore, the boot program in the CPU 11 is started by this procedure.
[0036]
Next, in step S63, the flash ROM built-in program erasure request wait state is entered, and when an erasure request is received using the communication means, the process proceeds to step S64.
Next, in step S64, the CPU 11 internal boot program executes erasure of the flash ROM built-in program. The power for erasing and rewriting the program uses the rewrite power supplied from the port VP. Since the boot program in the CPU 11 is not stored in the flash ROM, the boot program is not damaged by execution of erasure.
Next, in step S65, it is determined whether all program areas of the flash ROM have been erased. If the erasure is completed, the process proceeds to step S66.
Next, in step S66, the fact that the erase of the program stored in the flash ROM has been completed is sent back to the external device 2 as the rewriting device using the communication means.
[0037]
Next, in step S67, the program is written into the flash ROM. As the rewrite data, data transmitted from the rewrite device is received by the communication means, and written sequentially. In step S68, it is determined whether or not the reception of the data for rewriting the flash ROM has been completed. If it has not been completed, step S67 is executed again. In step S68, when a rewrite end signal is received, the process proceeds to step S69.
Next, a response to the rewrite end signal is transmitted in step S69, and the process proceeds to step S70. In step S70, in order to wait for the flash ROM built-in program to be restarted, a reset input wait state is entered. When the reset input is executed, the process returns to step S50 again.
[0038]
Next, the operation of the external device 2 will be described.
After the external device 2 is activated, in order to perform standard rewriting in step S1, when the switch 25a is turned on and the CPU 21 in the external device 2 recognizes the ON signal, in step S2, the flash ROM rewrite request signal is sent to the communication means. Used to transmit to the ECU 1.
[0039]
Next, in step S3, the ECU 1 waits for an affirmative response to the flash ROM rewrite request signal. If an affirmative response is received, the process proceeds to step S4, where a logic 1 is output to the port POUT of the CPU 21, and the rewrite power supply output to the ECU 1 is turned ON.
[0040]
If an affirmative response is not received in step S3, the reception waiting time-out is determined in step S12, and if not, the process returns to step S3. If the time expires, the process proceeds to step S13, and a non-rewritable display is displayed and output to the pilot lamp 26b in step S13.
[0041]
In order to perform forced rewriting in step S14, when the switch 25b is turned on and the CPU 21 in the external device 2 recognizes the ON signal, the process proceeds to step S15, where a logic 1 is output to the port POUT of the CPU 21, and Turn on the rewrite power supply output.
Next, after a logic 1 output from the port POUT of the CPU 21, in step S5, a request for deleting the flash ROM built-in program is transmitted to the ECU 1 using the communication means.
Next, in step S6, the ECU 1 waits for an erase end response for the program stored in the flash ROM from the ECU 1. If an erase end response is received, the process proceeds to step S7, and if not received, the process proceeds to step S16. In step S16, it is determined whether or not the reception waiting time has expired. If not, the process returns to step S6. If the time expires, the process proceeds to step S17, and a non-rewritable display is displayed and output to the pilot lamp 26b in step S17.
[0042]
Next, in step S7, the flash ROM built-in program data is transmitted using the communication means. In step S8, it is determined whether or not all data transmission is completed. Send program data. When all the data transmission is completed, the process proceeds to step S9.
Next, in step S9, a flash ROM built-in program rewrite end signal is transmitted to the ECU 1 using communication means.
Next, in step S10, it waits for reception of a rewrite end response from the ECU 1 in response to a rewrite end signal of the external device 2. When a rewrite response is received, the process proceeds to step S11. In step S11, a rewrite completion display is displayed on the pilot lamp 26a.
[0043]
Embodiment 2. FIG.
In the first embodiment, the ECU 1 turns on / off the switch circuit 121 using the logical product of the delay output of the power supply voltage detection delay output circuit 122 and the rewrite permission signal. By performing the / OFF control by control of a built-in CPU different from the CPU 11, the same effects as those of the first embodiment can be obtained and the circuit configuration can be simplified.
[0044]
Hereinafter, this embodiment will be described with reference to FIG. 4 with respect to changes from the first embodiment. In the figure, reference numeral 130 denotes a CPU 130 including the functions of the power supply detection delay output circuit 122, the gate 123, and the mono multivibrator 124 in the first embodiment.
[0045]
Next, details of the operation of the present embodiment will be described.
After the power supply VCC in the ECU 1 rises, the CPU 130 outputs a logic 1 signal from the port RSTO. If the input signal of the port CSI continues to be logic 1 even after the period T3 in FIG. 3 is exceeded, the CPU 130 determines that the CPU 11 is in an abnormal state, outputs a signal of logic 1 to the port CSO, and When the input logic becomes logic 1, the switch in the switch circuit 121 is turned on.
[0046]
Therefore, the rewrite power supply voltage can be supplied from the external device 2 to the CPU 11 in the ECU 1. Next, when the rewrite power supply voltage is supplied from the external device 2 and the output signal from the interface circuit 125 becomes logic 1, a logic 1 signal is supplied to the port VPD of the CPU 130. A pulse signal for a certain period, that is, logic 1 → logic 0 → logic 1 is output, and the internal operation program of the CPU 11 is switched to the boot program.
[0047]
Hereinafter, the rewriting operation is the same as that after step S63 in FIG.
When the CPU 11 is operating normally, after the period T2 in FIG. 3, a signal of logic 0 is output from the port PCS of the CPU 11, and the input signal of the port CSI of the CPU 130 becomes logic 0, so that the CPU 130 Output a logic 0 signal to CSO. Since a logic 0 signal is input to the port CS of the switch circuit 121, the switch in the switch circuit 121 is turned off, and the rewrite power supply voltage from the external device 2 is not supplied to the CPU 11.
[0048]
When a logic 1 signal is output from the port PCS of the CPU 11, a logic 0 signal is supplied to the port CSI of the CPU 130, and the CPU 130 outputs a logic 1 signal to the port CSO, and the input logic of the port CS of the switch circuit 121. Becomes logic 1, and the switch in the switch circuit 121 is turned on.
[0049]
Therefore, the rewrite power supply voltage can be supplied from the external device 2 to the CPU 11 in the ECU 1. Next, when the rewrite power supply voltage is supplied from the external device 2 and the output signal from the interface circuit 125 becomes logic 1, a logic 1 signal is supplied to the port VPD of the CPU 130. A pulse signal for a certain period, that is, logic 1 → logic 0 → logic 1 is output, and the internal operation program of the CPU 11 is switched to the boot program.
Hereinafter, the rewriting operation is the same as that after step S63 in FIG.
[0050]
Embodiment 3 FIG.
In each of the above-described embodiments, it is necessary to supply a rewriting power source from the outside for rewriting the flash ROM built-in program. However, a CPU that does not require a separate power source for the rewriting power source is the CPU 11 of the first embodiment. It is possible to obtain the same effect as that of the above embodiment only by deleting the connection line to the port VP.
[0051]
【The invention's effect】
According to the first aspect of the present invention, a plurality of CPU-equipped automotive electronic control devices respectively connected to the same power supply line and the same communication line, and the power supply line connected to the power supply line and the communication line. A power supply for program rewriting to each of the electronic control devices for automobiles, and an external device for communicating a rewrite control signal through the communication line, and a specific one of the plurality of electronic control devices for automobiles is Rewriting that prohibits / permits input of a power supply for program rewriting from the external device based on the detection that a rewrite request signal is input from the external device through the communication line or based on its own control operation Has power input control means In addition, the external device has a program forcible rewriting means for operating the rewriting power input control means of the automobile electronic control device and inputting the power for program rewriting when there is no response signal in the automotive electronic control device. Therefore, there is an effect that the CPU can be protected even when the rewrite power supply voltage is sent from the external device to the automobile electronic control device.
[0052]
According to the second aspect of the present invention, the rewrite power input control means prohibits the input of the program rewrite power from the external device during the control operation of each automobile electronic control device, so that the control program is protected. There is an effect that can be.
[0055]
Claim 3 According to the invention, when the external device does not receive an acknowledgment for the rewrite request signal even after a lapse of a predetermined time, it is determined that the program is abnormal, and when the ON signal of the program forced rewrite means is recognized, the rewrite power input control is performed. Since the vehicle electronic control apparatus does not need to monitor the program abnormality, the software load can be reduced because the abnormality determining means for operating the means is provided.
[0056]
Claim 4 According to this invention, the external device has the display means for displaying the non-rewritable signal when the erasing end signal for the erasing request for the existing program transmitted to the electronic controller for the vehicle is not received even after a predetermined time. There is an effect that usability for the user is improved.
[Brief description of the drawings]
FIG. 1 shows a connection state of a communication line between an external device and an ECU according to Embodiment 1 of the present invention, and a block diagram of an ECU internal circuit.
FIG. 2 is a flowchart showing a rewrite procedure of a flash ROM built-in program in the ECU according to the embodiment of the present invention.
FIG. 3 shows a time series diagram of a rewriting procedure of a flash ROM built-in program in the ECU according to the embodiment of the present invention.
FIG. 4 shows a connection state of communication lines between an external device and an ECU according to another embodiment of the present invention, and a block diagram of an ECU internal circuit.
FIG. 5 shows a communication line connection state between a conventional memory rewriting device and an ECU, and an ECU internal circuit block diagram.
[Explanation of symbols]
1 ECU, 2 External device, 3 Communication line, 4 Rewrite power line, 5 IG switch, 6, 8 Power line, 11, 21, 130 CPU, 12 Rewrite power input circuit, 13, 22 Communication interface circuit, 23 Rewrite power supply Circuit, 26a, 26b Pilot lamp, 121 switch circuit, 122 power supply detection delay output circuit.

Claims (4)

A plurality of CPU-mounted electronic control devices connected to the same power supply line and the same communication line;
An external device connected to the power supply line and the communication line for supplying a program rewriting power to each of the automotive electronic control devices through the power supply line, and for communicating a rewrite control signal through the communication line;
The specific one of the plurality of automotive electronic control devices is based on detecting that a rewrite request signal is input from the external device through the communication line, or based on its own control operation. program input update-power from the prohibition, which has a rewrite power input control means for permitting,
The external device has program forcible rewriting means for operating the rewrite power input control means of the vehicle electronic control device and inputting the program rewrite power when there is no response signal in the vehicle electronic control device. Control program rewriting system. 2. The control program rewriting system according to claim 1, wherein the rewrite power supply input control unit prohibits input of a program rewrite power supply from the external device during a control operation of each automobile electronic control device. When the external device does not receive an acknowledgment to the rewrite request signal even after a predetermined time, it is determined that the program is abnormal, and when the ON signal of the program forced rewrite means is recognized, the rewrite power input control means is activated. The control program rewriting system according to claim 1, further comprising a determination unit . The external device according when even the erase end signal for the erasure request for an existing program that sent the automobile electronic control device a predetermined time has elapsed has not been received, characterized in that it comprises a display means for displaying a non-rewritable Item 8. The control program rewriting system according to Item 1 .

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