JPH113106A - Control constant reloading system for electronic control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high-reliability communication concerning a reloading system for control constants stored in a non-volatile memory (EEPROM or flash memory) provided at an electronic control unit(ECU) such as a traveling controller for vehicle. SOLUTION: A control line 7 is provided for transmitting a control signal for communication mode switch from an external device 2 to an ECU 1 in order to reload the control constant temporarily stored in the EEPROM inside the ECU 1 and when this control signal for communication mode switch shows a control constant reloading mode, the control constant in the EEPROM inside the ECU 1 can be reloaded by the external device 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for rewriting control constants stored in a non-volatile memory (EEPROM, flash memory) provided in, for example, an electronic control unit (ECU) of a vehicle drive control device. is there.

[0002]

2. Description of the Related Art FIG.
1 shows a configuration of a conventional electronic system device having a flash memory rewriting function shown in Japanese Patent Application Laid-Open Publication No. H11-209,036. In the figure, a microcomputer 21 built in a camera body 20 as an electronic system device is connected to a personal computer 25 as an external rewriting device via an external communication connector 24 of a serial line. A flash memory 22, a CPU (Central Processing Unit) 3, and a serial communication interface circuit 4 are provided to a microcomputer 21 in the camera body 20 via a bus 23, and are connected to each other so as to be mutually accessible. The CPU 3 performs predetermined control relating to transmission and reception of signal data, and plays a role of loading a program stored in advance in the flash memory 22 into a main storage area in the CPU 3 and executing the program. This flash memory 22 is divided into a plurality of blocks,
The contents can be erased and rewritten for each block.

Next, a communication operation between the electronic system device and an external device will be described. The conventional rewriting method is characterized in that control information is changed by writing data uploaded from an externally connected personal computer 25 using serial communication means to a specific block of the flash memory 22.

[0004]

Since the conventional electronic system device is configured as described above, the communication purpose between the electronic system device and the external device is used as a RAM monitor of control information other than rewriting of memory information. When performing a failure diagnosis or the like, a special communication means is required.

When a serial communication line is shared with a plurality of electronic control units (ECUs), when another electronic control unit (ECU) is communicating,
It is necessary to execute a special communication procedure so as not to rewrite data by mistake.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has been made in consideration of a flash memory or an EEPROM.
An object is to realize highly reliable communication by switching between a mode for rewriting data in a rewritable nonvolatile memory such as M and a mode for executing reading of RAM data by external means other than communication. I have.

[0007]

A system for rewriting control constants of an electronic control unit according to the present invention comprises: a CPU for performing various operations to calculate and generate a transmission signal and encoding received data; An electronic control unit provided with a nonvolatile memory (EEPROM, flash memory) for storing, and control of the electronic control unit (RA in the CPU)
An external device for rewriting the control constants of the nonvolatile memory, and connecting the external device and the electronic control unit via a control communication line, and communicating from the external device to the electronic control unit. A control line for transmitting the mode switching control signal is provided, and when the communication mode switching control signal is in the control constant rewriting mode, the control constants of the nonvolatile memory in the electronic control unit can be rewritten by an external device. It is characterized by.

More specifically, a communication mode switching control signal is transmitted from an external device to an electronic control unit inside the electronic control unit.
It has an EPROM data rewriting mode and a RAM data reading mode in the CPU. The control signal input interface circuit of the electronic control unit identifies a switching control signal output from an external device, and its signal level, signal frequency, or signal Depending on the duty ratio of
Whether the request is for the EEPROM data rewrite mode or the RAM
The CPU can determine whether the request is the data read mode.

Further, the communication mode switching control signal has a multi-level signal level, and the control constants of the nonvolatile memories in the plurality of electronic control units can be rewritten according to each level.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a control constant rewriting system of an electronic control unit according to a first embodiment, and a serial communication line between an external device (such as a personal computer) for rewriting the control constant and an electronic control unit (ECU). And connection diagrams of control lines.

In FIG. 1, the control constant rewriting system of the electronic control unit stores, for example, an electronic control unit (ECU) 1 for vehicle traveling control and control constants of the electronic control unit (ECU) 1. EEPROM
An external device (such as a personal computer) having a communication function for performing data rewriting and RAM data reading
2 The electronic control unit (ECU) 1 has a built-in one-chip CPU 3 as a central processing unit,
The CPU 3 performs various calculations to make the electronic control unit (ECU) 1 function, generates a transmission signal, and generates a signal for transmission.
It also plays the role of digitally encoding the received data.
The CPU 3 includes a transmission port (TX port), a reception port (RX port), and an input port (PIO port) for a communication mode switching control signal.
R storing a program for executing control and communication
OM and RA for temporarily storing control information and calculation information
M and an EEPROM for storing control constants are incorporated.

A serial communication interface circuit 4 and a control signal input interface circuit 5 are connected between the CPU 3 and the external device 2, and the serial communication interface circuit 4 communicates between the external device 2 and the electronic control unit (ECU) 1. The control signal input interface circuit 5 serves to match the electric signal level when performing the control.
It serves to convert the input signal level of U3. The serial communication line 6 is connected to the external device 2 and an electronic control unit (EC
U) Transmit serial communication information when serial communication is performed between 1. The control line 7 transmits a control signal for switching the communication mode from the external device 2. The GND line 8 serves as a reference signal when a signal is exchanged between the external device 2 and the electronic control unit (ECU) 1.

The electronic control unit (ECU) 1 has a built-in power supply circuit 9 for generating a constant voltage required for driving the device 1, and is connected to a battery. The CPU 3 of the electronic control unit (ECU) 1
, A control input interface circuit 10 and a control output interface circuit 11 are connected, and the control input interface circuit 10 transmits an electric signal obtained from various sensors and switch information as input information when the ECU 1 performs travel control or the like to the CPU 3. The control output interface circuit 11 converts an output signal for driving various actuators, which is a calculation result of the traveling control or the like, by the ECU 1 into an actuator drive signal level.

Next, the details of the communication operation of the control constant rewriting system of the electronic control unit according to the first embodiment will be described with reference to the circuit block diagram of FIG. 2 and the communication data time series diagram of FIG.

The external device 2 is an electronic control unit (ECU)
1 is fixed to 5 V inside the control signal input interface circuit 5 of the electronic control unit (ECU) 1 and is not connected to the EE.
The PROM data rewrite mode is disabled and set to the RAM monitor mode. When the external device 2 is connected to the electronic control unit (ECU) 1 and the external device 2 sets the control output signal to 0 V, the input signal of the PIO port of the CPU 3 inside the electronic control unit (ECU) 1 becomes 0 V, and the EEPROM data is The rewrite mode is set.

Thereafter, using a fixed communication speed determined in advance between the external device 2 and the electronic control unit (ECU) 1, data A: 1 is transmitted from the TX port of the external device 2.
When 00 is transmitted to the electronic control unit (ECU) 1, the data A: 100 is written to a predetermined address of the EEPROM in the CPU 3, and the executed signal ACK is output.
(1): 101 is transmitted to the external device 2. In this way, the CPU inside the electronic control unit (ECU) 1 continues.
3 receives the data B: 102 from the external device 2, similarly writes the data B: 102 to a predetermined address of the EEPROM, and executes the executed signal ACK (2):
103 is transmitted to the external device 2. After that, the PIO port input of the CPU 3 of the electronic control unit (ECU) 1
The EEPROM data rewriting mode is continued until the state is reached.

The control signal output of the external device 2 is 5 V
When the state is reached, the PIO port input of the CPU 3 of the electronic control unit (ECU) 1 becomes 5 V, and the state is the RAM data read mode. In this state, when an address (1): 104 is transmitted from the TX port of the external device 2 to the electronic control unit (ECU) 1, the CPU 3
Internal RAM address (1): Data corresponding to 104
(1): 105 is transmitted to the external device 2. When the CPU 3 in the ECU 1 receives the address (2): 106 from the external device 2 in this manner, similarly, the data corresponding to the address (2): 106 in the RAM in the CPU 3
(2): 107 is transmitted to the external device 2.

By proceeding with the above communication procedure, it is possible to reliably switch between the EEPROM data rewriting mode and the RAM data reading mode, and erroneous data rewriting due to abnormal communication data can be reliably prevented.

Embodiment 2 In the first embodiment, a case has been described in which two digital signal levels of 0 V and 5 V are used as the control output signal to switch between the EEPROM data rewriting mode and the RAM data reading mode, but as shown in FIG. By making the control signal input interface circuit an analog input circuit, any threshold value can be determined, and a plurality of electronic control units (ECUs) can be connected to the same serial communication line of an external device.
Is connected, the ECU to be executed in the EEPROM data rewriting mode can be designated by changing the voltage value of the control signal.

FIG. 4 is a block diagram showing a control constant rewriting system for an electronic control unit according to a second embodiment of the present invention. And a plurality of electronic control units (ECUs) 40, 42, 43
The control signal output interface 12 of the external device 30 includes a communication connector 46 and a control line 7.
Via a plurality of electronic control units (ECUs) 4
0, 42, and 43 are connected to the control communication interface circuit 5. Reference numerals 41, 43, and 45 denote CPUs incorporated in electronic control units (ECUs) 40, 42, and 43, respectively.

Next, the communication operation of the control constant rewriting system of the electronic control unit according to the second embodiment will be described in detail with reference to the time series diagram of FIG.

C in the electronic control unit (ECU) 40
The EEPROM data rewrite mode determination voltage input to the port AD0 of the PU 41 is set to 0 V or more and less than 1.25 V,
The EEPROM data rewrite mode determination voltage input to the port AD0 of the CPU 43 in the electronic control unit (ECU) 42 is set to 1.25 V or more and less than 2.5 V, and the port AD of the CPU 45 in the electronic control unit (ECU) 44 is set.
The EEPROM data rewrite mode determination voltage input to 0 is set to 2.5 V or more and less than 3.75 V. The RAM data read mode determination voltage of the electronic control units (ECUs) 40, 42, and 44 is set to 3.75 V or more.

First, when the external device 30 outputs the control output signal 206 and transmits data C: 200, E
RX of CPU41,43,45 of CU40,42,44
Although data C: 200 is input to the port, the external device 3
The CPU 41 inside the ECU 40 recognizes that the control output signal 206 of 0 is 0.625 V and is within the EEPROM rewrite mode determination voltage of the ECU 40, and the data C: 200 is stored in the EEPROM 41 inside the CPU 41 of the ECU 40.
The executed signal ACK40: 201 written at a predetermined address of the PROM is transmitted from the ECU 40 to the external device 30.
Reply to

Thereafter, when the external device 30 outputs the control output signal 207 and transmits the data D: 202,
R of the CPUs 41, 43, 45 of the ECUs 40, 42, 44
The data D: 202 is input to the X port. The CPU 43 inside the ECU 42 recognizes that the control output signal 207 of the external device 30 is 1.875 V and is within the EEPROM rewrite mode determination voltage of the ECU 42, : 202 is the EE inside the CPU 43 of the ECU 42
The executed signal ACK42: 203 written to a predetermined address of the PROM is transmitted from the ECU 42 to the external device 30.
Reply to

When the external device 30 outputs the control output signal 208 and transmits the data E: 204,
RX of CPU41,43,45 of CU40,42,44
The data E: 204 is input to the port, but the control output signal 208 is 3.125V and the ECU 44 determines that the voltage is within the EEPROM rewrite mode determination voltage of the ECU 44.
44, the data E: 204 is recognized as E.
The executed signal ACK44 is written to a predetermined address of the EEPROM in the CPU 45 of the CU 44 and executed.
205 is returned from the ECU 44 to the external device 30.

Further, when the external device 30 outputs the control output signal 209, the control output signal 209
Is 5V, so that ECUs 40, 42 and 44 are all EE
The mode shifts from the PROM data rewrite mode to the RAM data read mode.

By executing the above procedure, EEPROM data rewriting can be reliably executed for a plurality of electronic control units (ECUs) connected to the same serial communication line 6 individually.

Embodiment 3 In the above embodiment, EE
The switching of the communication mode between the PROM data rewriting mode and the RAM data reading mode is determined based on the voltage level of the control signal. However, a duty signal having a constant frequency may be used as the control signal for switching the communication mode. Due to the difference in the length of the LOW level time or HIGH level time of the duty signal,
It is possible to switch the EPROM data rewrite target mode.

Other Embodiments In the above embodiment, various operations are performed to make the electronic control unit (ECU) function, a signal for transmission is calculated and generated, and a transmission port (TX port), a reception port, and a reception port are digitally coded. Port (RX port), input port for communication mode switching control signal, and RO
The M, RAM, and EEPROM have been described as having a built-in type. However, the ROM, RAM, and EEPROM may be connected to an externally used CPU, or may be a ROM, an R,
The present invention can be similarly applied to an electronic control unit (ECU) having a built-in AM and an EEPROM connected to an external device and having a CPU.

[0030]

As described above, according to the present invention, the nonvolatile memory (EEPR) inside the electronic control unit (ECU) is provided.
By switching between the OM) data rewriting mode and the general control (RAM data reading) mode using control signals other than the general control communication (serial communication), highly reliable serial communication control can be performed. .

[Brief description of the drawings]

FIG. 1 shows an external device and an external device according to a first embodiment of the present invention.
FIG. 3 is a connection diagram of serial communication lines and control lines between CUs.

FIG. 2 shows connection details of a serial communication interface circuit of an external device and a serial communication interface circuit of an ECU according to Embodiment 1 of the present invention, and connection details of a control signal output interface of the external device and a control signal input interface of the ECU. FIG.

FIG. 3 is an EEPROM according to the first embodiment of the present invention;
FIG. 9 is a time series diagram of communication data when performing data rewriting and RAM data reading.

FIG. 4 shows connection details of a serial communication interface circuit of an external device and a serial communication interface circuit of a plurality of ECUs, a control signal output interface of an external device, and a plurality of ECs according to Embodiment 2 of the present invention;
FIG. 9 is a connection diagram showing connection details of a control signal input interface of U.

FIG. 5 is an EEPROM according to a second embodiment of the present invention;
FIG. 9 is a time series diagram of communication data when performing data rewriting and RAM data reading.

FIG. 6 is a connection diagram of a conventional data rewriting communication system.

[Explanation of symbols]

1 electronic control unit (ECU), 2 external device, 3
CPU, 4 serial communication interface circuit, 5
Control signal input interface circuit, 6 serial communication line, 7 control line, 8 GND line for communication, 9 power supply circuit, 10 control input interface circuit, 11 control output interface circuit,
12 control signal output interface circuit, 3
0 external device, 40, 42, 44 ECU, 41, 4
3,45 CPU, 46 Communication connector.

Claims (3)

[Claims] 1. A system for rewriting control constants of an electronic control unit, comprising: a central processing unit (CPU) having a built-in nonvolatile memory for storing at least the control constants; An external device for performing control or rewriting of control constants, a communication line for general control connecting the external device and the electronic control unit, and a communication mode switching control signal from the external device to the electronic control unit. And a control line for transmitting, wherein when the communication mode switching control signal is in a control constant rewriting mode, the control constant of the nonvolatile memory in the electronic control unit can be rewritten by the external device. Control constant rewriting system for electronic control unit. 2. The electronic control unit according to claim 1, wherein the control signal for switching the communication mode can be determined to be a control constant rewriting mode or a general control mode by a signal level, a signal frequency, or a signal duty ratio. Control constant rewriting system. 3. The communication mode switching control signal has a multi-step signal level, and a control constant of a nonvolatile memory in a plurality of electronic control units can be rewritten according to each step. 3. The control constant rewriting system for an electronic control unit according to claim 1 or 2.