JP3494031B2 - Automotive electronic control unit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on- vehicle electronic control device having a data rewriting function for a rewritable nonvolatile memory.

[0002]

2. Description of the Related Art Conventionally, as a prior art document related to an on- vehicle electronic control device, one disclosed in Japanese Patent Application Laid-Open No. 10-47151 is known. This is a nonvolatile memory (EEPROM: Electrical Era) that can be rewritten in a serial communication module (serial interface).
sable Programmable ROM) and an input / output module (external communication device) are connected in parallel, and the control target is controlled by turning on / off the ignition switch for each operating period of the on- vehicle electronic control device. It is something to switch. That is, the data transfer / writing from the volatile memory (RAM) to the non-volatile memory (EEPROM) is set after the power supply to the vehicle-mounted electronic control unit is stopped, specifically, after the ignition switch is turned off. It is achieved by that.

[0003]

By the way, as described above, when writing to the nonvolatile memory (EEPROM) is started by turning off the ignition switch, power is supplied to the on- vehicle electronic control unit until the writing is completed. However, there is a problem that a waiting time until the power is actually cut off occurs, that is, extra time is spent.
Also, since the update data during normal control by the vehicle-mounted electronic control device is only reflected in the volatile memory (RAM),
In the meantime, if there is a momentary interruption of the power supply voltage or the like and it is reset, the update data is erased and is not reflected in the non-volatile memory (EEPROM).

The present invention has been made in order to solve such a problem, and the update data is reflected in the volatile memory during the normal control of the on- vehicle electronic control unit, so that the power supply voltage is interrupted during the control. Therefore, it is an object to provide an in- vehicle electronic control device that can reflect the updated data up to that point in the nonvolatile memory without spending extra time.

[0005]

According to the on- vehicle electronic control device of the present invention, the ignition switch is turned on.
During a certain period, when the microcomputer having the serial communication module does not communicate with the input / output module at each predetermined timing, the contents of the buffer for temporarily storing the transmission data to the rewritable nonvolatile memory are confirmed. When transmission data is stored, communication to the non-volatile memory is executed via the serial communication line. In this way, during the normal control of the vehicle-mounted electronic control unit, the transmission data, which is the update data, is written into the nonvolatile memory at any time by utilizing the idle time of communication with the input / output module, and thus the nonvolatile memory No extra time is spent in the writing process to the non-volatile memory, and the updated data up to that point is surely reflected in the nonvolatile memory even if the power supply voltage is interrupted.

According to the on-vehicle electronic control device of the present invention,
Input / output module and ignition on black computer
Communication is performed every predetermined time during which the switch is on.
By sending the update data at any time during normal control
By writing the data to the non-volatile memory,
Even if there is a momentary voltage interruption, the update data up to that point is non-volatile
Surely reflected in sex memory.

In the on- vehicle electronic control device of the third aspect , when it is confirmed by the microcomputer that the transmission data is stored in the buffer, the communication with the non-volatile memory is performed until all the transmission data are completed. Since it is continuously executed, the updated data during the normal control is surely reflected in the nonvolatile memory.

[0008] In-vehicle electronic control device according to claim 4, when it is confirmed that the transmission data in the buffer is stored in the microcomputer, communication is performed with the constant amount by nonvolatile memory of the transmission data Therefore, the updated data during the normal control is surely reflected in the nonvolatile memory.

[0009] In-vehicle electronic control device according to claim 5, the buffer contents are verified immediately after the completion of the communication with the input module by the microcomputer, an interrupt is generated when the transmission data in the buffer is stored As a result, the updated data during normal control is quickly reflected each time.

According to the on-vehicle electronic control unit of claim 6,
Microcomputer having serial communication module
Immediately after the communication with the I / O module is completed.
Temporarily send data to convertible non-volatile memory
The contents of the buffer to be stored are confirmed, and the transmission data is stored.
Non-volatile via serial communication line when
Communication to the memory is performed. Thus, in-vehicle electronic
Communication with the I / O module during normal control of the control unit
Immediately after the transmission is completed, the transmission data that is the update data
Power supply voltage is ensured by the sure writing process to volatile memory.
Even if there is a momentary interruption, the updated data up to that point is non-volatile.
Certainly reflected in Mori.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on Examples.

[0012] Figure 1 is a block diagram showing the overall construction of the embodiment of the internal combustion engine electronic control unit mounted in-vehicle electronic control device is applied a vehicle according to an embodiment of the present invention.

In FIG. 1, 10 is an electronic control unit for an internal combustion engine (hereinafter, simply referred to as "EC
U)), and the ECU 10 has various sensors (not shown) for detecting an operating state of the internal combustion engine, such as an engine speed signal NE from a crank angle sensor 1, a cooling water temperature signal THW from a water temperature sensor 2, and an air flow meter 3. Various sensor signals such as the intake air amount signal GN are input, and the power supply voltage + B from the battery power supply 4 is input via the IGSW (ignition switch) 5 and the main relay 6 arranged in parallel with the IGSW 5. . These various sensor signals and the like are input to the microcomputer 20 via the input interface circuit 11 in the ECU 10. Further, the power supply voltage + B from the battery power supply 4 is input to the constant voltage power supply circuit 12 in the ECU 10 via the IGSW 5 and the main relay 6, and the constant voltage power supply by the constant voltage power supply circuit 12 is input to the microcomputer 20. .

Further, the ECU 10 receives the knock signal KNK from the knock sensor 7 and the A / F signal AFVAL from the A / F (air-fuel ratio) sensor 8 via the input interface circuit 13 in the ECU 10 respectively. Judgment IC) 14, A / F-IC (A / F detection IC) 1
It is entered in 5. The input interface circuit 1
In 1 and 13, waveform shaping processing for various sensor signals,
A / D conversion processing and the like are executed.

The KCS-IC 14 and the A / F-IC 15 are connected to the microcomputer 20 via a serial communication line 17. Furthermore, the serial communication line 17
EEPROM as a rewritable non-volatile memory
6 is connected. The microcomputer 20 calculates an optimum control amount for the internal combustion engine based on various sensor signals, and outputs a control signal as the calculation result to the output interface circuit 18. Then, various actuators such as an injector (fuel injection valve) 31, an igniter 32, a fuel pump 33, and a throttle motor 34 of the internal combustion engine are driven by a control signal from the output interface circuit 18.

Microcomputer 20 in ECU 10
Is a well-known central processing unit that is a CPU 21, a ROM 22 that stores control programs and data, a RAM 23 that stores various data, and an I / O that outputs control signals to the output interface circuit 18 while receiving signals from the input interface circuit 11. (Input-Output) circuit 24, KCS-IC 14, A / F via serial communication line 17
It is configured as a logical operation circuit including a serial communication module 25 for inputting / outputting input / output signals to / from the IC 15 and the EEPROM 16 and a bus line connecting them. In the RAM 23, an EEPROM described later
A communication buffer TEPBUF for 16 is configured. Further, the EEPROM 16 is a rewritable memory, that is, a rewritable read-only memory that erases once written programs and data, and may be a flash ROM or the like.

Next, the CPU in the microcomputer 20 of the ECU 10 according to an example of the embodiment of the present invention
2 will be described based on the flowchart of FIG. 2 showing a schematic processing procedure of the entire control in 21. The control routine is repeatedly executed by the CPU 21 every predetermined reset.

Referring to FIG. 2, in step S101, initial values are set for those that need to be initialized in their own registers or storage areas in the RAM 23 as initial value setting processing. Next, the process proceeds to step S102, and the registers necessary for executing serial communication as communication setting processing are set. Then, the process proceeds to step S103, and the EEPR
The data in the OM 16 is stored in the RAM 23. Next, the process proceeds to step S104, and it is determined whether the IGSW (ignition switch) 5 is ON. When the determination condition of step S104 is satisfied, that is, when the IGSW 5 is ON, the process proceeds to step S105, and the normal control for the internal combustion engine is executed. Next, the process proceeds to step S106, and the KCS-IC14, A / F-IC15, EEP
Communication with each communication target of the ROM 16 is performed. Here, the communication with the KCS-IC 14 and the A / F-IC 15 is performed at a predetermined timing, and the communication with the EEPROM 16 is performed only when there is write data.

After the process of step S106, the process returns to step S104 and the same process is repeatedly executed. Then, the determination condition of step S104 is not satisfied, that is, I
When the GSW 5 is switched from ON to OFF, the process proceeds to step S107, and the main relay 6 is switched from ON to OFF at a predetermined timing as main relay control processing, so that the power supply from the constant voltage power supply circuit 12 is cut off, and this routine is executed. To finish.

Next, the CPU in the microcomputer 20 of the ECU 10 according to an example of the embodiment of the present invention
Based on the flowcharts of FIGS. 3 and 4 showing the processing procedure for starting serial communication in FIG. 21, description will be made with reference to the timing chart of FIG. The control routine of FIG.
1 is repeatedly executed every 4 ms, and the control routine of FIG. 4 is repeatedly executed by the CPU 21 at every communication completion.

In FIG. 3, in step S201, it is determined whether or not the start is completed. Here, it is determined whether the engine speed NE of the internal combustion engine is less than a predetermined speed, or specifically, whether the start completion flag shown in FIG. 5A is "0" indicating that the start is not completed. When the determination condition of step S201 is not satisfied, that is, when the engine speed NE of the internal combustion engine is equal to or higher than the predetermined speed, specifically, when the start completion flag is "1", the process proceeds to step S202, and FIG.
After the communication starting process with the A / F-IC 15 shown in the serial communication line of (c) is executed, this routine is ended.

On the other hand, when the determination condition of step S201 is satisfied, that is, when the engine speed NE of the internal combustion engine is less than the predetermined speed, specifically, when the start completion flag is "0" and the engine is being started, step S203 is performed. Then, it is determined whether the timing is 8 ms. When the determination condition of step S203 is satisfied, that is, when the timing is 8 ms, the process proceeds to step S204, the communication starting process with the KCS-IC 14 shown in the serial communication line of FIG. 5C is executed, and then this routine ends. To do. On the other hand, step S
When the determination condition of 203 is not satisfied, that is, when the timing is not 8 ms, the process proceeds to step S205, and FIG.
After a communication start-up process, which will be described later, with the EEPROM 16 indicated by the serial communication line is executed, this routine is ended.

Next, in FIG. 4, in step S301, it is determined whether or not the interrupt is due to communication with the A / F-IC 15. The determination condition of step S301 is satisfied, that is,
If it is an interrupt by communication with the A / F-IC 15, the process proceeds to step S302, and a reception process with the A / F-IC 15 is executed. Then, the process proceeds to step S303 and A
It is determined whether the communication with the / F-IC15 is completed. The determination condition of step S303 is not satisfied, that is, A
If the communication with the / F-IC15 is not completed yet, the process proceeds to step S304, the next communication data with the A / F-IC15 is set, the communication is started, and then this routine ends.

On the other hand, when the determination condition of step S301 is not satisfied, that is, when it is not an interrupt by communication with the A / F-IC 15, or when the determination condition of step S303 is satisfied, that is, communication with the A / F-IC 15 is performed. Is completed, the process proceeds to step S305, and it is determined whether the timing is 8 ms. When the determination condition of step S305 is satisfied, that is, when the timing is 8 ms, step S306
Then, it is determined whether the interruption is due to communication with the KCS-IC 14. The determination condition of step S306 is satisfied,
That is, when the interrupt is due to communication with the KCS-IC 14, the process proceeds to step S307, and the receiving process with the KCS-IC 14 is executed. Next, the process proceeds to step S308, and it is determined whether the communication with the KCS-IC 14 is completed. When the determination condition of step S308 is not satisfied, that is, when the communication with the KCS-IC14 is not yet completed, the process proceeds to step S309, the next communication data with the KCS-IC14 is set, and the communication is started, then Exit the routine.

On the other hand, when the determination condition of step S305 is not satisfied, that is, when the timing is not 8 ms, or when the determination condition of step S306 is not satisfied, that is, KCS-I.
When it is not an interrupt by communication with C14, or when the determination condition of step S308 is satisfied, that is, when communication with KCS-IC14 is completed, the process proceeds to step S310, and after communication start processing with EEPROM 16 is executed. , This routine ends.

Next, the CPU in the microcomputer 20 of the ECU 10 according to an example of the embodiment of the present invention
A description will be given with reference to FIG. 7 based on a flowchart of FIG. 6 showing a processing procedure of transfer to the communication buffer TEPBUF for writing in the EEPROM 16 in 21. Here, FIG. 7 is a configuration diagram showing the communication buffer TEPBUF. The control routine of FIG. 6 is repeatedly executed by the CPU 21 for each base process.

In FIG. 6, in step S401, EE
It is determined whether the RAM value stored in the PROM 16 has been updated. Here, the RA stored in the EEPROM 16
The M value is a learning value or data such as destination information written by an external communication device (not shown).
The determination condition of step S401 is not satisfied, that is, EEP
When the RAM value stored in the ROM 16 has not been updated, this routine ends without doing anything. On the other hand, the determination condition of step S401 is satisfied, that is, EEP
When the RAM value stored in the ROM 16 is updated, the process proceeds to step S402, and the updated RAM 23
(2n) is set as the size A. Next, the process proceeds to step S403, and (write command + address) for writing in the EEPROM 16 is stored in the communication buffer TEPBUF shown in FIG. 7 (2 byte).
e minutes). Next, the process proceeds to step S404, and the EEPROM 16 is added to the communication buffer TEPBUF shown in FIG.
Two RAM values for writing to (2 byte)
e minutes).

Next, the process proceeds to step S405, and the interrupt for communication activation is prohibited so that the interrupt is prohibited. Next, the process proceeds to step S406, and the communication buffer TEPB
Base pointer PE indicating the write start address of UF
The EPT is incremented by "+4" as the amount of step S403 and step S404. Then step S4
Moving to 07, the communication buffer T for the RAM 23
The buffer stack SZEPT indicating the buffer size value of EPBUF is incremented by "+4" as the amount for steps S403 and S404. Note that the communication buffer TEPBUF is used as the MAX guard at this time.
The size is set, and the amount beyond that will not be stacked.

Next, the process proceeds to step S408, and the interrupt prohibition in step S405 is released as an interrupt release. Then, the process proceeds to step S409, and step S50
Communication buffer TEPB from size A set in 2
The size (for 2 bytes) stored in the UF is subtracted. Next, the process proceeds to step S410, and it is determined whether the size A is "0". When the determination condition of step S410 is not satisfied, that is, when the size A is not "0", the process returns to step S403 and the same process is repeated.
Then, when the determination condition of step S410 is satisfied, that is, when the size A becomes “0” and the storage in the communication buffer TEPBUF is completed, this routine is ended.

Next, the EEPROM 1 in the communication starting process of step S205 of FIG. 3 and step S310 of FIG.
The communication buffer TEPBUF configuration of FIG. 7 will be described with reference to the flowchart of FIG. The control routine of FIG.
It is repeatedly executed at 1 every 4 ms or every communication completion.

In FIG. 8, in step S501, RA
It is determined whether the buffer stack SZEPT indicating the buffer size value of the communication buffer TEPBUF for M23 is "0". When the determination condition of step S501 is satisfied, that is, when the buffer stack SZEPT is "0" and the write data is not stored in the communication buffer TEPBUF, this routine is ended without doing anything. On the other hand, when the determination condition of step S501 is not satisfied, that is, when the buffer stack SZEPT is not "0" and the write data is stored in the communication buffer TEPBUF, the process proceeds to step S502 to start the serial communication. The required register value is set. Next, proceeding to step S503, 2 bytes of the communication buffer TEPBUF indicated by the interrupt pointer PTEPT are set in the communication data register SPDR. Here, the interrupt pointer PTEPT indicates the start address of the value read from the communication buffer TEPBUF. Next, the process proceeds to step S504, and the interrupt pointer PTEPT indicating the address of the communication buffer TEPBUF is 2 bytes.
The minutes are added. That is, 2 bytes of communication data indicated by the interrupt pointer PTEPT is equal to the communication data register SPDR.
Since it is set to, the pointer is advanced by 2 bytes for the next time. Next, the process proceeds to step S505, and the buffer stack SZEPT is subtracted by 2 bytes. Next, the routine proceeds to step S506, where the serial communication is activated and then this routine is ended.

As described above, the ECU 10 of this embodiment includes the microcomputer 20 having the serial communication module 25, the EEPROM 16 as the rewritable nonvolatile memory connected to the microcomputer 20 via the serial communication line 17, and KCS-IC14 and A / F-IC15 as input / output modules connected in parallel via the EEPROM 16 and the serial communication line 17.
And a RAM 23 having a communication buffer TEPBUF for temporarily storing transmission data for the EEPROM 16, and the microcomputer 20 uses the KCS-IC1.
4, A / F-IC15 and predetermined timing (8ms, 4
ms) and communication with the KCS-IC14, A /
The contents of the communication buffer TEPBUF are confirmed at the timing when communication with the F-IC 15 is not executed, and when transmission data is stored in the communication buffer TEPBUF, communication with the EEPROM 16 is executed via the serial communication line 17. It is a thing. Further, the ECU of the present embodiment
10, the microcomputer 20 has a communication buffer T
When the transmission data is stored in the EPBUF, the communication with the EEPROM 16 is continuously executed until the communication of all the stored transmission data is completed. The ECU 10 of this embodiment checks the contents of the communication buffer TEPBUF immediately after the microcomputer 20 completes the communication with the KCS-IC 14 and the A / F-IC 15.

Therefore, in the ECU 10 of the present embodiment, the transmission data for the EEPROM 16 is sent by the microcomputer 20 to the communication buffer TEPBU of the RAM 23.
When the transmission data is stored in the F, the content is confirmed, and the KCS-IC14, A / F-IC1
When communication with 5 is not executed, communication with the EEPROM 16 by interruption every 4 ms is continuously executed until all transmission data is completed. On the other hand, KCS-IC
14 or the A / F-IC 15 is being executed, the communication buffer TEPBUF is immediately sent when the communication with the KCS-IC 14 or the A / F-IC 15 is completed.
Is confirmed, and EEPR is generated by the communication completion interrupt.
The communication to the OM 16 is continuously executed until all the transmission data are completed. For this reason, during the normal control of the ECU 10, the update data is updated at any time by utilizing the idle time of communication with the KCS-IC 14 or the A / F-IC 15.
By performing the writing process in the OM16, the extra time is not spent in the writing process in the EEPROM 16, and the power supply voltage +
Even if there is a momentary interruption of B, the updated data up to that time is EEPR
It can be surely reflected in the OM16.

Next, the CPU in the microcomputer 20 of the ECU 10 according to an example of the embodiment of the present invention
Based on the flowcharts of FIGS. 9 and 10 showing the modification of the processing procedure of the serial communication activation in No. 21, it will be described with reference to the timing chart of FIG. The control routine of FIG. 9 is repeatedly executed by the CPU 21 at every 4 ms interruption, and the control routine of FIG. 10 is repeatedly executed by the CPU 21 at every interruption of communication.

In FIG. 9, steps S601 to S605 are the steps of FIG. 3 in the above embodiment.
Since it is similar to steps 201 to S205, description thereof will be omitted. After the processing of step S605, step S
After shifting to 606 and setting the flag XDATA indicating the existence of the write data portion to be transmitted to "1", this routine is ended.

Next, in FIG. 10, step S701.
Since step S709 is the same as step S301 to step S309 of FIG. 4 in the above-described embodiment,
The description is omitted. In step S710, EEPR
It is determined whether the interrupt is due to communication with the OM 16. The determination condition of step S710 is not satisfied, that is, EEPR
If it is not an interrupt by communication with the OM16, step S
Then, the processing shifts to 711, and the communication processing with the EEPROM 16 is executed. Here, (write command + address) corresponding to the first 2 bytes is transmitted. Then in step S71
After shifting to 2, the flag XDATA indicating the existence of the write data portion to be transmitted is set to "1", and then this routine is ended.

On the other hand, if the determination condition in step S710 is satisfied, that is, if the interrupt is due to communication with the EEPROM 16, the process proceeds to step S713, the write data partial transmission timing is ON, and the flag XDATA is "1". Is determined. If the determination condition of step S713 is satisfied, that is, it is the write data portion transmission timing to the EEPROM 16 and there is the write data portion to be transmitted, the process proceeds to step S714, and the EEPROM
Step S7 as the transmission processing of the write data portion to 16
Next 2 bytes following 11 (write command + address)
After e (RAM value) has been transmitted and writing to the EEPROM 16 has been executed, this routine is ended.

Next, step S605 of FIG. 9 and FIG.
EEPRO in the communication starting process of step S711 of
Communication request to M16, EEP in step S714
An explanation will be given based on the flowchart of FIG. 11 showing the processing procedure of partial transmission of write data to the ROM 16.

In FIG. 11, steps S801 to S805 are the same as steps S501 to S505 of FIG. 8 in the above-mentioned embodiment, and therefore the description thereof will be omitted. After the process of step S805, the process shifts to step S806, the write data partial transmission timing is OFF, and the flag XDATA is set to "0". Next, the routine proceeds to step S807, where the serial communication is activated and then this routine is ended.

As described above, the ECU 10 of the present modification has the microcomputer 20 having the serial communication module 25, the EEPROM 16 as the rewritable nonvolatile memory connected to the microcomputer 20 via the serial communication line 17, and KCS-IC14 and A / F-IC15 as input / output modules connected in parallel via the EEPROM 16 and the serial communication line 17.
And a RAM 23 having a communication buffer TEPBUF for temporarily storing transmission data for the EEPROM 16, and the microcomputer 20 uses the KCS-IC1.
4, A / F-IC15 and predetermined timing (8ms, 4
ms) and communication with the KCS-IC14, A /
The contents of the communication buffer TEPBUF are confirmed at the timing when communication with the F-IC 15 is not executed, and when transmission data is stored in the communication buffer TEPBUF, communication with the EEPROM 16 is executed via the serial communication line 17. It is a thing. Further, the ECU of this modification
10, the microcomputer 20 has a communication buffer T
When the transmission data is stored in the EPBUF, the EEPROM stores a fixed amount of the transmission data.
The communication with 16 is continuously executed. And
The ECU 10 of this modification confirms the contents of the communication buffer TEPBUF immediately after the microcomputer 20 completes the communication with the KCS-IC 14 and the A / F-IC 15.

Therefore, in the ECU 10 of the present modification, the transmission data for the EEPROM 16 is sent by the microcomputer 20 to the communication buffer TEPBU of the RAM 23.
When the transmission data is stored in the F, the content is confirmed, and the KCS-IC14, A / F-IC1
When communication with 5 is not executed, communication to the EEPROM 16 by interruption every 4 ms is executed for each fixed amount of transmission data. On the other hand, KCS-IC14 or A / F
-When communication with the IC15 is in progress, KCS
-When the communication with the IC 14 or the A / F-IC 15 is completed, the content of the communication buffer TEPBUF is confirmed immediately, and the communication to the EEPROM 16 is executed by a fixed amount by the communication completion interrupt. Therefore, E
During the normal control of the CU 10, at any time using the idle time of communication with the KCS-IC 14 or the A / F-IC 15,
Since the update data is written to the EEPROM 16, no extra time is spent on the writing process to the EEPROM 16, and the update data up to that point is surely reflected in the EEPROM 16 even if the power supply voltage + B is interrupted. can do. In addition, the communication to the EEPROM 16 is executed for each fixed amount of transmission data, so that it is possible to eliminate the influence of the communication with the KCS-IC 14 or the A / F-IC 15 on the normal control of the ECU 10.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an ECU according to an example of an embodiment of the present invention.

FIG. 2 is a flowchart showing a schematic processing procedure of overall control in a CPU in a microcomputer of an ECU according to an example of an embodiment of the present invention.

FIG. 3 is a flowchart showing a processing procedure of serial communication activation in a CPU in a microcomputer of an ECU according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a processing procedure for starting serial communication in a CPU in a microcomputer of an ECU according to an embodiment of the present invention.

FIG. 5 is a timing chart showing processing timing at the time of starting serial communication in the CPU in the microcomputer of the ECU according to the example of the embodiment of the present invention.

FIG. 6 is an E in a CPU in a microcomputer of an ECU according to an example of an embodiment of the present invention.
6 is a flowchart showing a processing procedure of transfer to a communication buffer for writing in an EPROM.

FIG. 7 is an RA of a microcomputer used in an ECU according to an example of an embodiment of the present invention.
It is a block diagram which shows the communication buffer in M.

FIG. 8 is a flowchart showing a processing procedure of a communication request to an EEPROM in the communication start processing of FIGS. 3 and 4.

FIG. 9 is a flowchart showing a modified example of the processing procedure of serial communication activation in the CPU in the microcomputer of the ECU according to the embodiment of the present invention.

FIG. 10 is a flowchart showing a modified example of the processing procedure for starting serial communication in the CPU in the microcomputer of the ECU according to the embodiment of the present invention.

FIG. 11 is a flowchart showing a processing procedure of a communication request to an EEPROM and a write data partial transmission in the communication start processing of FIGS. 9 and 10.

[Explanation of symbols]

10 ECU (electronic control unit) 16 EEPROM (rewritable nonvolatile memory) 17 serial communication line 20 microcomputer 14 KCS-IC (knock determination IC) (input / output module) 15 A / F-IC (A / F detection) IC) (input / output module) 23 RAM (communication buffer TEPBUF) 25 serial communication module

Claims (6)

(57) [Claims] 1. A microcomputer having at least one serial communication module, a rewritable nonvolatile memory connected to the microcomputer via a serial communication line, and a nonvolatile memory via the serial communication line. at least one input and output modules are connected in parallel, the non-volatile temporary store buffer the transmission data to the memory (buffer: buffer storage); and a, the microcomputer the output module and Lee
While the ignition switch is on , communication is performed at every predetermined timing, and the contents of the buffer are confirmed at the timing when communication with the input / output module is not performed, and the transmission data is stored in the buffer. Is stored, the communication with the non-volatile memory is executed via the serial communication line.
In-vehicle electronic control unit. 2. The microcomputer is the entry / exit
Force module and ignition switch are on
The communication is performed every predetermined time of the period.
1. The vehicle-mounted electronic control device according to 1. 3. The microcomputer, when transmission data is stored in the buffer, continuously communicates with the non-volatile memory until communication of all the stored transmission data is completed. The vehicle-mounted electronic control device according to claim 1. Wherein said microcomputer, when the transmission data in the buffer is stored is, the claims and executes the communication with the non-volatile memory by a fixed amount of transmission data are the stored Described in 1.
In-vehicle electronic control unit. Wherein said microcomputer claims 1 to 4, characterized in that to check the contents of the buffer immediately after the communication with the input module is completed
The in- vehicle electronic control device according to any one of 1. 6. At least one serial communication module
A microcomputer having a Via the serial communication line with the microcomputer
Rewritable non-volatile memory connected by Via the non-volatile memory and the serial communication line
At least one input / output module connected in parallel
When, Temporarily stores transmission data to the non-volatile memory
Equipped with a buffer, The microcomputer and the input / output module
Check the contents of the buffer immediately after the communication is completed, and
When transmission data is stored in the buffer,
Communication with the nonvolatile memory is made via a serial communication line.
A vehicle-mounted electronic control device characterized by executing a communication.