JPH04362437A - Control method of vehicle - Google Patents

Abstract

PURPOSE:To reduce the effect of a lead time necessary for making a mask ROM from the decision of control specifications to the production of a vehicle to shorten the time for development. CONSTITUTION:Control data in an OTPROM in a 2nd microcomputer are transmitted to a 1st. microcomputer (S101), and when the transmission of all the control data is completed, a check sum of the transmitted data are calculated (S103). Then the check sum transmitted from a main CPU in the 1st. microcomputer is received (S104), and the received check sum is compared with the check sum of the transmitted data to verify whether they are coincident with each other or not (S105), and when they are not coincident with each other, the control data in the OTPROM are transmitted again. When the check sum from the main CPU and that of transmitted data are coincident with each other, a control starting command is transmitted to the main CPU (S106) to shift to a normal control.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a vehicle using a plurality of microcomputers.

0002

BACKGROUND OF THE INVENTION In recent years, many vehicles such as automobiles are equipped with a plurality of computers for control.
A technology has been disclosed that includes a microcomputer and divides the processing of multiple types of control items.

By the way, a microcomputer installed in a car has a CPU, ROM, RAM, and peripheral I/O.
In general, there are many one-chip microcomputers in which each element is integrated into one LSI, compared to general-purpose microcomputers that are composed of several chips such as ROM is used.

[0004] Programs and data are written to this mask ROM during the manufacturing stage of the LSI wafer of a one-chip microcomputer, so it is suitable for mass production and has high reliability. However, it has little cost advantage for small volume production, and the system specifications The lead time from the time the product is decided until the product is completed takes several months, and there is little freedom to change specifications during the development period.

[0005] To deal with this, Japanese Patent Laid-Open No. 61-6455
No. 6 discloses that an electronic control device is provided with an internal ROM in which information indicating a general-purpose control program resides and an external ROM in which information expressing a control sequence for executing predetermined control in an intermediate language format is stored. A technique has been disclosed that improves followability of specification changes.

[0006]

[Problem to be solved by the invention] However, usually,
When determining the specifications for a one-chip microcomputer, the last specification to be determined is the control data.Even if the specifications of the control program are finalized and debugging is completed, if the control data is not determined, it will be difficult to manufacture the one-chip microcomputer. However, the period from development to commercialization becomes longer.

The present invention has been made in view of the above circumstances, and provides a vehicle capable of reducing the influence of the lead time required for manufacturing mask ROM from the determination of vehicle control specifications to commercialization, and shortening the development period. The purpose is to provide a control method for

[0008]

[Means for Solving the Problems] A vehicle control method according to a first invention includes a first microcomputer having a mask ROM and a second microcomputer having a one-time programmable ROM, The present invention is characterized in that after the control data in the ROM is transferred from the second microcomputer to the first microcomputer, control of the vehicle is started.

[0009] Furthermore, a vehicle control method according to a second invention is a method for controlling a vehicle according to the first invention.
It is checked whether the control data transferred from the second microcomputer to the first microcomputer is normal or not. If the transferred control data is not normal, the control data is transferred from the second microcomputer to the first microcomputer again. The control data in the one-time programmable ROM is transferred to the one-time programmable ROM.

0010

[Operation] In the vehicle control method according to the first invention, control data in the one-time programmable ROM is first transferred from the second microcomputer to the first microcomputer, and then vehicle control is started. Ru.

Further, in the vehicle control method according to the second invention, in the vehicle control method according to the first invention, the control data in the one-time programmable ROM is transferred from the second microcomputer to the first microcomputer. When the control data is transferred, it is checked whether the transferred control data is normal or not, and if it is not normal, the control data in the one-time programmable ROM is transferred from the second microcomputer to the first microcomputer again. do.

0012

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings show one embodiment of the present invention, and FIG. 1 shows a sub-CP
A flowchart showing the startup processing procedure on the U side, FIG. 2 is a flowchart showing the startup processing procedure on the main CPU side,
FIG. 3 is a circuit diagram of the control device.

In FIG. 3, reference numeral 1 denotes an electronic control unit (ECU) installed in a vehicle such as an automobile.
CU1 is two one-chip microcomputers, for example, engine air-fuel ratio control (fuel injection control).
, a first microcomputer 2 that performs ignition timing control, etc., and a second microcomputer 3 that performs, for example, knock detection processing, and receives input signals from various sensors, switches, etc. (not shown). An input processing circuit for processing, an A/D converter for converting analog input signals from sensors into digital signals, an output processing circuit for driving various actuators, a power supply circuit, etc. are added.

The first microcomputer 2 includes a main CPU 4, a mask ROM 5, a RAM 6, a timer 7,
An input/output (I/O) interface 8, a serial interface (SCI) 9, etc. are integrated into one chip, and each of these elements is connected to each other by a bus line 10.

[0015] Also, the second microcomputer 3
is sub CPU11, one time programmable ROM
(OTPROM) 12, RAM 13, timer 14, I/
The O interface 15, SCI 16, etc. are integrated into one chip, and each of these elements is connected to the bus line 17.
The one-time programmable ROM 12 includes, for example, UVEPROM, EE
PROM etc. are used.

The first microcomputer 2 and the second microcomputer 3 are connected to each other via SCIs 9 and 16 by a serial line for transmitting and receiving a clock signal CLOCK, a transmission signal TX, and a reception signal RX. In synchronization with the clock signal CLK supplied from the first microcomputer 2, clock-synchronous bidirectional communication is performed between the first microcomputer 2 and the second microcomputer 3.

In the first microcomputer 2, fixed data such as control programs such as fuel injection control and ignition timing control are stored in the mask ROM 5 during the manufacturing stage.
On the other hand, the second microcomputer 3, for example,
Control data specific to each vehicle model, such as a basic fuel injection amount map, ignition timing map, and control constants, is stored in the OTPROM 12 in accordance with the product completion period of the first microcomputer 2.
written to.

The first microcomputer 2 having the mask ROM 5 takes several months to manufacture;
The second microcomputer 3 having the OTPROM 12 can be manufactured in a fraction of the time period required for the first microcomputer 2.

Therefore, after the specification determination and debugging of the control program are completed, the first microcomputer 2 can be immediately manufactured. During the manufacturing period of the first microcomputer 2, the second microcomputer 2 can be manufactured. The control data to be written into the OTPROM 12 of No. 3 can be determined through experiments or the like.

[0020] This shortens the overall development period,
Furthermore, it is possible to significantly reduce costs by reducing the total number of man-hours.

Next, in the ECU 1 having such a configuration, control data is transferred from the second microcomputer 3 to the first microcomputer 2 at the time of startup, and thereafter the control data shifts to normal control. This startup process will be explained below.

The flowchart shown in FIG. 1 is a startup process executed by the sub CPU 11 of the second microcomputer 3. First, in step S101, the OTP
The control data in the ROM 12 is transmitted to the first microcomputer 2 via the SCI 16.

Next, the process advances to step S102, and it is checked whether or not the transmission of all control data has been completed. If the transmission has not been completed, the process returns to step S101 to continue transmitting the control data, and the transmission is completed. If finished,
The process advances to step S103.

In step S103, a checksum of the transmitted data is calculated, and in step S104, the checksum transmitted from the main CPU 4 side of the first microcomputer 2 is received.

[0025] Then, in step S105, the main CPU
The side checksum and the checksum of the transmitted data are compared to see if these checksums match. If they do not match, the process returns to step S101 described above.
The control data in the OTPROM 11 is transmitted again.

[0026] Also, in step S105 above, the main C
If the checksum on the PU side and the checksum of the transmission data match, the process advances to step S106, where a control start command is sent to the main CPU 4 side and the process shifts to normal control.

On the other hand, on the first microcomputer 2 side, the startup process shown in FIG. 2 is executed by the main CPU 4, and in step S201, the sub CPU
Receives control data from the U11 side and stores it in the RAM6.

Next, in step S202, it is checked whether reception of all control data has been completed, and if reception has not been completed, the process returns to step S201 to continue receiving control data, and if reception is not completed. If finished, the process advances to step S203.

In step S203, a checksum of the received data is calculated, and in step S204, the calculated checksum is sent to the sub CPU 11 side. In step S205, a control start command sent from the sub CPU 11 side is received. After receiving this control start command, the controller shifts to normal control.

Note that the present invention is not limited to the embodiments, and the first microcomputer 2 and the second microcomputer 3 may be separate ECUs, and the control by each microcomputer may be mutually controlled. It may be independent.

[0031]

As described above, according to the present invention, it is possible to reduce the influence of the lead time caused by the mask ROM from the determination of vehicle control specifications to commercialization, and to shorten the development period. Therefore, excellent effects such as being able to reduce the total number of man-hours and costs can be achieved.

[Brief explanation of the drawing]

[Figure 1] Flowchart showing the startup processing procedure on the sub CPU side

[Figure 2] Flowchart showing the startup processing procedure on the main CPU side

[Figure 3] Circuit configuration diagram of control device

[Explanation of symbols]

2 First microcomputer 3 Second
Microcomputer 5 Mask ROM

Claims (2)

[Claims] 1. A first microcomputer having a mask ROM and a second microcomputer having a one-time programmable ROM, wherein control data in the one-time programmable ROM is transmitted from the second microcomputer to the second microcomputer. 1. A method for controlling a vehicle, which comprises starting control of the vehicle after the data is transferred to the microcomputer of No. 1. 2. Check whether the control data transferred from the second microcomputer to the first microcomputer is normal or not, and if the transferred control data is not normal, the control data is transferred to the second microcomputer again. 2. The method of controlling a vehicle according to claim 1, further comprising transferring control data in said one-time programmable ROM from a computer to said first microcomputer.