JPH0561570A - Control system for vehicle - Google Patents

Abstract

PURPOSE:To improve the reliability of back-up data and to prevent disordered control based on the destroyed back-up data by composing a control data storage area in a RAM of most of bits at plural addresses and composing a check data storage area of specified bits at these addresses. CONSTITUTION:In a RAM 13, a check data storage area 13b is composed of the specified bits at respective addresses X-Xn of a control data storage area 13a and when only one part of the back-up data held in the control data storage area 13a is destroyed, the check data of addresses belonging to the addresses of the destroyed back-up data are destroyed as well. Therefore, by judging the check data in the RAM 13 and check data in a ROM 12, it can be judged whether the back-up data are normal or not. When the back-up data are normal, the data can be used and when they are abnormal, the use can be inhibited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle control system having a backup data abnormality detection function.

[0002]

2. Description of the Related Art A general vehicle air conditioner control system includes a microcomputer, to which a battery voltage is applied even when an ignition key switch is turned off. As a result, the RAM of the microcomputer can store the control data immediately before the ignition key switch is turned off as backup data. Then, after turning on the ignition key switch again, the control can be restarted based on the backup data. In order to use the backup data in this way, it is necessary to initialize the RAM excluding the backup data in the initialization program started in response to turning on of the ignition key switch.

By the way, when the battery is replaced, the voltage application to the microcomputer is stopped, and the backup data in the RAM is also destroyed at this time. Therefore, if the control is performed based on the destroyed backup data after the battery replacement is completed and the ignition key switch is turned on, the control becomes chaotic.

Therefore, the RAM of the microcomputer has an area for storing the control data and a ROM.
An area is provided for storing the same check data as the check data stored in. Then, in the initialization program started by the microcomputer in response to turning on the ignition key switch, the RAM is first
It is determined whether or not the check data of (1) and the check data of the ROM match. That is, if the check data in the RAM matches the check data in the ROM, it is determined that the check data is normal and the backup data held in the control data storage area is also normal. If they do not match, it is determined that the check data has been destroyed and the backup data has also been destroyed. When it is determined that the check data match, the backup data in the RAM is left and the data in other areas are initialized. In this case, control based on backup data can be executed. When it is determined that they do not match, RAM including backup data is included.
Initialize the data of all areas.

[0005]

In the above conventional control system, the check data is stored in an area attached to an address different from the address of the control data storage area. For this reason, if the battery is replaced in an extremely short time, or if the battery is reconnected and connected to the microcomputer again within a short time, some or all of the backup data is destroyed. Nevertheless, the check data may be maintained normally. In this case, when the ignition key switch is turned on, it is determined that the check data in the RAM matches the check data in the ROM, so the initialization is performed while leaving the backup data in the RAM as it is. As a result, chaotic control is executed based on the corrupted backup data.

[0006]

The present invention has been made to solve the above problems, and its gist resides in the control system shown in FIG. This control system includes a microcomputer 10, and a RAM 13 of the microcomputer 10 has an area 13a for storing control data for the controlled object E and an area 13b for storing the same check data as the check data stored in the ROM 12. I have it. By constantly applying the voltage of the battery V to the microcomputer 10, the control data immediately before the ignition key switch S is turned off is held as backup data in the control data storage area 13a. Further, the microcomputer 10
It is provided with an initialization program that starts in response to turning on of the ignition key switch S. This initialization program is a judgment means 1 for judging whether the check data in the RAM 13 matches the check data in the ROM 12.
00, the first initialization means 101 for initializing the RAM excluding the backup data when the determination means determines that they match, and the RAM 13 including the backup data when the determination means determines that they do not match. And a second initialization means 102 for converting the data into a second format. The control system of the present invention is characterized by: RAM above
The control data storage area 13a of 13 has a plurality of addresses X
₁ to Xn is constituted by a majority of the bit, the check data storage area 13b is configured by a specific bit of each address X ₁ to Xn of the control data storage area 13a.

[0007]

In the RAM 13, the check data storage area 13b is the address X of the control data storage area 13a.
Since it is composed of specific bits for each _{1 to} Xn,
When even a part of the backup data held in the control data storage area is destroyed, the check data of the address belonging to the address of the destroyed backup data is also destroyed. Therefore, by determining whether the check data in the RAM 13 matches the check data in the ROM 12, it is possible to accurately determine whether the backup data is normal. As a result, when the backup data is normal, the backup data can be used in the control after the ignition key switch is turned on, and when the backup data is abnormal, the backup data can be reliably prohibited and the execution of chaotic control is prevented. can do.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 shows a control system for controlling the air conditioner E (controlled object), and this control system includes a microcomputer 10. The microcomputer 10 includes a central processing unit (CPU) 11, a read-only memory (ROM) 12 for storing programs and check data, and a random access memory (RAM) 13 as in the case of a normal computer. The voltage of the battery V is constantly applied to the microcomputer 10. Control data from an operation panel and detection data from a sensor are input to the microcomputer 10. The microcomputer 10 calculates based on these control data and detection data, and outputs control signals to the drive circuits of various actuators of the air conditioner E.

[0009] Of the total area of the RAM 13, the address X ₁ to Xn is attached area shown in FIG. 4 is an area for storing control data and check data.
Seven bits from the 0th bit to the 6th bit in each address X _{1 to} Xn are provided as an area for storing control data, and the 7th bit is provided as an area for storing check data.

In the microcomputer 10, when the ignition key switch S is turned on, an initialization program which will be described later is executed in response to this, and thereafter, actual control is performed based on backup data which will be described later or control data from the operation panel. I do. Microcomputer 1
Since the voltage of the battery V is always applied to 0, when the ignition key switch S is turned off, the RAM
The control data from the operation panel immediately before being turned off is held as backup data in the control data storage area of the 0th to 6th bits of the addresses X _{1 to} Xn of 13. After that, if the connection between the battery V and the microcomputer 10 is maintained, the data in the RAM 13 is maintained without being destroyed, and the battery V can be replaced for replacement of the battery V.
When the connection between the microcomputer 10 and
The data of AM13 is destroyed. When the battery V and the microcomputer 10 are disconnected from each other for a short time and are connected again, only part of the data in the RAM 13 is destroyed.

Next, the initialization program of FIG. 3 executed when the ignition key switch S is turned on will be described in detail. First, the check data of RAM13 is ROM
It is determined whether or not the check data of 12 matches (step 100). When an affirmative decision is made in this step 100, the data of all areas of the RAM 13 excluding the backup data are initialized (step 101). When a negative determination is made in step 100, the data of all areas of the RAM 13 including the backup data is initialized (step 102). In these steps 101 and 102, R
The seventh bit AM addresses X ₁ to Xn by writing the check data of ROM, the initialization of the check data. The initialization of the check data may be omitted in step 101.

In the RAM 13, the check data storage area is the address X _{1 to} Xn of the control data storage area.
Since it is composed of a specific bit (7th bit) for each, even if a part of the backup data held in the control data storage area is destroyed, the check data of the address belonging to the address of this destroyed backup data Is destroyed at the same time. Therefore, RAM1
By determining whether the check data of No. 3 matches the check data of the ROM 12, it is possible to accurately determine whether the backup data is normal. As a result, when the backup data is normal, the backup data can be used in the control after the ignition key switch S is turned on, and when the backup data is abnormal, the use of the backup data is surely prohibited to prevent the execution of chaotic control. be able to.

The present invention is not limited to the above embodiment, and various modes are possible. For example, the check data storage area may be composed of a plurality of bits for each address of the control data storage area. It is not necessary to provide a specific bit for storing the check data at the address where the control data that does not require backup is stored.

[0014]

As described above, according to the present invention, RA
Since the backup data and the check data are stored in the same address of M, it can be accurately determined whether the backup data is normal or abnormal by determining whether the check data is normal or abnormal. As a result, chaotic control based on abnormal backup data can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control system of the present invention.

FIG. 2 is a block diagram showing an embodiment of a control system of the present invention.

FIG. 3 is a flowchart showing an initialization program executed by the microcomputer of FIG.

FIG. 4 is a diagram showing an area for storing control data and check data in the RAM of FIG.

[Explanation of symbols]

 E ... Control object (air conditioner) V ... Battery S ... Ignition key switch 10 ... Microcomputer 11 ... CPU 12 ... ROM 13 ... RAM 13a ... Control data storage area 13b ... Check data storage area 100 ... Judgment means 101 ... First initial Initializing means 102 ... Second initializing means

Claims (1)

[Claims] 1. A microcomputer is provided, and a RAM of the microcomputer has an area for storing control data for a control target and an area for storing the same check data as the check data stored in the ROM.
By constantly applying the battery voltage to the microcomputer, the control data immediately before the ignition key switch is turned off is retained as backup data in the control data storage area, and the microcomputer responds to the turning on of the ignition key switch. An initialization program for starting the program is provided, and the initialization program determines whether the check data in the RAM matches the check data in the ROM, and the backup data when the determination means determines that the check data matches. In a vehicle control system provided with a first initialization unit that initializes the RAM except for the above, and a second initialization unit that initializes the RAM including backup data when the determination unit determines that they do not match, Control data storage area of RAM Is composed of most bits of a plurality of addresses, and the check data storage area is composed of specific bits for each address of the control data storage area.