On-vehicle control apparatus

• US 20070250254A1
• Filed: 08/21/2006
• Published: 10/25/2007
• Est. Priority Date: 03/24/2006
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Kimoto, Yasuhiro
• Granted Patent: US 8,036,786 B2
• Time in Patent Office: Days
• US Class Current: 701/114
• CPC Class Codes: G06F 8/65 Updates security arrangements therefor G06F21/57
• CPC Class Codes: G06F 9/4401 Bootstrapping security arrangements therefor G06F21/57

Abstract

Provided is an on-vehicle control apparatus capable of automatically initializing control variables in a backup RAM only in rewriting a control program in the market. The on-vehicle control apparatus includes a CPU for controlling an on-vehicle device according to a control program, a non-volatile ROM for storing the control program therein, a backup RAM for storing control variables therein, a backup power supply circuit for supplying power to the backup RAM, a boot program for rewriting the control program, an address changeover circuit for making a changeover in execution address, and a memory rewrite unit. The memory rewrite unit outputs a rewrite signal, a command signal group including a command for activating the boot program, and an erasure command signal for erasing a diagnostic code. The control program initializes the control variables in the backup RAM in response to the erasure command signal when being activated after having been rewritten.

Claims

1. An on-vehicle control apparatus, comprising:

a CPU for controlling an on-vehicle device based on a control program using various control variables;

a rewritable non-volatile memory for storing the control program;

a backup RAM for storing the control variables therein;

a backup power supply circuit for supplying power to the backup RAM;

a boot program for causing the CPU to rewrite the control program;

an address changeover circuit for making a changeover in an execution address of the CPU to the boot program in rewriting the control program; and

a memory rewrite unit, wherein;

the memory rewrite unit outputs a rewrite signal for causing the address changeover circuit to operate, a command signal group including a command for activating the boot program, and an erasure command signal for erasing a diagnostic code after the control program has been rewritten; and

the control program initializes the control variables in the backup RAM in response to the erasure command signal when being activated after having been rewritten.

3. An on-vehicle control apparatus according to claim 1, further comprising an electrically erasable and rewritable EEPROM for storing therein the control variables stored in the backup RAM,

wherein the control program initializes the control variables in the backup RAM and then stores a predetermined one of the control variables in the EEPROM into the backup RAM.

4. An on-vehicle control apparatus according to claim 1, wherein the memory rewrite unit outputs an initialization command signal for initializing the control variables in the backup RAM as the erasure command signal.

7. An on-vehicle control apparatus according to claim 3, wherein the memory rewrite unit outputs an initialization command signal for initializing the control variables in the backup RAM as the erasure command signal.

2. An on-vehicle control apparatus, comprising:

a CPU for controlling an on-vehicle device based on a control program using various control variables;

a rewritable non-volatile memory for storing the control program therein;

a backup RAM for storing the control variables therein;

a backup power supply circuit for supplying power to the backup RAM;

a boot program for causing the CPU to rewrite the control program;

an address changeover circuit for making a changeover in an execution address of the CPU to the boot program in rewriting the control program; and

a memory rewrite unit, wherein;

the memory rewrite unit outputs a rewrite signal for causing the address changeover circuit to operate, a command signal group including a command for activating the boot program, and an erasure command signal for erasing a diagnostic code after the control program has been rewritten; and

the control program compares a criterial value in the non-volatile memory with a predetermined value in the backup RAM, initializes the control variables in the backup RAM when the control program determines that the criterial value does not coincide with the predetermined value, sets the predetermined value to an abnormal value in response to the erasure command signal when being activated after having been rewritten, and initializes the control variables in the backup RAM in response to a failure in coincidence between the abnormal value and the criterial value when being activated next time.

5. An on-vehicle control apparatus according to claim 2 further comprising an electrically erasable and rewritable EEPROM for storing therein the control variables stored in the backup RAM,

wherein the control program initializes the control variables in the backup RAM and then stores a predetermined one of the control variables in the EEPROM into the backup RAM.

6. An on-vehicle control apparatus according to claim 2, wherein the memory rewrite unit outputs an initialization command signal for initializing the control variables in the backup RAM as the erasure command signal.