Vehicle built-in electronic control apparatus

• US 20020040261A1
• Filed: 04/20/2001
• Published: 04/04/2002
• Est. Priority Date: 09/29/2000
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Hashimoto, Kohji, Nakamoto, Katsuya, Kitta, Mitsuhiro, Gokan, Hiroshi
• Granted Patent: US 6,678,586 B2
• Time in Patent Office: Days
• US Class Current: 701/1
• CPC Class Codes: B60W 2050/0005 Processor details or data handling, e.g. memory registers or chip architecture
• CPC Class Codes: G06F 11/0757 by exceeding a time limit, i.e. time-out, e.g. watchdogs
• CPC Class Codes: G06F 11/0796 Safety measures, i.e. ensuring safe condition in the event of error, e.g. for controlling element

Abstract

In a vehicle built-in electronic control apparatus, second control programs are written, second RAM memory for calculation processing and second input/output ports, and a serial-parallel converter for full duplex two-way serial communication for mutually conducting data communications between the main CPU and the sub CPU in operation of the controlled vehicle, and at the time of starting operation of the controlled vehicle, a part of the control constants stored in the first nonvolatile memory is transferred to the second RAM memory through the serial-parallel converter for the serial communication and the sub CPU performs predetermined calculation based on the contents of the second control programs of the second nonvolatile memory and the contents of the control constants transferred to the second RAM memory.

Claims

1. A vehicle built-in electronic control apparatus fed from a vehicle built-in battery through a power switch, comprising:

a main CPU including first nonvolatile memory in which at least first control programs and control constants in correspondence with a controlled vehicle are written from an external tool;

a first RAM memory for calculation processing and first input/output ports;

a sub CPU including second nonvolatile memory in-which second control programs are written a second RAM memory for calculation processing and second input/output ports; and

a serial-parallel converter for full duplex two-way serial communication for mutually conducting data communications between the main CPU and the sub CPU in operation of the controlled vehicle;

wherein at the time of starting operation of the controlled vehicle, a part of the control constants stored in the first nonvolatile memory is transferred to the second RAM memory through the serial-parallel converter for the serial communication and the sub CPU performs predetermined calculation based on the contents of the second control programs of the second nonvolatile memory and the contents of the control constants transferred to the second RAM memory.

2. A vehicle built-in electronic control apparatus as defined in claim 1, wherein there are provided a second power terminal for feeding power to each the CPU and the memory, and a first power terminal which is connected to the vehicle built-in battery without intervention of the power switch and feeds power to at least the second RAM memory, and even when the power switch is broken, the contents of at least the second RAM memory are held by the feeding from the first power terminal.

3. A vehicle built-in electronic control apparatus as defined in claim 1, wherein there is further provided third nonvolatile memory, and the contents of the second RAM memory are saved in the third nonvolatile memory at the time of breaking the power switch and are transferred from the third nonvolatile memory to the second RAM memory at the time of again turning on the power switch.

4. A vehicle built-in electronic control apparatus as claimed in claim 1, wherein the main CPU and the sub CPU comprise control constant sending means for sending the control constants stored in the first nonvolatile memory to the sub CPU when the contents of the first nonvolatile memory have been changed at the time of starting operation of the controlled vehicle, direct request means capable of performing an interruption request of data sending from the sending side CPU to the receiving side CPU when the contents of the first nonvolatile memory have not been changed, irregular data sending means for sending the sending data as irregular data in the case that the interruption request by this direct request means is absent but there is a need for interruption sending from the sending side CPU to the receiving side CPU and the case that there is no need for the interruption sending but a data request from the receiving side CPU to the sending side CPU is present, and regular data sending means for regularly sending the sending data as regular data in the case that all the interruption request by the direct request means, the need for the interruption sending and the data request from the receiving side CPU to the sending side CPU are absent.

5. A vehicle built-in electronic control apparatus as claimed in claim 1, wherein a direct memory access controller is connected to at least one data bus of the sides of the main CPU or the sub CPU and sending data received through the serial-parallel converter for the serial communication is stored in the receiving side RAM memory without intervention of the receiving side CPU.

6. A vehicle built-in electronic control apparatus as claimed in claim 1, wherein the main CPU and the sub CPU comprise sum check means for making an error check of received data by the serial-parallel converter for the serial communication in the receiving side CPU, resending request means for requesting the resending of the received data to the sending side CPU if this sum check means determines that an error is present in the received data, and time-out check means for determining whether an interval between sending start time from the sending side CPU to the receiving side CPU and verification answer receiving time of the received data from the sum check means is within a predetermined time interval or not.

7. A vehicle built-in electronic control apparatus as claimed in claim 1, wherein the main CPU comprises reset output means for monitoring a watch dog signal of the sub CPU and a time-out check result of communication and generating a reset pulse output at the time of operation abnormality of the sub CPU to restart the sub CPU, and a watch dog timer circuit for monitoring a watch dog signal of the main CPU and generating a reset pulse output at the time of operation abnormality to restart the main CPU.

8. A vehicle built-in electronic control apparatus as defined in claim 7, wherein there are provided a memory element reset by breaking or again turning on the power switch while storing generation of the reset pulse output, an output stop circuit for stopping a driving of a part of loads in response to an operation of this memory element, and alarm and indication means for giving an alarm and indication of operation abnormality in response to the operation of the memory element.