Vehicle-mounted electronic control apparatus

• US 6,640,259 B2
• Filed: 03/22/2001
• Issued: 10/28/2003
• Est. Priority Date: 09/19/2000
• Status: Expired due to Term

• 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
• Primary Examiner(s): Huynh, Kim
• Assistant Examiner(s): Mai, Rijue
• Application Number:
  US09/813,947
• Publication Number:
  US 20020035650A1
• Time in Patent Office: 950 Days
• Field of Search: 710/1, 710/5, 710/18, 710/29, 710/33, 710/36, 710/105, 710/100, 712/225, 712/10, 712/32, 712/245, 709/200, 709/201, 709/205
• US Class Current: 710/5
• CPC Class Codes: F02D 41/266 the computer being backed-up or assisted by another circuit, e.g. analogue

Abstract

A vehicle-mounted electronic control apparatus comprises:

a main CPU including a first nonvolatile memory in which at least control programs and control constants, in correspondence with types of controlled vehicles, transmitted from an external tool are written, the main CPU including a first RAM for calculation processing;

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

a serial-parallel converter for serial communication adapted to transmit a plurality of input signals, which are input to the sub CPU, to the main CPU,

wherein a plurality of filter constants corresponding to the plurality of input signals are stored in at least one of the first and second nonvolatile memory; and

the sub CPU has a digital filter section adapted to perform predetermined calculation based on the filter constants to transmit a result of the calculation to the main CPU.

Claims

1. A vehicle-mounted electronic control apparatus comprising:

a main CPU including a first nonvolatile memory in which at least control programs and control constants, in correspondence with types of controlled vehicles, transmitted from an external tool are written, the main CPU including a first RAM for calculation processing;

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

a serial-parallel converter for serial communication adapted to transmit a plurality of input signals, which are input to the sub CPU, to the main CPU,

wherein a plurality of filter constants corresponding to the plurality of input signals are stored in at least one of the first and second nonvolatile memory; and

the sub CPU has a digital filter section adapted to perform predetermined calculation based on the filter constants to transmit a result of the calculation to the main CPU.

2. The vehicle-mounted electronic control apparatus according to claim 1, wherein the serial-parallel converter for serial communication transmits a plurality of control output signals calculated by the main CPU to the sub CPU and the serial-parallel converter supplies the plurality of control output signals to an external load through an output interface circuit connected to a data bus of the sub CPU.

3. The vehicle-mounted electronic control apparatus according to claim 1, wherein the plurality of input signals input to the sub CPU are a plurality of analog signals input through a noise filter including at least positive and negative clip diodes and a capacitor with a small capacity;

the plurality of analog signals are conducted digital conversion into a plurality of digital converted values through an A/D converter and a digital filter including a switched capacitor periodically charged and discharged by a changeover switch and a setting unit of a charge and discharge cycle; and

the digital filter section performs predetermined calculation using the digital converted values to transmit a result of the calculation to the main CPU.

4. The vehicle-mounted electronic control apparatus according to claim 1, wherein the plurality of input signals input to the sub CPU are a plurality of on-off signals input through a bleeder resistor with a low resistance acting as a load to an input switch, a noise filter including a series resistor with a high resistance and a capacitor with a small capacity, and a comparator for level determination having a hysteresis function;

the digital filter section has an input confirmation section adapted to sample outputs from the comparator for level determination in a predetermined cycle to make an ON determination when positive results of the continuous plurality of sampling results are 50% or more and to make an OFF determination if the positive results of the continuous plurality of sampling results are less than 50%; and

outputs of the input confirmation section are transmitted to the main CPU.

5. The vehicle-mounted electronic control apparatus according to claim 4, wherein the digital filter section comprises a setting section adapted to set at least one of a sampling cycle and the number of logical determination points of the comparator for level determination.

6. The vehicle-mounted electronic control apparatus according to claim 4, wherein a determination value to make the input confirmation section output an ON is variable in a range of proportion of the positive results in the plurality of sampling results from 50% to 100%.

7. The vehicle-mounted electronic control apparatus according to claim 1, further comprising a retransmission determination section,

wherein the filter constants are constants, which are corresponding to types of controlled vehicles, written in the first nonvolatile memory of the main CPU;

the filter constants are transferred to the second RAM of the sub CPU through the serial-parallel converter for serial communication;

a sum check of setting constants including the filter constants used in the digital filter section of the sub CPU is performed in the sub CPU;

when a check sum error occurs, the retransmission determination section again transfers the filter constants from the main CPU to the sub CPU.

8. The vehicle-mounted electronic control apparatus according to claim 1, further comprising:

a transfer section adapted to transfer the filter constants to the first RAM;

a control constant correction section adapted to correct control constants including the filter constants stored in the first RAM; and

a control constant transfer section adapted to transfer the corrected control constants to the second RAM of the sub CPU through the serial-parallel converter for serial communication,

wherein the filter constants are constants, which are corresponding to the types of controlled vehicles, written in the first nonvolatile memory of the main CPU; and

the control constants are used as setting constants of the digital filter section of the sub CPU.

9. The vehicle-mounted electronic control apparatus according to claim 1, wherein an input/output interface circuit for high-speed processing capable of inputting/outputting to the main CPU directly without intervention of the sub CPU is connected to a data bus of the main CPU;

and

a signal input to the sub CPU through the input/output interface circuit is monitored by the sub CPU to transmit a monitor result to the main CPU.

10. The vehicle-mounted electronic control apparatus according to claim 1, further comprising:

a removable connector adapted to connect an external tool;

a serial communication interface adapted to connect the external tool to the main CPU; and

a writing mode determination section adapted to respond to operations of a part of the plurality of input signals supplied to the sub CPU and to generate a writing control signal from the sub CPU based on programs stored in the second nonvolatile memory,

wherein the writing control signal is supplied to a writing control terminal of the main CPU to transfer and write the control programs and the control constants from the external tool to the first nonvolatile memory.