Control apparatus for automobile engine including microcomputer which may be programmed after mounting on a circuit board

• US 5,602,738 A
• Filed: 10/27/1993
• Issued: 02/11/1997
• Est. Priority Date: 02/01/1990
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Sasaki, Shoji
• Primary Examiner(s): Gossage, Glenn
• Application Number:
  US08/141,703
• Time in Patent Office: 1,203 Days
• Field of Search: 395/425, 395/430, 365/51, 365/52, 365/189.03, 365/201, 364/431.04, 364/431.12
• US Class Current: 701/115
• CPC Class Codes: F02D 2400/18 Packaging of the electronic circuit in a casing
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/249 Methods for preventing the loss of data
• CPC Class Codes: F02D 41/3005 Details not otherwise provided for
• CPC Class Codes: G06F 8/60 Software deployment
• CPC Class Codes: G06F 9/24 Loading of the microprogram
• CPC Class Codes: G11C 16/102 External programming circuits, e.g. EPROM programmers; In-circuit programming or reprogramming; EPROM emulators
• CPC Class Codes: G11C 5/00 Details of stores covered by group G11C11/00
• CPC Class Codes: G11C 7/00 Arrangements for writing information into, or reading information out from, a digital store G11C5/00 takes precedence; auxiliary circuits for stores using semiconductor devices G11C11/4063, G11C11/413

Abstract

A control apparatus and associated method for controlling a single chip microcomputer which has a memory for storing data. The microcomputer is operable in accordance with program data stored in the memory, which may be a programmable read only memory (PROM). The data may be stored in the memory after the microcomputer has been mounted on a circuit board. The control apparatus includes the programmable memory, a control unit for controlling the storing of program data into the memory, a plurality of input terminals for receiving the program data from an external source, and isolation circuitry for isolating the microcomputer during writing of program data into the memory. The control apparatus may be used for controlling an internal combustion engine of an automobile.

Claims

1. A control apparatus for controlling an internal combustion engine of an automobile, said control apparatus comprising:

a circuit board having a plurality of input terminals and a plurality of output terminals;

a microcomputer mounted on said circuit board and having an input and an output, said input adapted for connection via a first one of said input terminals to a sensor, external to said circuit board, which senses an operating condition of the automobile, said output adapted for connection via one of said output terminals to an actuator, external to said circuit board, for controlling an operating condition of said internal combustion engine in accordance with the sensed operating condition;

program memory means in said microcomputer for storing a control program to control said microcomputer;

write control means mounted on said circuit board and responsive to a Write control signal from said microcomputer, for controlling said program memory means to permit writing of the control program into said program memory means;

input means mounted on said circuit board and connected to a second one of said input terminals for receiving from a source, external to said circuit board, the control program to be written into said program memory means when said program memory means is under control of said write control means; and

isolation means mounted on said circuit board, connected to said microcomputer, to said first one of said input terminals, and to said one of said output terminals, and responsive to the write control signal, for electrically isolating said microcomputer from the sensor and the actuator when said write control means is controlling said program memory means, to inhibit input of signals from the sensor and output of signals to the actuator during writing of the control program into said program memory means.

2. A control apparatus according to claim 1, wherein said microcomputer is adapted for operation in one of a write mode, for writing the control program into said program memory means, and a normal operation mode, for applying output signals to the actuator to control the operating condition of the engine, and wherein said write control means is further responsive to the write control signal from said microcomputer, to cause said microcomputer to operate in a selected one of the write mode and the normal operation mode.

3. A control apparatus according to claim 1, wherein said program memory means is a programmable read only memory.

4. A control apparatus according to claim 1, wherein said one of said output terminals is adapted for connection to an ignition coil of the internal combustion engine.

5. A control apparatus according to claim 1, wherein said one of said output terminals is adapted for connection to a fuel injector of the internal combustion engine.

6. A control apparatus according to claim 1, wherein said isolation means comprises a first buffer circuit coupling said first one of said input terminals to said microcomputer and a second buffer circuit coupling said microcomputer to said one of said output terminals, each buffer circuit being responsive to the write control signal to assume a first state inhibiting passage of signals through that buffer circuit and responsive to absence of the write control signal to assume a second state permitting passage of signals through that buffer circuit.

7. A control apparatus according to claim 1, wherein said write control means comprises switching means responsive to-the write control signal for applying a voltage signal to said program memory means, and said program memory means is responsive to the voltage signal to permit writing of the control program in said program memory means.

8. A control apparatus according to claim 1, wherein said microcomputer is a single chip microcomputer.

9. A control apparatus for controlling an internal combustion engine of an automobile, said control apparatus comprising:

a circuit board having a plurality of input terminals and a plurality of output terminals;

a microcomputer mounted on said circuit board and having an input and an output, said input adapted for connection via a first one of said input terminals to a sensor, external to said circuit board, which senses an operating condition of the automobile, said output adapted for connection via one of said output terminals to an actuator, external to said circuit board, for controlling an operating condition of said internal combustion engine in accordance with the sensed operation condition;

program memory means in said microcomputer for storing a control program to control said microcomputer;

write control means surface mounted on said circuit board and responsive to a write control signal for controlling said program memory means to permit writing of the control program into said program memory means;

input means surface mounted on said circuit board and connected to a second one of said input terminals for receiving from a source, external to said circuit board, the control program to be written into said program memory means when said program memory means is under control of said write control means; and

isolation means mounted on said circuit board, connected to said microcomputer, to said first one of said input terminals, and to said one of said output terminals, and responsive to the write control signal, for electrically isolating said microcomputer from the sensor and the actuator when said write control means is controlling said program memory means, to inhibit input of signals from the sensor and output of signals to the actuator during writing of the control program into said program memory means.

10. A control apparatus according to claim 9, wherein said microcomputer is adapted for operation in one of a write mode, for writing the control program into said program memory means, and a normal operation mode, for applying output signals to the actuator to control the operating condition of the engine, and wherein said write control means is further responsive to the write control signal to cause said microcomputer to operate in a selected one of the write mode and the normal operation mode.

11. A control apparatus according to claim 9, wherein said program memory means is a programmable read only memory.

12. A control apparatus according to claim 9, wherein said one of said output terminals is adapted for connection to an ignition coil of the internal combustion engine.

13. A control apparatus according to claim 9, wherein said one of said output terminals is adapted for connection to a fuel injector of the internal combustion engine.

14. A control apparatus according to claim 9, wherein said isolation means comprises a first buffer circuit coupling said first one of said input terminals to said microcomputer and a second buffer circuit coupling said microcomputer to said one of said output terminals, each buffer circuit being responsive to the write control signal to assume a first state inhibiting passage of signals through that buffer circuit and responsive to absence of the write control signal to assume a second state permitting passage of signals through that buffer circuit.

15. A control apparatus according to claim 9, wherein said write control means comprises switching means responsive to the write control signal for applying a voltage signal to said program memory means, and said program memory means is responsive to the voltage signal to permit writing of the control program in said program memory means.

16. A control apparatus according to claim 9, wherein said microcomputer is a single chip microcomputer.

17. A control apparatus for controlling an internal combustion engine of an automobile, said control apparatus comprising:

a circuit board having a plurality of input terminals and a plurality of output terminals;

a single chip microcomputer sealed in plastic, surface mounted on said circuit board, and having an input and an output, said input adapted for connection via a first one of said input terminals to a sensor, external to said circuit board, which senses an operating condition of the automobile, said output adapted for connection via one of said output terminals to an actuator, external to said circuit board, for controlling an operating condition of said internal combustion engine in accordance with the sensed operating condition;

program memory means in said microcomputer for storing a control program to control said microcomputer;

write control means surface mounted on said circuit board and responsive to a write control signal for controlling said program memory means to permit writing of the control program into said program memory means;

input means surface mounted on said circuit board and connected to a second one of said input terminals for receiving from a source, external to said circuit board, the control program to be written into said program memory means when said program memory means is under control of said write control means; and

isolation means mounted on said circuit board, connected to said microcomputer, to said first one of said input terminals and to said one of said output terminals, and responsive to the write control signal, for electrically isolating said microcomputer from the sensor and the actuator when said write control means is controlling said program memory means, to inhibit input of signals from the sensor and output of signals to the actuator during writing of the control program into said program memory means.

18. A control apparatus according to claim 17, wherein said microcomputer is adapted for operation in one of a write mode, for writing the control program into said program memory means, and a normal operation mode, for applying output signals to the actuator to control the operating condition of the engine, and wherein said write control means is further responsive to the write control signal to cause said microcomputer to operate in a selected one of the write mode and the normal operation mode.

19. A control apparatus according to claim 17, wherein said program memory means is a programmable read only memory.

20. A control apparatus according to claim 17, wherein said one of said output terminals is adapted for connection to an ignition coil of the internal combustion engine.

21. A control apparatus according to claim 17, wherein said one of said output terminals is adapted for connection to a fuel injector of the internal combustion engine.

22. A control apparatus according to claim 17, wherein said isolation means comprises a first buffer circuit coupling said first one of said input terminals to said microcomputer and a second buffer circuit coupling said microcomputer to said one of said output terminals, each buffer circuit being responsive to the write control signal to assume a first state inhibiting passage of signals through that buffer circuit and responsive to absence of the write control signal to assume a second state permitting passage of signals through that buffer circuit.

23. A control apparatus according to claim 17, wherein said write control means comprises switching means responsive to the write control signal for applying a voltage signal to said program memory means, and said program memory means is responsive to the voltage signal to permit writing of the control program in said program memory means.

24. A control apparatus for controlling an internal combustion engine of an automobile, said control apparatus comprising:

a circuit board having a plurality of input terminals and a plurality of output terminals;

a single chip microcomputer sealed in plastic, surface mounted on said circuit board, and having an input and an output, said input adapted for connection via a first one of said input terminals to a sensor, external to said circuit board, which senses an operating condition of the automobile, said output adapted for connection via one of said output terminals to an actuator, external to said circuit board, for controlling an operating condition of said internal combustion engine in accordance with the sensed operating condition;

program memory means in said microcomputer for storing a control program to control said microcomputer;

write control means surface mounted on said circuit board and responsive to a write control signal from said microcomputer, for controlling said program memory means to permit writing of the control program into said program memory means;

first input means surface mounted on said circuit board and connected to a second one of said input terminals for serially receiving from a source, external to said circuit board, a control program to be written into said program memory means when said program memory means is under control of said write control means;

isolation means mounted on said circuit board, connected to said microcomputer, to said first one of said input terminals, and to said one of said output terminals, and responsive to the write control signal, for electrically isolating said microcomputer from the sensor and the actuator when said write control means is controlling said program memory means, to inhibit input of signals from the sensor and output of signals to the actuator during writing of the control program into said program memory means;

serial communication interface means in said microcomputer for serially receiving the control program from said first input means; and

second input means surface mounted on said circuit board and connected to a third one of said input terminals for receiving from a source, external to said circuit board, a write mode signal, wherein;

said microcomputer is responsive to the write mode signal to apply the write control signal to said write control means; and

said write control means is responsive to the write control signal from said microcomputer, for controlling said program memory means to permit writing of the control program received by said serial communication interface means into said program memory means.

25. A control apparatus according to claim 24, wherein said microcomputer is adapted for operation in one of a write mode, for writing the control program received by said serial communication interface means into said program memory means, and a normal operation mode, for applying output signals to the actuator to control the operating condition of the engine, and wherein said write control means is further responsive to the write control signal from said microcomputer, to cause said microcomputer to operate in a selected one of the write mode and the normal operation mode.

26. A control apparatus according to claim 24, wherein said program memory means is a programmable read only memory.

27. A control apparatus according to claim 24, wherein said one of said output terminals is adapted for connection to an ignition coil of the internal combustion engine.

28. A control apparatus according to claim 24, wherein said one of said output terminals is adapted for connection to a fuel injector of the internal combustion engine.

29. A control apparatus according to claim 24, wherein said isolation means comprises a first buffer circuit coupling said first one of said input terminals to said microcomputer and a second buffer circuit coupling said microcomputer to said one of said output terminals, each buffer circuit being responsive to the write control signal to assume a first state inhibiting passage of signals through that buffer circuit and responsive to absence of the write control signal to assume a second state permitting passage of signals through that buffer circuit.

30. A control apparatus according to claim 24, wherein said write control means comprises switching means responsive to the write control signal for applying a voltage signal to said program memory means, and said program memory means is responsive to the voltage signal to permit writing of the control program in said program memory means.