Automobile controller

Details Automobile controller Automobile controller

1998-12-04

2001-01-30

Yoo, Do Hyun (Department: 2759)

Electrical computers and digital processing systems: memory

Storage accessing and control

Specific memory composition

C365S185240, C365S185330

Reexamination Certificate

active

06182190

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automobile controller for engine control or transmission control for arithmetic-processing a controlled variable in accordance with a control program, particularly to a microcomputer-mounted automobile controller making a memory storing a control program erasable while the memory is set to the controller.
2. Description of Related Art
An automobile controller is exposed to severe conditions such as temperature change and vibration. Particularly, for engine control, a socket cannot be used to set a microcomputer storing a control program or a ROM (Read Only Memory) because of improving the vibration resistance. Therefore, a program is written in a ROM (Read Only Memory) by an exclusive unit before a controller is assembled and directly soldered to a substrate.
BRIEF SUMMARY OF THE INVENTION
Object of the Invention
In the case of a conventional controller, a microcomputer or ROM must be directly soldered to a substrate because of the above reason. In this case, the following problem occurs.
In the case of an engine controller, control programs must be changed sometimes due to mismatch of control data due to the difference between engines under mass production. In this case, the prior art requires temporarily removing a microcomputer or ROM from a substrate to rewrite a control program and thereafter, soldering the microcomputer or ROM to the substrate again. Therefore, there are problems that a lot of man-hours are required and the reliability of a soldered portion is deteriorated.
Moreover, when a device storing a control program cannot be erased or rewritten, it is necessary to disuse the device removed from a substrate and replace the device with a new one. Therefore, there is a problem that the cost increases.
To solve these problems, the official gazette of Japanese Patent Laid-Open No. 8-203288 discloses a controller using an EEPROM (Electrically Erasable Programmable Read Only Memory) which is one of electrically erasable nonvolatile memories and built in a microcomputer to replace the contents of the nonvolatile memory with a new program while the memory is set to a printed circuit board.
FIG. 6
is a block diagram of the invention disclosed in the official gazette of Japanese Patent Laid-Open No. 8-203288. To set a microcomputer (
1
-
2
) to the rewriting mode, it is necessary to supply a VPP power supply (
1
-
12
) serving as a rewriting power supply and a plurality of interface terminals (
1
-
5
) serving as mode-setting related terminals to a user board (
1
-
1
) serving as a controller from a writing jig (
1
-
8
) serving as an external unit.
Moreover, the block diagram exclusively requires a power supply output terminal (
1
-
18
) for protecting a microcomputer. Therefore, a harness and many connector terminals for connecting the user board (
1
-
1
) with the writing jig (
1
-
8
) are required. Thus, problems occur that a harness is complicated, the number of connector terminals increases, and a board increases in size and weight.
Therefore, to apply an EEPROM to an automobile controller, because the EEPROM is used for a plurality of controllers (for engine control, transmission control, and brake control), a harness is further complicated, fuel consumption and exhaust gas are increased due to increase in weight, the cost is increased, and the automobile controller cannot be mounted on an automobile due to restriction of space in the worst case.
The present invention is made to solve the above problems and its object is to provide an automobile controller capable of setting a microcomputer to the rewriting mode by supplying only a rewriting power supply.
Summary of the Invention
The automobile controller of the invention of claim
1
comprises a microcomputer for performing control processing by accessing an electrically erasable nonvolatile memory storing a control program and rewriting-signal generation means for generating a signal for setting the mode-setting related terminal of the microcomputer to the rewriting mode in accordance with a rewriting program of a built-in nonvolatile memory.
In the case of the automobile controller of the invention of claim
2
, rewriting-signal generation means comprises an external unit storing a rewriting program and a rewriting voltage source for generating a rewriting voltage in accordance with the rewriting program and a logic circuit for generating a signal for setting the mode-setting related terminal of a microcomputer to the rewriting mode in accordance with the rewriting voltage generated by the external unit.
In the case of the automobile controller of the invention of claim
3
, the input circuit of a rewriting voltage source is provided with voltage confirmation means for confirming the power supply voltage of a microcomputer with an external unit.
In the case of the automobile controller of the invention of claim
4
, rewriting-signal generation means comprises an external unit storing a rewriting program and a rewrite-enable signal source for generating a rewrite-enable logic level signal in accordance with the rewriting program and a logic circuit for generating a signal for setting the mode-setting related terminal of a microcomputer to the rewriting mode in accordance with the rewrite-enable logic level signal generated by the external unit.
In the case of the automobile controller of the invention of claim
5
, a nonvolatile memory is provided for the outside of a microcomputer through bus connection and the nonvolatile memory is rewritten by setting the microcomputer to the rewriting mode.


REFERENCES:
patent: 5581503 (1996-12-01), Matsubara et al.
patent: 5687345 (1997-11-01), Matsubara et al.
patent: 5844843 (1998-12-01), Matsubara et al.
patent: 8-203288 (1996-08-01), None

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