Electronic control apparatus with defined reset function

Details Electronic control apparatus with defined reset function Electronic control apparatus with defined reset function

1987-10-01

1989-12-19

LaRoche, Eugene R.

Boots, shoes, and leggings

371 12, 3072964, G06F 104, G06F 1100, G05B 1502

Patent

active

048886971

DESCRIPTION:

BRIEF SUMMARY
PRIOR ART

The invention is based on an apparatus for resetting computing devices, microprocessors (.mu.C), single-purpose computers, memories, and the like, which after switching off automatically remain connected for a predetermined period of time to a supply voltage, and the apparatus resets the devices by a resetting pulse.
For the resetting of computing devices, microprocessors, and the like, it is known (US-PS 4 296 338) to generate a resetting signal which reacts substantially immediately when the supply voltage for the computing device or the device drops below a predetermined reference value. In addition to this, an external capacitor is discharged and a second resetting signal (reset signal) is generated until the capacitor has again reached a predetermined load state. The clock oscillator of the microprocessor is accordingly given sufficient time to stabilize itself.
Furthermore, it is known (DE-OS 30 35 896, DE-OS 31 19 117) to generate a reset pulse when the microprocessor is turned on so that it is reset in a defined initial state. However, a problem with this is that reset pulses are not generated, for example, when the computer attains an undefined state because of voltage surges and can no longer continue to operate, or when the clock oscillator of the microprocessor is not yet started at the point in time when a reset pulse is generated when the microprocessor is turned on.
In a particular embodiment form of a microprocessor assigned to a fuel proportioning or fuel injection system, it is provided that the microprocessor itself must cut off its voltage supply, for example, by means of a relay; that is, it is also ensured after the motor vehicle, which is operated by the system, is stopped and turned off that microprocessor-controlled systems in the motor vehicle, for example, injection systems, can still work for a period of time and subsequently turn themselves off (for example, free combustion in the so-called LH-Jetronic). In such microprocessor-controlled systems in motor vehicles, an area in which the present invention also belongs, it is not sufficient, as in the known circuits, to ensure that a reset pulse is fed to the microprocessor when the current supply is interfered with or interrupted, or only when the clock oscillator of the microprocessor has already been started. Faulty operation of the microprocessor (for example, an undefined program run) can also occur during a failure of the microprocessor monitoring (so-called watchdog), which is normally available, and cannot be overcome in the usual manner. since the device, at least the computing device, also still supplies itself with voltage after switching off.
Therefore, the invention has the object of providing a reliable resetting in such a microprocessor-controlled (injection) system, which cuts off its voltage supply itself by means of a relay, for example, when faulty operations of any type occur for whatever reason.


SUMMARY OF THE INVENTION

The invention meets this object by providing an evaluation circuit connected to the terminal of the ignition lock switch of the motor vehicle to produce a reset pulse for the computing devices in dependency on the change in the switching state of the switch, and independently of the connection of a supply voltage to the computing devices. This solution has the advantage that, although the microprocessor-controlled system maintains its voltage in the event of being turned off, that is, does not actually allow itself to be shut off, a resetting is nevertheless possible in the case of an error. Accordingly, it is possible for the driver of a motor vehicle, for example, to produce normal conditions again by means of restarting when there are disturbances in the program run, which can occur when an undefined program run occurs during the driving operation despite the microprocessor monitoring circuit (watchdog). During such disturbances in the program run, it can be safely assumed that the vehicle will run noisily or the engine will die, so that the invention cooperates, as it were, wit

REFERENCES:
patent: 4363092 (1982-12-01), Abo et al.
patent: 4528629 (1985-07-01), Breitling
patent: 4562544 (1985-12-01), Bonitz et al.
patent: 4587939 (1986-05-01), Hemminger et al.
patent: 4625309 (1986-11-01), Nitschke
patent: 4629907 (1986-12-01), Kosak
patent: 4696002 (1987-09-01), Schleupen et al.

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