Valeo Neiman

Alain Sague

Frederic Saint-Joigny

Gilles Chelard

A method of associating the reception of a reset pulse by a microprocessor with access to a specific subprogram depending on whether the reset pulse is associated with a system incorporating the microprocessor being switched on for the purposes of 'waking up' the microprocessor, or whether it constitutes a request coming from some other unit in the system, the method being wherein it comprises the following steps: on switch-on, causing a logical data item accessible by the microprocessor to change from a first state to a second state only after a certain time interval has elapsed since the switch-on; on each occasion that a reset pulse is received, reading the logical data item before the time interval has elapsed; and depending on whether the logical data item is in its first state or in its second state, branching either to an initialization subprogram appropriate to switch-on, or else to a subprogram appropriate to processing the request.

Method and apparatus for associating the reception of reset pulses by a

A device for monitoring the operation of a microprocessor and capable of generating an error signal whenever the frequency of a signal derived from the microprocessor crosses an upper or a lower frequency threshold comprises: an oscillator periodically producing a monotonically varying voltage and including a threshold circuit, the oscillator generating an error signal when the monotonically varying voltage crosses a threshold, and including a reset input for returning the monotonically varying voltage to level closer to its starting voltage; and a treatment circuit for treating the derived signal and generating pulses on the input at the frequency of the derived signal so long as the frequency is no greater than the upper threshold, otherwise applying no pulse to the input. When pulses are produced at a lower frequency, the time interval between two reset pulses is greater than the time interval required for the monotonically varying voltage to reach the threshold voltage.

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Rueil-Malmaison, France

Alain Sague