Patent ID: 7653837

Claim:
A microcontroller system, comprising: a microcontroller configured to: execute an operation preparation program at each start and under a predefined exceptional condition during operation; change to a normal operation program after the operation preparation program has been executed; and output, under a control of the normal operation program, a normal operation indicating signal; a device that is controllable by the microcontroller, the device corresponding to a controlled device; and a monitoring device for: monitoring whether the microcontroller is executing the normal operation program by reference to the normal operation indicating signal; transferring the controlled device into a secured state if the normal operation indicating signal is absent; and locking the controlled device in the secured state if the normal operation indicating signal is absent over a predefined period of time; wherein the monitoring device: includes a register that is incremented each time the predefined exceptional condition occurs; is configured to lock the controlled device in the secured state if a content of the register reaches a predefined value; and selects the predefined time period after which the secured state is locked when the normal operation indicating signal is absent such that it is longer when the exceptional conditions are present than when the exceptional conditions are absent.