A microcontroller with a built-in self-healing function. A programmable memory stores a normal control routine. A processing unit is arranged to execute the normal control routine in order to provide output data on the output line. A danger signal input line which is connected to a logic unit and dedicated to communicating a danger signal to the logic unit. Processor and logic unit state lines are provided between the processing unit and the logic unit for communicating processor state data from the processing unit to the logic unit and communicating logic unit state data from the logic unit to the processing unit. An interrupt line between the logic unit and the processing unit is dedicated to communicating an interrupt signal from the logic unit to the processing unit.