Image Number 2 for United States Patent #5828822.
A microcontroller supervision circuit comprising an electronic control capable of causing a high-impedance on at least one external pin upon occurrence of a reset condition. A supervision circuit is coupled to the at least one external pin for detecting the high-impedance condition. Upon detection of the high-impedance condition, a signal is generated to indicate failure of the microcontroller to execute code. The microcontroller is programmed to remove the high-impedance condition when code is properly executed within the microcontroller.