Online Self Tests for Microcontrollers in Safety Related Systems

Nowadays it has become common practice to use microcontrollers in safety related systems. Such systems are deployed to achieve functional safety. The international standard IEC 61508 provides requirements to avoid or reduce the risk caused by these systems. The project SafetyLon aims at enhancing the local operating network (LON) to meet the requirements of IEC 61508. For achieving a defined level of integrity either highly reliable hardware with a low residual error probability has to be used or comprehensive online self tests have to be performed. The chosen standard microcontrollers must perform online self tests in order to detect as much hardware faults of the CPU internals as possible. These tests cover the testing of the volatile and non volatile memory and the CPU. All online self tests have to be tailored to the chosen microcontroller and have to meet the requirements given by IEC 61508.