A microcontroller has many miscellaneous logics. The miscellaneous logic can include input/outputs of combinational logic or peripheral devices of the microcontroller, storage devices such as latches, or registers. The miscellaneous logic is coupled to multiple stages of scan cells. The multiple stages...http://www.google.de/patents/US6550031?utm_source=gb-gplus-sharePatent US6550031 - Transparently gathering a chips multiple internal states via scan path and a trigger
