Error checking of mutually-exclusive control signals

摘要

This error checker determines if more than one set of control signals F1 through FN are on and also flags invalid as opposed to valid situations where none of the control signals F1 to FN are on. To distinguish the invalid from valid situations where none of the control signals F1 to FN are on, an additional control signal X=F1xF2x . . . xFN is generated and then fed with the control signals F1 to FN through a prior art detector which detects when more than one or none of the control signals X and F1 through FN are on.