Hardware control path redundancy for functional safety of peripherals

Abstract

A circuit includes a primary register region and a primary shadow register; a secondary register region and a secondary shadow register; and a safety controller having multiple states. The safety controller transitions to a first write state when a first write signal to write a first value to the primary register region is detected, and copies the first value written to the primary register region to the primary shadow register; transitions to a second write state when a second write signal to write a second value to the secondary register region is detected within a set amount of time of detection of the first write signal, and in the second write state, copies the second value written to the secondary register region to the secondary shadow register; transitions to a compare state to receive a comparison signal indicating whether the first value is the same as the second value; and transitions to an update state when the first value is the same as the second value.