Patent ID: 8117428

Claim:
An apparatus for automatically saving and restoring pad configuration registers implemented in a core power domain, the apparatus comprising: a save and restore logic component implemented in the core power domain and coupled to the pad configuration registers; and a memory instantiated in an always-on power domain and coupled to the save and restore logic component, the save and restore logic component implemented in the core power domain to automatically save the pad configuration registers in the memory in a pad configuration save process before a power supply to the core power domain is switched off and to automatically restore the pad configuration registers from the memory in a pad configuration restore process after the power supply to the core power domain is switched on; wherein the pad configuration save process is started before the power supply to the core power domain is switched off; wherein the pad configuration save process is started by having a start save signal sent from the pad configuration registers to the save and restore logic component before the power supply to the core power domain is switched off.