The Power Management Controller performs the powering up and powering down of the power domains of the processor. The Power Management Controller is a memory-mapped controller. The ARM1136JF-S processor accesses this controller using Strongly-Ordered accesses.
The STANDBYWFI signal can also be used to signal to the Power Management Controller that the ARM1136JF-S processor is ready to have its power state changed. STANDBYWFI is asserted in response to a Wait For Interrupt operation.
The Power Management Controller must not power down any of the processor power domains unless STANDBYWFI is asserted.