9.9.1 ECC Double-bit Error Detected (DED)

A read from the Flash memory that results in a PFM ECC DED causes the Prefetch module to return a bus exception error to the initiator. If that initiator is the CPU, it recognizes the bus exception error, prevents the instruction from executing, or read data from loading, and generates an exception using the bus exception error vector.

When an ECC DED error occurs, the PFMDED bit (CHESTAT[27]) is set. The exception handling code can, then, check this bit to determine whether the exception was caused by a PFM ECC DED event. This bit must be cleared in software by the exception handler.