31.3.12.2 ECC Double Error Detected (INTFLAG.DERR)

When ECC is active (i.e. not OFF/Bypass) and a read from Flash memory results in an ECC DED, the FCR returns a bus error to the initiator. The error is returned in-band with the data and the initiator determines how to handle the corrupted data using the initiator’s bus error exception handler.

For the ECC Double Error Detect (DED), the FCR sets the INTFLAG.DERR bit, thus the Bus Error exception handler can check this bit to determine that a double error has been detected by the ECC. A properly constructed bus error exception handler should be able to decode and report the address that triggered the double bit error. The data is loaded into the read buffer with a DED tag so subsequent reads of the address also causes bus errors.