12.3.4 Operation During Code-Protect and Write-Protect
DFM has its own code-protect bits in the Configuration Words. In-Circuit Serial Programming read and write operations are disabled when code protection is enabled. However, internal reads operate normally. Internal writes operate normally provided that write protection is not enabled.
If the DFM is write-protected or if NVMADR points at an invalid address location, the WR bit is cleared without any effect. NVMERR is signaled in this scenario.