User ID, Device ID, Configuration Settings Access, DIA and DCI

The NVMADR value determines which NVM address space is accessed. The User IDs and Configuration areas allow read and write access, whereas Device and Revision IDs are limited to read-only.

Reading and writing User ID space is identical to reading and writing PFM space as described in the preceding paragraphs.

Writing to the Configuration bits is performed in the same manner as writing to the Data Flash Memory (DFM). Configuration settings are modified one byte at a time with the NVM Read and Write operations. When a Write operation is performed on a Configuration byte, an erase byte is performed automatically before the new byte is written. Any code protection settings that are not enabled will remain not enabled after the Write operation, unless the new values enable them. However, any code protection settings that are enabled cannot be disabled by a self-write of the configuration space. The user can modify the configuration space by the following steps:
  1. 1.Read the target Configuration byte by setting the NVMADR with the target address.
  2. 2.Retrieve the Configuration byte with the Read operation (NVMCMD = ‘b000).
  3. 3.Modify the Configuration byte in NVMDAT register.
  4. 4.Write the NVMDAT register to the Configuration byte using the Write operation (NVMCMD = ‘b011) and unlock sequence.