6.3.9.4 WLM (Write Lock Mode)

Asserting this bit (WLM = 0) divides the user zone into 8-byte pages. The first byte of each page becomes the write lock byte and defines the locked/unlocked status for each byte in the page. Write access is forbidden to a byte if its associated bit in the write lock byte is set to zero. Bit 7 controls byte 7; bit 6 controls byte 6; and so on. Setting bit 0 to zero locks the write lock byte itself. Enabling Write Lock mode limits write operations to one byte at a time.