1.8.1 Activating ICSP Write Inhibit

Note: It is not possible to deactivate ICSP Write Inhibit.

ICSP Write Inhibit is activated by executing a pair of NVMCON Double-Word Programming commands to save two 16-bit activation values in the configuration memory space. The target NVM addresses and values required for activation are shown in Activating ICSP Write Inhibit.

Table 1-5. ICSP™ Write Inhibit Fuse Addresses and Codes
ICSP Write Inhibit Fuse Address	Code Value
0x801028	0x006D63
0x80102C	0x006870

Once both addresses contain their activation values, ICSP Write Inhibit will take permanent effect on the next device Reset. Neither address can be reset, erased or otherwise modified, through any means after being successfully programmed, even if one of the addresses has not been programmed.

Only the lower 16 data bits stored at the activation addresses are evaluated; the upper 8 bits and the second 24-bit word, written by the Double-Word Programming NVMOPx bits, should be ‘0’s. The addresses can be programmed in any order and during separate ICSP/Enhanced ICSP/RTSP sessions, but any attempt to program an incorrect 16-bit value, or use a Row Programming operation to program the values, will be aborted without altering the existing data.