Program memory code protection is controlled using the CP bit
while data EEPROM memory code protection is controlled using the
CPD bit. When code protection is enabled, all program
memory and Data EEPROM locations read as ‘0’. Further programming is
disabled for the program memory and Data EEPROM until a Bulk Erase operation is
performed on the configuration memory region. Program memory and Data EEPROM can still
be programmed and read during program execution.
The User ID locations and Configuration Bytes can be programmed and read out regardless of the code protection settings.
The only way to disable code protection is to use the Bulk Erase Program Memory command
with bit 4 of the payload set to ‘1’. This will disable code protection
and also erase all the memory locations.