Code protection allows the device to be protected from unauthorized access. Internal access to the program memory is unaffected by any code protection setting.
The entire program memory space is protected from external reads and
writes by the CP bit. When CP = 0,
external reads and writes of program memory are inhibited and a read will return all
‘0’s. The CPU can continue to read program
memory, regardless of the protection bit settings. Self-writing the program memory is
dependent upon the write-protection setting.