PIC16LF18854 Datasheet, PDF (98/668 Pages) Microchip Technology – C Compiler Optimized RISC Architecture

PIC16(L)F18856/76
4.3 Code Protection
Code protection allows the device to be protected from
unauthorized access. Program memory protection and
data memory are controlled independently. Internal
access to the program memory is unaffected by any
code protection setting.
4.3.1 PROGRAM MEMORY PROTECTION
The entire program memory space is protected from
external reads and writes by the CP bit in Configuration
Words. 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. See Section 4.4 “Write
Protection” for more information.
4.3.2 DATA MEMORY PROTECTION
The entire data EEPROM memory space is protected
from external reads and writes by the CPD bit in the
Configuration Words. When CPD = 0, external reads
and writes of EEPROM memory are inhibited and a
read will return all ‘0’s. The CPU can continue to read
EEPROM memory, regardless of the protection bit
settings.
4.4 Write Protection
Write protection allows the device to be protected from
unintended self-writes. Applications, such as boot
loader software, can be protected while allowing other
regions of the program memory to be modified.
The WRT<1:0> bits in Configuration Words define the
size of the program memory block that is protected.
4.5 User ID
Four memory locations (8000h-8003h) are designated
as ID locations where the user can store checksum or
other code identification numbers. These locations are
readable and writable during normal execution. See
Section 10.4.7 “NVMREG Data EEPROM Memory,
User ID, Device ID and Configuration Word
Access” for more information on accessing these
memory locations. For more information on checksum
calculation, see the “PIC16(L)F188XX Memory
Programming Specification” (DS40001753).
DS40001824A-page 98
Preliminary
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