Datasheet

© 2009 Microchip Technology Inc. DS39761C-page 361
PIC18F2682/2685/4682/4685
TABLE 24-3: SUMMARY OF CODE PROTECTION REGISTERS
24.5.1 PROGRAM MEMORY
CODE PROTECTION
The program memory may be read to or written from
any location using the table read and table write
instructions. The Device ID may be read with table
reads. The Configuration registers may be read and
written with the table read and table write instructions.
In normal execution mode, the CPn bits have no direct
effect. CPn bits inhibit external reads and writes. A
block of user memory may be protected from table
writes if the WRTn Configuration bit is ‘0’. The EBTRn
bits control table reads. For a block of user memory
with the EBTRn bit set to ‘0’, a table read instruction
that executes from within that block is allowed to read.
A table read instruction that executes from a location
outside of that block is not allowed to read and will
result in reading ‘0’s. Figures 24-6 through 24-8
illustrate table write and table read protection.
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
300008h CONFIG5L
— —CP5
(1)
CP4 CP3 CP2 CP1 CP0
300009h CONFIG5H CPD CPB — — — — — —
30000Ah CONFIG6L — —WRT5
(1)
WRT4 WRT3 WRT2 WRT1 WRT0
30000Bh CONFIG6H WRTD WRTB WRTC
— — — — —
30000Ch CONFIG7L — — EBTR5
(1)
EBTR4 EBTR3 EBTR2 EBTR1 EBTR0
30000Dh CONFIG7H — EBTRB — — — — — —
Legend: Shaded cells are unimplemented.
Note 1: Unimplemented in PIC18F2682/4682 devices; maintain this bit set.
Note: Code protection bits may only be written to
a ‘0’ from a ‘1’ state. It is not possible to
write a ‘1’ to a bit in the ‘0’ state. Code
protection bits are only set to ‘1’ by a full
Chip Erase or Block Erase function. The
full Chip Erase and Block Erase functions
can only be initiated via ICSP or an
external programmer.