Datasheet

PIC16F870/871
DS30569C-page 32  2000-2013 Microchip Technology Inc.
3.10 FLASH Program Memory Write
Protection
The configuration word contains a bit that write protects
the FLASH program memory, called WRT. This bit can
only be accessed when programming the
PIC16F870/871 devices via ICSP. Once write protec-
tion is enabled, only an erase of the entire device will
disable it. When enabled, write protection prevents any
writes to FLASH program memory. Write protection
does not affect program memory reads.
TABLE 3-1: READ/WRITE STATE OF INTERNAL FLASH PROGRAM MEMORY
TABLE 3-2: REGISTERS ASSOCIATED WITH DATA EEPROM/PROGRAM FLASH
Configuration Bits
Memory Location
Internal
Read
Internal
Write
ICSP Read ICSP Write
CP1 CP0 WRT
00x All program memory Yes No No No
010 Unprotected areas Yes No Yes No
010 Protected areas Yes No No No
011 Unprotected areas Yes Yes Yes No
011 Protected areas Yes No No No
100 Unprotected areas Yes No Yes No
100 Protected areas Yes No No No
101 Unprotected areas Yes Yes Yes No
101 Protected areas Yes No No No
110 All program memory Yes No Yes Yes
111 All program memory Yes Yes Yes Yes
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Value on:
POR, BOR
Value on
all other
RESETS
0Bh, 8Bh,
10Bh, 18Bh
INTCON GIE PEIE
T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
10Dh EEADR EEPROM Address Register, Low Byte xxxx xxxx uuuu uuuu
10Fh EEADRH
— — — EEPROM Address, High Byte xxxx xxxx uuuu uuuu
10Ch EEDATA EEPROM Data Register, Low Byte xxxx xxxx uuuu uuuu
10Eh EEDATH
— — EEPROM Data Register, High Byte xxxx xxxx uuuu uuuu
18Ch EECON1 EEPGD
— — — WRERR WREN WR RD x--- x000 x--- u000
18Dh EECON2 EEPROM Control Register2 (not a physical register) — —
Legend: x = unknown, u = unchanged, r = reserved, - = unimplemented, read as '0'.
Shaded cells are not used during FLASH/EEPROM access.
Note 1: These bits are reserved; always maintain these bits clear.