Datasheet

PIC16F630/676

8.7 DATA EEPROM OPERATION

DURING CODE PROTECT

Data memory can be code protected by programming

the CPD bit to ‘0’.

When the data memory is code protected, the CPU is

able to read and write data to the Data EEPROM. It is

recommended to code protect the program memory

when code protecting data memory. This prevents

anyone from programming zeroes over the existing

code (which will execute as NOPs) to reach an added

routine, programmed in unused program memory,

which outputs the contents of data memory.

Programming unused locations to ‘0’ will also help

prevent data memory code protection from becoming

breached.

TABLE 8-1: REGISTERS/BITS ASSOCIATED WITH DATA EEPROM

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Value on

POR, BOD

Value on all

other

RESETS

0Ch PIR1 EEIF

ADIF — — CMIF — — TMR1IF 00-- 0--0 00-- 0--0

9Ah EEDATA EEPROM Data Register 0000 0000 0000 0000

9Bh EEADR

— EEPROM Address Register -000 0000 -000 0000

9Ch EECON1

— — — — WRERR WREN WR RD ---- x000 ---- q000

9Dh EECON2

(1)

EEPROM Control Register 2 ---- ---- ---- ----

Legend: x = unknown, u = unchanged, – = unimplemented read as '0', q = value depends upon condition.

Shaded cells are not used by Data EEPROM module.

Note 1: EECON2 is not a physical register.