PIC16F627A Datasheet, PDF (91/168 Pages) Microchip Technology – FLASH-Based 8-Bit CMOS Microcontrollers

PIC16F627A/628A/648A
13.0 DATA EEPROM MEMORY
The EEPROM data memory is readable and writable
during normal operation (full VDD range). This memory
is not directly mapped in the register file space. Instead
it is indirectly addressed through the Special Function
Registers (SFRs). There are four SFRs used to read
and write this memory. These registers are:
• EECON1
• EECON2 (Not a physically implemented register)
• EEDATA
• EEADR
EEDATA holds the 8-bit data for read/write, and
EEADR holds the address of the EEPROM location
being accessed. PIC16F627A/628A devices have 128
bytes of data EEPROM with an address range from 0h
to 7Fh. PIC16F648A device has 256 bytes of data
EEPROM with an address range from 0h to FFh.
The EEPROM data memory allows byte read and write.
A byte write automatically erases the location and
writes the new data (erase before write). The EEPROM
data memory is rated for high erase/write cycles. The
write time is controlled by an on-chip timer. The write-
time will vary with voltage and temperature as well as
from chip to chip. Please refer to AC specifications for
exact limits.
When the device is code protected, the CPU can
continue to read and write the data EEPROM memory.
A device programmer can no longer access
this memory.
Additional information on the Data EEPROM is avail-
able in the PICmicro™ Mid-Range Reference Manual,
(DS33023).
REGISTER 13-1:
EEDATA REGISTER (ADDRESS: 9Ah)
R/W-x R/W-x R/W-x R/W-x
EEDAT7 EEDAT6 EEDAT5 EEDAT4
bit 7
R/W-x
EEDAT3
R/W-x
EEDAT2
R/W-x
EEDAT1
R/W-x
EEDAT0
bit 0
bit 7-0
EEDATn: Byte value to write to or read from Data EEPROM memory location.
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
’1’ = Bit is set
REGISTER 13-2:
EEADR REGISTER (ADDRESS: 9Bh)
R/W-x R/W-x R/W-x R/W-x
EADR7 EADR6 EADR5 EADR4
bit 7
U = Unimplemented bit, read as ‘0’
’0’ = Bit is cleared x = Bit is unknown
R/W-x
EADR3
R/W-x
EADR2
R/W-x
EADR1
R/W-x
EADR0
bit 0
bit 7
bit 6-0
PIC16F627A/628A - Unimplemented Address: Must be set to ‘0’
PIC16F648A - EEADR: Set to ‘1’ specifies top 128 locations (128-256) of EEPROM Read/Write
Operation
EEADR: Specifies one of 128 locations of EEPROM Read/Write Operation
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
’1’ = Bit is set
U = Unimplemented bit, read as ‘0’
’0’ = Bit is cleared x = Bit is unknown
 2002 Microchip Technology Inc.
Preliminary
DS40044A-page 89