Datasheet

© 2008 Microchip Technology Inc. DS41249E-page 103
PIC16F785/HV785
14.0 DATA EEPROM MEMORY
The EEPROM data memory is readable and writable
during normal operation (full V
DD range). This memory
is not directly mapped in the register file space.
Instead, it is indirectly addressed through the Special
Function Registers. There are four SFRs used to read
and write this memory:
• EECON1
• EECON2 (not a physically implemented register)
• EEDAT
• EEADR
EEDAT holds the 8-bit data for read/write, and EEADR
holds the address of the EEPROM location being
accessed. The PIC16F785/HV785 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 in
Section 19.0 “Electrical Specifications” for exact
limits.
When the data memory is code-protected, the CPU
may continue to read and write the data EEPROM
memory. The device programmer can no longer access
the data EEPROM data and will read zeroes.
REGISTER 14-1: EEDAT: EEPROM DATA REGISTER
REGISTER 14-2: EEADR: EEPROM ADDRESS REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
EEDAT7 EEDAT6 EEDAT5 EEDAT4 EEDAT3 EEDAT2 EEDAT1 EEDAT0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 EEDATn: Byte Value to Write to or Read From Data EEPROM bits
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
EEADR7 EEADR6 EEADR5 EEADR4 EEADR3 EEADR2 EEADR1 EEADR0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 EEADR: Specifies one of 256 locations for EEPROM Read/Write Operation bits