ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 21

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

8.6
8.6.1
8.6.2
8.6.3
9223B–AVR–09/11
Register Description
EEARH and EEARL – The EEPROM Address Register
EEDR – The EEPROM Data Register
EECR – The EEPROM Control Register
• Bits 15:9] – Reserved
These bits are reserved bits in the Atmel
zero.
• Bits 8:0 – EEAR[8:0]: EEPROM Address
The EEPROM Address Registers – EEARH and EEARL specify the EEPROM address in the
256/512/512/1K bytes EEPROM space. The EEPROM data bytes are addressed linearly
between 0 and 255/511/511/1023. The initial value of EEAR is undefined. A proper value must
be written before the EEPROM may be accessed.
EEAR8 is an unused bit in the Atmel ATmega48PA and must always be written to zero.
• Bits 7:0 – EEDR[7:0]: EEPROM Data
For the EEPROM write operation, the EEDR Register contains the data to be written to the
EEPROM in the address given by the EEAR Register. For the EEPROM read operation, the
EEDR contains the data read out from the EEPROM at the address given by EEAR.
• Bits 7:6 – Reserved
These bits are reserved bits in the Atmel ATmega48PA/88PA/168PA and will always read as
zero.
• Bits 5, 4 – EEPM1 and EEPM0: EEPROM Programming Mode Bits
The EEPROM Programming mode bit setting defines which programming action that will be
triggered when writing EEPE. It is possible to program data in one atomic operation (erase the
old value and program the new value) or to split the Erase and Write operations in two differ-
ent operations. The Programming times for the different modes are shown in
Bit
0x22 (0x42)
0x21 (0x41)
Read/Write
Initial Value
Bit
0x20 (0x40)
Read/Write
Initial Value
Bit
0x1F (0x3F)
Read/Write
Initial Value
Atmel ATmega48PA/88PA/168PA [Preliminary]
EEAR7
MSB
R/W
R/W
15
R
X
R
–
7
0
7
0
7
–
0
EEAR6
R/W
R/W
14
R
X
R
–
6
0
6
0
6
–
0
EEPM1
EEAR5
R/W
R/W
R/W
13
R
X
X
–
5
0
5
0
5
®
EEPM0
EEAR4
ATmega48PA/88PA/168PA and will always read as
R/W
R/W
R/W
12
R
X
4
X
–
4
0
4
0
EEAR3
EERIE
R/W
R/W
R/W
11
R
X
3
0
–
3
0
3
0
EEAR2
EEMPE
R/W
R/W
R/W
10
R
X
–
2
0
2
0
2
0
EEAR1
EEPE
R/W
R/W
R/W
R
X
9
–
1
0
1
0
1
X
EEAR8
EEAR0
Table
EERE
R/W
R/W
LSB
R/W
R/W
X
X
8
0
0
0
0
0
8-1.
EEARH
EEARL
EEDR
EECR
21