ATmega325PA Atmel Corporation, ATmega325PA Datasheet - Page 26

• Manufacturer Part Number: ATmega325PA
• Manufacturer: Atmel Corporation

8.6
8.6.1
8.6.2
8.6.3
8285D–AVR–06/11
Register Description
EEARH and EEARL – EEPROM Address Register ATmega165A/ATmega165PA
EEARH and EEARL – EEPROM Address
RegisterATmega325A/325PA/3250A/3250PA/625A/645P/6450A/6450P
EEDR – EEPROM Data Register
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P
• Bits 15:9 – Reserved
These bits are reserved and will always read as zero.
• Bits 8:0 – EEAR8:0: EEPROM Address
The EEPROM Address Registers – EEARH and EEARL specify the EEPROM address in the
512 bytes EEPROM space. The EEPROM data bytes are addressed linearly between 0 and
511. The initial value of EEAR is undefined. A proper value must be written before the EEPROM
may be accessed.
• Bits 15:11 – Reserved
These bits are reserved bits in the
ATmega325A/325PA/3250A/3250PA/645A/645P/6450A/6450P and will always read as zero.
• Bits 10:0 – EEAR10:0: EEPROM Address
The EEPROM Address Registers – EEARH and EEARL specify the EEPROM address in the
1/2K bytes EEPROM space. The EEPROM data bytes are addressed linearly between 0 and
1023/2047. The initial value of EEAR is undefined. A proper value must be written before the
EEPROM may be accessed.
Note:
Bit
0x22 (0x42)
0x21 (0x41)
Read/Write
Initial Value
Bit
0x22 (0x42)
0x21 (0x41)
Read/Write
Initial Value
Bit
0x20 (0x40)
Read/Write
Initial Value
1. EEAR10 is only valid for ATmega645A/ATmega645P/ATmega6450A/ATmega6450P
EEAR7
R/W
15
R
0
X
–
7
EEAR7
MSB
R/W
R/W
15
R
X
–
7
0
7
0
EEAR6
R/W
14
R
X
–
6
0
EEAR6
R/W
R/W
14
R
X
–
6
0
6
0
EEAR5
R/W
13
R
X
–
5
0
EEAR5
R/W
R/W
13
R
X
–
5
0
5
0
EEAR4
R/W
12
R
–
4
0
X
EEAR4
R/W
R/W
12
R
X
–
4
0
4
0
EEAR3
R/W
11
R
X
–
3
0
EEAR3
R/W
R/W
11
R
X
–
3
0
3
0
EEAR10
EEAR2
R/W
R/W
10
X
X
2
EEAR2
R/W
R/W
(1)
10
R
X
–
2
0
2
0
EEAR9
EEAR1
R/W
R/W
9
1
X
X
EEAR1
R/W
R/W
R
X
9
–
1
0
1
0
EEAR8
EEAR0
R/W
R/W
EEAR8
EEAR0
8
0
X
X
LSB
R/W
R/W
R/W
X
X
8
0
0
0
EEARH
EEARL
EEARH
EEARL
EEDR
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