ATMEGA2561V ATMEL [ATMEL Corporation], ATMEGA2561V Datasheet - Page 32

• Manufacturer Part Number: ATMEGA2561V
• Description: 8-bit Microcontroller with 64K/128K/256K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Register Description
EEPROM registers
EEARH and EEARL – The
EEPROM Address Register
EEDR – The EEPROM Data
Register
EECR – The EEPROM Control
Register
32
ATmega640/1280/1281/2560/2561
• Bits 15:12 – Res: Reserved Bits
These bits are reserved bits and will always read as zero.
• Bits 11:0 – EEAR8:0: EEPROM Address
The EEPROM Address Registers – EEARH and EEARL specify the EEPROM address
in the 4K bytes EEPROM space. The EEPROM data bytes are addressed linearly
between 0 and 4096. The initial value of EEAR is undefined. A proper value must be
written before the EEPROM may be accessed.
• Bits 7:0 – EEDR7:0: 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 oper-
ation, the EEDR contains the data read out from the EEPROM at the address given by
EEAR.
• Bits 7:6 – Res: Reserved Bits
These bits are reserved bits 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 opera-
tions in two different operations. The Programming times for the different modes are
shown in Table 6. While EEPE is set, any write to EEPMn will be ignored. During reset,
the EEPMn bits will be reset to 0b00 unless the EEPROM is busy programming.
Bit
0x22 (0x42)
0x21 (0x41)
Read/Write
Initial Value
Bit
0x20 (0x40)
Read/Write
Initial Value
Bit
0x1F (0x3F)
Read/Write
Initial Value
EEAR7
MSB
R/W
R/W
15
R
R
–
7
0
X
7
0
7
–
0
EEAR6
R/W
R/W
14
R
R
–
6
0
X
6
0
6
–
0
EEAR5
EEPM1
R/W
R/W
R/W
13
R
X
X
–
5
0
5
0
5
EEAR4
EEPM0
R/W
R/W
R/W
12
R
X
X
–
4
0
4
0
4
EEAR11
EEAR3
EERIE
R/W
R/W
R/W
R/W
11
3
0
3
0
3
X
X
EEMPE
EEAR10
EEAR2
R/W
R/W
R/W
R/W
2
0
10
2
0
X
X
2
EEAR9
EEAR1
EEPE
R/W
R/W
R/W
R/W
1
0
X
1
X
X
9
1
EERE
EEAR8
EEAR0
LSB
R/W
R/W
R/W
R/W
0
0
0
0
2549K–AVR–01/07
X
X
8
0
EEDR
EEARH
EEARL
EECR