Rainbow Electronics ATmega128RFA1 - Manual (Page 23)

23
8266A-MCU Wireless-12/09
ATmega128RFA1
8.4 EEPROM Register Description
8.4.1 EEARH – EEPROM Address Register High Byte
Bit 7 6 5 4 3 2 1 0
$22 ($42) Res3 Res2 Res1 Res0 EEAR11 EEAR10 EEAR9 EEAR8 EEARH
Read/Write R R R R RW RW RW RW
Initial Value 0 0 0 0 X X X X
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.
• Bit 7:4 – Res3:0 - Reserved
• Bit 3:0 – EEAR11:8 - EEPROM Address
8.4.2 EEARL – EEPROM Address Register Low Byte
Bit 7 6 5 4 3 2 1 0
$21 ($41) EEAR7 EEAR6 EEAR5 EEAR4 EEAR3 EEAR2 EEAR1 EEAR0 EEARL
Read/Write RW RW RW RW RW RW RW RW
Initial Value X X X X X X X X
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.
• Bit 7:0 – EEAR7:0 - EEPROM Address
8.4.3 EEDR – EEPROM Data Register
Bit 7 6 5 4 3 2 1 0
$20 ($40) EEDR7:0 EEDR
Read/Write RW RW RW RW RW RW RW RW
Initial Value 0 0 0 0 0 0 0 0
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.
• Bit 7:0 – EEDR7:0 - EEPROM Data