2 eedr – eeprom data register, 3 eecr – eeprom control register, R the eeprom are given in – Rainbow Electronics ATtiny43U User Manual
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8048B–AVR–03/09
5.6.2
EEDR – EEPROM Data Register
• 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.
5.6.3
EECR – EEPROM Control Register
• Bit 7 – Res: Reserved Bit
These bits are reserved and will always read zero. For compatibility with future AVR devices,
always write this bit to zero. After reading, mask out this bit.
• Bit 6 – Res: Reserved Bit
These bits are reserved and will always read zero.
• Bits 5, 4 – EEPM1 and EEPM0: EEPROM Mode Bits
The EEPROM Programming mode bits 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 different
operations. The Programming times for the different modes are shown in
. 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 3 – EERIE: EEPROM Ready Interrupt Enable
Writing EERIE to one enables the EEPROM Ready Interrupt if the I-bit in SREG is set. Writing
EERIE to zero disables the interrupt. The EEPROM Ready Interrupt generates a constant inter-
rupt when Non-volatile memory is ready for programming.
• Bit 2 – EEMPE: EEPROM Master Program Enable
The EEMPE bit determines whether writing EEPE to one will have effect or not.
Bit
7
6
5
4
3
2
1
0
EEDR7
EEDR6
EEDR5
EEDR4
EEDR3
EEDR2
EEDR1
EEDR0
EEDR
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
Bit
7
6
5
4
3
2
1
0
–
–
EEPM1
EEPM0
EERIE
EEMPE
EEPE
EERE
EECR
Read/Write
R
R
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
X
X
0
0
X
0
Table 5-1.
EEPROM Mode Bits
EEPM1
EEPM0
Programming
Time
Operation
0
0
3.4 ms
Erase and Write in one operation (Atomic Operation)
0
1
1.8 ms
Erase Only
1
0
1.8 ms
Write Only
1
1
–
Reserved for future use