Datasheet

ATtiny2313/V

2543H–AVR–02/05

• Bits 6..0 – EEAR6..0: EEPROM Address

The EEPROM Address Register – EEAR specify the EEPROM address in the 128 bytes

EEPROM space. The EEPROM data bytes are addressed linearly between 0 and 127.

The initial value of EEAR is undefined. A proper value must be written before the

EEPROM may be accessed.

The EEPROM Data Register –

EEDR

• 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.

The EEPROM Control Register

– EECR

• Bits 7..6 – Res: Reserved Bits

These bits are reserved bits in the ATtiny2313 and will always read as zero.

• Bits 5, 4 – EEPM1 and EEPM0: EEPROM Programming 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 opera-

tion (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 Table 1. 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 interrupt when Non-volatile memory is ready for programming.

Bit 76543210

MSB LSB EEDR

Read/Write R/W R/W R/W R/W R/W R/W R/W R/W

Initial Value00000000

Bit 76543210

– – 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 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