Datasheet

8.6.4. EEPROM Control Register
When addressing I/O Registers as data space using LD and ST instructions, the provided offset must be
used. When using the I/O specific commands IN and OUT, the offset is reduced by 0x20, resulting in an
I/O address offset within 0x00 - 0x3F.
Name: EECR
Offset: 0x3F
Reset: 0x00
Property: When addressing as I/O Register: address offset is 0x1F
Bit 7 6 5 4 3 2 1 0
EEPM1 EEPM0 EERIE EEMPE EEPE EERE
Access
R/W R/W R/W R/W R/W R/W
Reset x x 0 0 x 0
Bits 5:4 – EEPMn: EEPROM Programming Mode Bits [n = 1:0]
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 operations in two different operations. The
Programming times for the different modes are shown in the table below. 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.
Table 8-1. EEPROM Mode Bits
EEPM[1:0] Programming Time Operation
00 3.4ms Erase and Write in one operation (Atomic Operation)
01 1.8ms Erase Only
10 1.8ms Write Only
11 - Reserved for future use
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 EEPE is
cleared. The interrupt will not be generated during EEPROM write or SPM.
Bit 2 – EEMPE: EEPROM Master Write Enable
The EEMPE bit determines whether writing EEPE to '1' causes the EEPROM to be written.
When EEMPE is '1', setting EEPE within four clock cycles will write data to the EEPROM at the selected
address.
If EEMPE is zero, setting EEPE will have no effect. When EEMPE has been written to '1' by software,
hardware clears the bit to zero after four clock cycles. See the description of the EEPE bit for an
EEPROM write procedure.
Bit 1 – EEPE: EEPROM Write Enable
The EEPROM Write Enable Signal EEPE is the write strobe to the EEPROM. When address and data are
correctly set up, the EEPE bit must be written to '1' to write the value into the EEPROM. The EEMPE bit
Atmel ATmega16M1/32M1/64M1 [DATASHEET]
Atmel-8209F-ATmega16M1/32M1/64M1_Datasheet_Complete-10/2016
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