AT90PWM2B-16SE ATMEL [ATMEL Corporation], AT90PWM2B-16SE Datasheet - Page 21

• Manufacturer Part Number: AT90PWM2B-16SE
• Description: 8-bit Microcontroller with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

6.3.3
6.3.4
4317J–AVR–08/10
The EEPROM Data Register – EEDR
The EEPROM Control Register – EECR
• Bits 15..9 – Reserved Bits
These bits are reserved bits in the AT90PWM2/2B/3/3B and will always read as zero.
• Bits 8..0 – EEAR8..0: EEPROM Address
The EEPROM Address Registers – EEARH and EEARL specify the EEPROM address in the
512 bytes EEPROM space. The EEPROM data bytes are addressed linearly between 0 and
511. 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 operation, the
EEDR contains the data read out from the EEPROM at the address given by EEAR.
• Bits 7..6 – Reserved Bits
These bits are reserved bits in the AT90PWM2/2B/3/3B 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 trig-
gered when writing EEWE. 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
EEWE 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 6-1.
Read/Write
Initial Value
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
EEPM1
0
0
1
1
EEPM0
EEAR7
EEDR7
0
1
0
1
EEPROM Mode Bits
R/W
R/W
R
0
X
R
7
7
0
7
–
0
Programming
EEAR6
EEDR6
R/W
R/W
R
X
6
0
R
6
0
6
–
0
3.4 ms
1.8 ms
1.8 ms
Time
–
EEAR5
EEDR5
EEPM1
R/W
R/W
R/W
R
5
0
X
5
0
5
X
Operation
Erase and Write in one operation (Atomic Operation)
Erase Only
Write Only
Reserved for future use
EEAR4
EEDR4
EEPM0
R/W
R/W
R/W
R
X
4
0
4
0
4
X
EEAR3
EEDR3
EERIE
R/W
R/W
R/W
R
3
0
X
3
0
3
0
EEMWE
EEDR2
EEAR2
R/W
R/W
R/W
2
0
R
X
2
0
2
0
AT90PWM2/3/2B/3B
EEDR1
EEAR1
EEWE
R/W
R/W
R/W
1
0
1
X
R
X
1
0
EEDR0
EEAR0
EERE
R/W
R/W
R/W
R/W
0
0
0
0
0
X
X
Table
EEARL
EEDR
EECR
6-1. While
21