12

8271DS–AVR–05/11

ATmega48A/PA/88A/PA/168A/PA/328/P

Note:

1. For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory addresses

should never be written.

2. I/O Registers within the address range 0x00 - 0x1F are directly bit-accessible using the SBI and CBI instructions. In these

registers, the value of single bits can be checked by using the SBIS and SBIC instructions.

3. Some of the Status Flags are cleared by writing a logical one to them. Note that, unlike most other AVRs, the CBI and SBI

instructions will only operate on the specified bit, and can therefore be used on registers containing such Status Flags. The

CBI and SBI instructions work with registers 0x00 to 0x1F only.

4. When using the I/O specific commands IN and OUT, the I/O addresses 0x00 - 0x3F must be used. When addressing I/O

Registers as data space using LD and ST instructions, 0x20 must be added to these addresses. The

ATmega48A/PA/88A/PA/168A/PA/328/P is a complex microcontroller with more peripheral units than can be supported

within the 64 location reserved in Opcode for the IN and OUT instructions. For the Extended I/O space from 0x60 - 0xFF in

SRAM, only the ST/STS/STD and LD/LDS/LDD instructions can be used.

5. Only valid for ATmega88A/88PA/168A/168PA/328/328P.

6. BODS and BODSE only available for picoPower devices ATmega48PA/88PA/168PA/328P

0x1B (0x3B)

PCIFR

–

–

–

–

–

PCIF2

PCIF1

PCIF0

0x1A (0x3A)

Reserved

–

–

–

–

–

–

–

–

0x19 (0x39)

Reserved

–

–

–

–

–

–

–

–

0x18 (0x38)

Reserved

–

–

–

–

–

–

–

–

0x17 (0x37)

TIFR2

–

–

–

–

–

OCF2B

OCF2A

TOV2

165

0x16 (0x36)

TIFR1

–

–ICF1

–

–

OCF1B

OCF1A

TOV1

141

0x15 (0x35)

TIFR0

–

–

–

–

–

OCF0B

OCF0A

TOV0

0x14 (0x34)

Reserved

–

–

–

–

–

–

–

–

0x13 (0x33)

Reserved

–

–

–

–

–

–

–

–

0x12 (0x32)

Reserved

–

–

–

–

–

–

–

–

0x11 (0x31)

Reserved

–

–

–

–

–

–

–

–

0x10 (0x30)

Reserved

–

–

–

–

–

–

–

–

0x0F (0x2F)

Reserved

–

–

–

–

–

–

–

–

0x0E (0x2E)

Reserved

–

–

–

–

–

–

–

–

0x0D (0x2D)

Reserved

–

–

–

–

–

–

–

–

0x0C (0x2C)

Reserved

–

–

–

–

–

–

–

–

0x0B (0x2B)

PORTD

PORTD7

PORTD6

PORTD5

PORTD4

PORTD3

PORTD2

PORTD1

PORTD0

95

0x0A (0x2A)

DDRD

DDD7

DDD6

DDD5

DDD4

DDD3

DDD2

DDD1

DDD0

95

0x09 (0x29)

PIND

PIND7

PIND6

PIND5

PIND4

PIND3

PIND2

PIND1

PIND0

95

0x08 (0x28)

PORTC

–

PORTC6

PORTC5

PORTC4

PORTC3

PORTC2

PORTC1

PORTC0

94

0x07 (0x27)

DDRC

–

DDC6

DDC5

DDC4

DDC3

DDC2

DDC1

DDC0

94

0x06 (0x26)

PINC

–

PINC6

PINC5

PINC4

PINC3

PINC2

PINC1

PINC0

94

0x05 (0x25)

PORTB

PORTB7

PORTB6

PORTB5

PORTB4

PORTB3

PORTB2

PORTB1

PORTB0

94

0x04 (0x24)

DDRB

DDB7

DDB6

DDB5

DDB4

DDB3

DDB2

DDB1

DDB0

94

0x03 (0x23)

PINB

PINB7

PINB6

PINB5

PINB4

PINB3

PINB2

PINB1

PINB0

94

0x02 (0x22)

Reserved

–

–

–

–

–

–

–

–

0x01 (0x21)

Reserved

–

–

–

–

–

–

–

–

0x0 (0x20)

Reserved

–

–

–

–

–

–

–

–

Address

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

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