Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
0x1A (0x3A)
0x19 (0x39)
0x18 (0x38)
0x17 (0x37)
0x16 (0x36)
0x15 (0x35)
0x14 (0x34)
0x13 (0x33)
0x12 (0x32)
0x11 (0x31)
0x10 (0x30)
0x0F (0x2F)
0x0E (0x2E)
0x0D (0x2D)
0x0C (0x2C)
0x0B (0x2B)
0x0A (0x2A)
0x09 (0x29)
0x08 (0x28)
0x07 (0x27)
0x06 (0x26)
0x05 (0x25)
0x04 (0x24)
0x03 (0x23)
0x02 (0x22)
0x01 (0x21)
0x00 (0x20)
GPIOR2
GPIOR1
Reserved
Reserved
TIFR1
GPIOR27
GPIOR26
GPIOR25
GPIOR24
GPIOR23
GPIOR22
GPIOR21
GPIOR20
page 28
page 28
GPIOR17
GPIOR16
GPIOR15
GPIOR14
GPIOR13
GPIOR12
GPIOR11
GPIOR10
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
ICF1
–
–
OCF1B
OCF0B
–
OCF1A
OCF0A
–
TOV1
TOV0
–
page 134
page 106
TIFR0
–
–
–
–
–
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
PORTE
DDRE
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
PORTE2
DDE2
PINE2
PORTD2
DDD2
PIND2
PORTC2
DDC2
PINC2
PORTB2
DDB2
PINB2
–
PORTE1
DDE1
PINE1
PORTD1
DDD1
PIND1
PORTC1
DDC1
PINC1
PORTB1
DDB1
PINB1
–
PORTE0
DDE0
PINE0
PORTD0
DDD0
PIND0
PORTC0
DDC0
PINC0
PORTB0
DDB0
PINB0
–
page 81
page 81
page 81
page 80
page 80
page 81
page 80
page 80
page 80
page 80
page 80
page 80
–
–
–
–
–
PINE
–
–
–
–
–
PORTD
DDRD
PORTD7
DDD7
PIND7
PORTC7
DDC7
PINC7
PORTB7
DDB7
PINB7
–
PORTD6
DDD6
PIND6
PORTC6
DDC6
PINC6
PORTB6
DDB6
PINB6
–
PORTD5
DDD5
PIND5
PORTC5
DDC5
PINC5
PORTB5
DDB5
PINB5
–
PORTD4
DDD4
PIND4
PORTC4
DDC4
PINC4
PORTB4
DDB4
PINB4
–
PORTD3
DDD3
PIND3
PORTC3
DDC3
PINC3
PORTB3
DDB3
PINB3
–
PIND
PORTC
DDRC
PINC
PORTB
DDRB
PINB
Reserved
Reserved
Reserved
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
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
ATmega16/32/64/M1/C1 is a complex microcontroller with more peripheral units than can be supported within the 64 loca-
tion 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. These registers are only available on ATmega32/64M1. For other products described in this datasheet, these locations are
reserved.
16
ATmega16/32/64/M1/C1
7647DS–AVR–08/08
ATMEL [ ATMEL ]
