Register Summary
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
0x3F (0x5F)
0x3E (0x5E)
0x3D (0x5D)
0x3C (0x5C)
0x3B (0x5B)
0x3A (0x5A)
0x39 (0x59)
0x38 (0x58)
0x37 (0x57)
0x36 (0x56)
0x35 (0x55)
0x34 (0x54)
0x33 (0x53)
0x32 (0x52)
0x31 (0x51)
0x30 (0x50)
0x2F (0x4F)
0x2E (0x4E)
0x2D (0x4D)
0x2C (0x4C)
0x2B (0x4B)
0x2A (0x4A)
0x29 (0x49)
0x28 (0x48)
0x27 (0x47)
0x26 (0x46)
0x25 (0x45)
0x24 (0x44)
0x23 (0x43)
0x22 (0x42)
0x21 (0x41)
SREG
SPH
I
–
T
–
H
–
S
–
V
–
N
Z
C
9
SP10
SP2
SP9
SP1
SP8
SP0
11
11
SPL
SP7
SP6
SP5
SP4
SP3
Reserved
GICR
INT1
INTF1
OCIE2
OCF2
SPMIE
TWINT
SE
INT0
INTF0
TOIE2
TOV2
RWWSB
TWEA
SM2
–
–
–
–
–
IVSEL
IVCE
–
47, 65
GIFR
–
TICIE1
ICF1
–
–
–
–
–
66
TIMSK
TIFR
OCIE1A
OCF1A
RWWSRE
TWSTO
SM0
OCIE1B
OCF1B
BLBSET
TWWC
ISC11
WDRF
–
TOIE1
TOV1
PGWRT
TWEN
ISC10
BORF
CS02
TOIE0
TOV0
SPMEN
TWIE
ISC00
PORF
CS00
70, 100, 120
–
71, 101, 120
SPMCR
TWCR
MCUCR
MCUCSR
TCCR0
TCNT0
OSCCAL
SFIOR
TCCR1A
TCCR1B
TCNT1H
TCNT1L
OCR1AH
OCR1AL
OCR1BH
OCR1BL
ICR1H
ICR1L
PGERS
–
210
TWSTA
SM1
–
168
ISC01
EXTRF
CS01
31, 64
–
–
–
39
–
–
–
–
70
Timer/Counter0 (8 Bits)
70
Oscillator Calibration Register
29
–
–
–
COM1B1
–
–
ACME
FOC1A
WGM12
PUD
FOC1B
CS12
PSR2
WGM11
CS11
PSR10
WGM10
CS10
56, 73, 121, 190
COM1A1
ICNC1
COM1A0
ICES1
COM1B0
WGM13
95
98
Timer/Counter1 – Counter Register High byte
Timer/Counter1 – Counter Register Low byte
99
99
Timer/Counter1 – Output Compare Register A High byte
Timer/Counter1 – Output Compare Register A Low byte
Timer/Counter1 – Output Compare Register B High byte
Timer/Counter1 – Output Compare Register B Low byte
Timer/Counter1 – Input Capture Register High byte
Timer/Counter1 – Input Capture Register Low byte
99
99
99
99
100
100
115
117
117
117
41
TCCR2
TCNT2
OCR2
FOC2
WGM20
COM21
COM20
WGM21
CS22
CS21
CS20
Timer/Counter2 (8 Bits)
Timer/Counter2 Output Compare Register
ASSR
–
–
–
–
WDCE
–
AS2
TCN2UB
WDP2
OCR2UB
WDP1
TCR2UB
WDP0
WDTCR
UBRRH
UCSRC
EEARH
EEARL
EEDR
–
–
–
–
–
WDE
URSEL
URSEL
–
UBRR[11:8]
155
153
18
0x20(1) (0x40)(1)
UMSEL
–
UPM1
–
UPM0
–
USBS
–
UCSZ1
–
UCSZ0
–
UCPOL
EEAR8
EEAR0
0x1F (0x3F)
0x1E (0x3E)
0x1D (0x3D)
0x1C (0x3C)
0x1B (0x3B)
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)
EEAR7
EEAR6
EEAR5
EEAR4
EEAR3
EEAR2
EEAR1
18
EEPROM Data Register
18
EECR
–
–
–
–
EERIE
EEMWE
EEWE
EERE
18
Reserved
Reserved
Reserved
PORTB
DDRB
PORTB7
DDB7
PINB7
–
PORTB6
DDB6
PORTB5
DDB5
PORTB4
DDB4
PORTB3
DDB3
PORTB2
DDB2
PORTB1
DDB1
PORTB0
DDB0
63
63
PINB
PINB6
PINB5
PINB4
PINB3
PINB2
PINB1
PINB0
63
PORTC
DDRC
PORTC6
DDC6
PORTC5
DDC5
PORTC4
DDC4
PORTC3
DDC3
PORTC2
DDC2
PORTC1
DDC1
PORTC0
DDC0
63
–
63
PINC
–
PINC6
PORTD6
DDD6
PINC5
PINC4
PINC3
PORTD3
DDD3
PINC2
PORTD2
DDD2
PINC1
PINC0
PORTD0
DDD0
63
PORTD
DDRD
PORTD7
DDD7
PIND7
PORTD5
DDD5
PORTD4
DDD4
PORTD1
DDD1
63
63
PIND
PIND6
PIND5
PIND4
PIND3
PIND2
PIND1
PIND0
63
SPDR
SPI Data Register
128
128
126
150
151
152
155
191
202
204
205
205
170
170
SPSR
SPIF
SPIE
WCOL
SPE
–
–
–
–
–
SPI2X
SPR0
SPCR
DORD
MSTR
CPOL
CPHA
SPR1
UDR
USART I/O Data Register
UCSRA
UCSRB
UBRRL
ACSR
RXC
TXC
UDRE
UDRIE
FE
DOR
PE
U2X
MPCM
TXB8
RXCIE
TXCIE
RXEN
TXEN
UCSZ2
RXB8
USART Baud Rate Register Low byte
ACD
REFS1
ADEN
ACBG
REFS0
ADSC
ACO
ADLAR
ADFR
ACI
–
ACIE
MUX3
ADIE
ACIC
MUX2
ADPS2
ACIS1
MUX1
ADPS1
ACIS0
MUX0
ADPS0
ADMUX
ADCSRA
ADCH
ADIF
ADC Data Register High byte
ADC Data Register Low byte
ADCL
TWDR
TWAR
Two-wire Serial Interface Data Register
TWA6
TWA5
TWA4
TWA3
TWA2
TWA1
TWA0
TWGCE
282
ATmega8(L)
2486M–AVR–12/03
ATMEL [ ATMEL ]
