Register Summary
Address
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)
0x20
(1)
(0x40)
(1)
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)
Name
SREG
SPH
SPL
Reserved
GICR
GIFR
TIMSK
TIFR
SPMCR
TWCR
MCUCR
MCUCSR
TCCR0
TCNT0
OSCCAL
SFIOR
TCCR1A
TCCR1B
TCNT1H
TCNT1L
OCR1AH
OCR1AL
OCR1BH
OCR1BL
ICR1H
ICR1L
TCCR2
TCNT2
OCR2
ASSR
WDTCR
UBRRH
UCSRC
EEARH
EEARL
EEDR
EECR
Reserved
Reserved
Reserved
PORTB
DDRB
PINB
PORTC
DDRC
PINC
PORTD
DDRD
PIND
SPDR
SPSR
SPCR
UDR
UCSRA
UCSRB
UBRRL
ACSR
ADMUX
ADCSRA
ADCH
ADCL
TWDR
TWAR
Bit 7
I
–
SP7
INT1
INTF1
OCIE2
OCF2
SPMIE
TWINT
SE
–
–
Bit 6
T
–
SP6
INT0
INTF0
TOIE2
TOV2
RWWSB
TWEA
SM2
–
–
Bit 5
H
–
SP5
–
–
TICIE1
ICF1
–
TWSTA
SM1
–
–
Bit 4
S
–
SP4
–
–
OCIE1A
OCF1A
RWWSRE
TWSTO
SM0
–
–
Bit 3
V
–
SP3
–
–
OCIE1B
OCF1B
BLBSET
TWWC
ISC11
WDRF
–
Bit 2
N
SP10
SP2
–
–
TOIE1
TOV1
PGWRT
TWEN
ISC10
BORF
CS02
Bit 1
Z
SP9
SP1
IVSEL
–
–
–
PGERS
–
ISC01
EXTRF
CS01
Bit 0
C
SP8
SP0
IVCE
–
TOIE0
TOV0
SPMEN
TWIE
ISC00
PORF
CS00
Page
11
13
13
49, 67
68
72, 102, 122
73, 103, 122
213
171
33, 66
41
72
72
31
Timer/Counter0 (8 Bits)
Oscillator Calibration Register
–
COM1A1
ICNC1
–
COM1A0
ICES1
–
COM1B1
–
–
COM1B0
WGM13
ACME
FOC1A
WGM12
PUD
FOC1B
CS12
PSR2
WGM11
CS11
PSR10
WGM10
CS10
58, 75, 123, 193
97
100
101
101
101
101
101
101
102
102
Timer/Counter1 – Counter Register High byte
Timer/Counter1 – Counter Register Low byte
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
FOC2
WGM20
COM21
COM20
WGM21
CS22
CS21
CS20
Timer/Counter2 (8 Bits)
Timer/Counter2 Output Compare Register
–
–
URSEL
URSEL
–
EEAR7
–
–
–
–
UMSEL
–
EEAR6
–
–
–
–
UPM1
–
EEAR5
–
–
WDCE
–
UPM0
–
EEAR4
–
USBS
–
EEAR3
EERIE
–
EEAR2
EEMWE
AS2
WDE
TCN2UB
WDP2
UCSZ1
OCR2UB
WDP1
UBRR[11:8]
UCSZ0
–
EEAR1
EEWE
UCPOL
EEAR8
EEAR0
EERE
TCR2UB
WDP0
117
119
119
119
43
158
156
20
20
20
20
EEPROM Data Register
PORTB7
DDB7
PINB7
–
–
–
PORTD7
DDD7
PIND7
SPIF
SPIE
RXC
RXCIE
ACD
REFS1
ADEN
PORTB6
DDB6
PINB6
PORTC6
DDC6
PINC6
PORTD6
DDD6
PIND6
WCOL
SPE
TXC
TXCIE
ACBG
REFS0
ADSC
PORTB5
DDB5
PINB5
PORTC5
DDC5
PINC5
PORTD5
DDD5
PIND5
–
DORD
UDRE
UDRIE
ACO
ADLAR
ADFR
PORTB4
DDB4
PINB4
PORTC4
DDC4
PINC4
PORTD4
DDD4
PIND4
–
MSTR
FE
RXEN
ACI
–
ADIF
PORTB3
DDB3
PINB3
PORTC3
DDC3
PINC3
PORTD3
DDD3
PIND3
–
CPOL
DOR
TXEN
ACIE
MUX3
ADIE
PORTB2
DDB2
PINB2
PORTC2
DDC2
PINC2
PORTD2
DDD2
PIND2
–
CPHA
PE
UCSZ2
ACIC
MUX2
ADPS2
PORTB1
DDB1
PINB1
PORTC1
DDC1
PINC1
PORTD1
DDD1
PIND1
–
SPR1
U2X
RXB8
ACIS1
MUX1
ADPS1
PORTB0
DDB0
PINB0
PORTC0
DDC0
PINC0
PORTD0
DDD0
PIND0
SPI2X
SPR0
MPCM
TXB8
ACIS0
MUX0
ADPS0
65
65
65
65
65
65
65
65
65
131
131
129
153
154
155
158
194
205
207
208
208
173
SPI Data Register
USART I/O Data Register
USART Baud Rate Register Low byte
ADC Data Register High byte
ADC Data Register Low byte
Two-wire Serial Interface Data Register
TWA6
TWA5
TWA4
TWA3
TWA2
TWA1
TWA0
TWGCE
174
8
ATmega8(L)
2486QS–AVR–10/06
ATMEL [ ATMEL CORPORATION ]
