Register Summary
Address
$3F ($5F)
$3E ($5E)
$3D ($5D)
$3C ($5C)
$3B ($5B)
$3A ($5A)
$39 ($59)
$38 ($58)
$37 ($57)
$36 ($56)
$35 ($55)
$34 ($54)
$33 ($53)
$32 ($52)
$31
(1)
($51)
(1)
$30 ($50)
$2F ($4F)
$2E ($4E)
$2D ($4D)
$2C ($4C)
$2B ($4B)
$2A ($4A)
$29 ($49)
$28 ($48)
$27 ($47)
$26 ($46)
$25 ($45)
$24 ($44)
$23 ($43)
$22 ($42)
$21 ($41)
$20
(2)
($40)
(2)
$1F ($3F)
$1E ($3E)
$1D ($3D)
$1C ($3C)
$1B ($3B)
$1A ($3A)
$19 ($39)
$18 ($38)
$17 ($37)
$16 ($36)
$15 ($35)
$14 ($34)
$13 ($33)
$12 ($32)
$11 ($31)
$10 ($30)
$0F ($2F)
$0E ($2E)
$0D ($2D)
$0C ($2C)
$0B ($2B)
$0A ($2A)
$09 ($29)
$08 ($28)
$07 ($27)
$06 ($26)
$05 ($25)
$04 ($24)
$03 ($23)
$02 ($22)
Name
SREG
SPH
SPL
OCR0
GICR
GIFR
TIMSK
TIFR
SPMCR
TWCR
MCUCR
MCUCSR
TCCR0
TCNT0
OSCCAL
OCDR
SFIOR
TCCR1A
TCCR1B
TCNT1H
TCNT1L
OCR1AH
OCR1AL
OCR1BH
OCR1BL
ICR1H
ICR1L
TCCR2
TCNT2
OCR2
ASSR
WDTCR
UBRRH
UCSRC
EEARH
EEARL
EEDR
EECR
PORTA
DDRA
PINA
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
–
Bit 6
T
–
Bit 5
H
–
Bit 4
S
–
SP4
–
–
OCIE1A
OCF1A
RWWSRE
TWSTO
SM0
JTRF
COM00
Bit 3
V
–
SP3
–
–
OCIE1B
OCF1B
BLBSET
TWWC
ISC11
WDRF
WGM01
Bit 2
N
SP10
SP2
–
–
TOIE1
TOV1
PGWRT
TWEN
ISC10
BORF
CS02
Bit 1
Z
SP9
SP1
IVSEL
–
OCIE0
OCF0
PGERS
–
ISC01
EXTRF
CS01
Bit 0
C
SP8
SP0
IVCE
–
TOIE0
TOV0
SPMEN
TWIE
ISC00
PORF
CS00
Page
7
10
10
83
46, 67
68
83, 114, 132
84, 115, 132
250
178
30, 66
39, 67, 229
81
83
28
225
SP7
SP6
SP5
Timer/Counter0 Output Compare Register
INT1
INTF1
OCIE2
OCF2
SPMIE
TWINT
SM2
JTD
FOC0
INT0
INTF0
TOIE2
TOV2
RWWSB
TWEA
SE
ISC2
WGM00
INT2
INTF2
TICIE1
ICF1
–
TWSTA
SM1
–
COM01
Timer/Counter0 (8 Bits)
Oscillator Calibration Register
On-Chip Debug Register
ADTS2
COM1A1
ICNC1
ADTS1
COM1A0
ICES1
ADTS0
COM1B1
–
–
COM1B0
WGM13
ACME
FOC1A
WGM12
PUD
FOC1B
CS12
PSR2
WGM11
CS11
PSR10
WGM10
CS10
55,86,133,199,219
109
112
113
113
113
113
113
113
114
114
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
–
–
–
–
UMSEL
–
–
–
–
UPM1
–
–
WDTOE
–
UPM0
–
USBS
–
–
AS2
WDE
TCN2UB
WDP2
UCSZ1
OCR2UB
WDP1
UBRR[11:8]
UCSZ0
–
UCPOL
EEAR8
TCR2UB
WDP0
127
129
129
130
41
165
164
17
17
17
EEPROM Address Register Low Byte
EEPROM Data Register
–
PORTA7
DDA7
PINA7
PORTB7
DDB7
PINB7
PORTC7
DDC7
PINC7
PORTD7
DDD7
PIND7
SPI Data Register
SPIF
SPIE
RXC
RXCIE
ACD
REFS1
ADEN
WCOL
SPE
TXC
TXCIE
ACBG
REFS0
ADSC
–
DORD
UDRE
UDRIE
ACO
ADLAR
ADATE
–
MSTR
FE
RXEN
ACI
MUX4
ADIF
–
CPOL
DOR
TXEN
ACIE
MUX3
ADIE
–
CPHA
PE
UCSZ2
ACIC
MUX2
ADPS2
–
SPR1
U2X
RXB8
ACIS1
MUX1
ADPS1
SPI2X
SPR0
MPCM
TXB8
ACIS0
MUX0
ADPS0
–
PORTA6
DDA6
PINA6
PORTB6
DDB6
PINB6
PORTC6
DDC6
PINC6
PORTD6
DDD6
PIND6
–
PORTA5
DDA5
PINA5
PORTB5
DDB5
PINB5
PORTC5
DDC5
PINC5
PORTD5
DDD5
PIND5
–
PORTA4
DDA4
PINA4
PORTB4
DDB4
PINB4
PORTC4
DDC4
PINC4
PORTD4
DDD4
PIND4
EERIE
PORTA3
DDA3
PINA3
PORTB3
DDB3
PINB3
PORTC3
DDC3
PINC3
PORTD3
DDD3
PIND3
EEMWE
PORTA2
DDA2
PINA2
PORTB2
DDB2
PINB2
PORTC2
DDC2
PINC2
PORTD2
DDD2
PIND2
EEWE
PORTA1
DDA1
PINA1
PORTB1
DDB1
PINB1
PORTC1
DDC1
PINC1
PORTD1
DDD1
PIND1
EERE
PORTA0
DDA0
PINA0
PORTB0
DDB0
PINB0
PORTC0
DDC0
PINC0
PORTD0
DDD0
PIND0
17
64
64
64
64
64
64
65
65
65
65
65
65
140
140
138
161
162
163
165
200
215
217
218
218
180
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
180
6
ATmega16(L)
2466NS–AVR–10/06
ATMEL [ ATMEL CORPORATION ]
