Register Summary
Address
($FF)
..
($9E)
($9D)
($9C)
($9B)
($9A)
($99)
($98)
($97)
($96)
($95)
($94)
($93)
($92)
($91)
($90)
($8F)
($8E)
($8D)
($8C)
($8B)
($8A)
($89)
($88)
($87)
($86)
($85)
($84)
($83)
($82)
($81)
($80)
($7F)
($7E)
($7D)
($7C)
($7B)
($7A)
($79)
($78)
($77)
($76)
($75)
($74)
($73)
($72)
($71)
($70)
($6F)
($6E)
($6D)
($6C)
($6B)
($6A)
($69)
($68)
($67)
($66)
($65)
($64)
($63)
($62)
Name
Reserved
Reserved
Reserved
UCSR1C
UDR1
UCSR1A
UCSR1B
UBRR1L
UBRR1H
Reserved
Reserved
UCSR0C
Reserved
Reserved
Reserved
Reserved
UBRR0H
Reserved
Reserved
Reserved
TCCR3C
TCCR3A
TCCR3B
TCNT3H
TCNT3L
OCR3AH
OCR3AL
OCR3BH
OCR3BL
OCR3CH
OCR3CL
ICR3H
ICR3L
Reserved
Reserved
ETIMSK
ETIFR
Reserved
TCCR1C
OCR1CH
OCR1CL
Reserved
Reserved
Reserved
TWCR
TWDR
TWAR
TWSR
TWBR
OSCCAL
Reserved
XMCRA
XMCRB
Reserved
EICRA
Reserved
SPMCSR
Reserved
Reserved
PORTG
DDRG
PING
PORTF
Bit 7
–
–
–
–
RXC1
RXCIE1
–
–
–
–
–
–
–
–
–
–
–
–
FOC3A
COM3A1
ICNC3
Bit 6
–
–
–
UMSEL1
TXC1
TXCIE1
–
–
–
UMSEL0
–
–
–
–
–
–
–
–
FOC3B
COM3A0
ICES3
Bit 5
–
–
–
UPM11
UDRE1
UDRIE1
–
–
–
UPM01
–
–
–
–
–
–
–
–
FOC3C
COM3B1
–
Bit 4
–
–
–
UPM10
FE1
RXEN1
–
–
–
UPM00
–
–
–
–
–
–
–
–
–
COM3B0
WGM33
Bit 3
–
–
–
USBS1
DOR1
TXEN1
Bit 2
–
–
–
UCSZ11
UPE1
UCSZ12
Bit 1
–
–
–
UCSZ10
U2X1
RXB81
Bit 0
–
–
–
UCPOL1
MPCM1
TXB81
Page
192
190
190
191
194
194
USART1 I/O Data Register
USART1 Baud Rate Register Low
USART1 Baud Rate Register High
–
–
USBS0
–
–
–
–
–
–
–
–
COM3C1
WGM32
–
–
UCSZ01
–
–
–
–
–
–
–
–
COM3C0
CS32
–
–
UCSZ00
–
–
–
–
–
–
–
–
WGM31
CS31
–
–
UCPOL0
–
–
–
–
192
USART0 Baud Rate Register High
–
–
–
–
WGM30
CS30
194
137
133
136
138
138
138
138
139
139
139
139
139
139
Timer/Counter3 – Counter Register High Byte
Timer/Counter3 – Counter Register Low Byte
Timer/Counter3 – Output Compare Register A High Byte
Timer/Counter3 – Output Compare Register A Low Byte
Timer/Counter3 – Output Compare Register B High Byte
Timer/Counter3 – Output Compare Register B Low Byte
Timer/Counter3 – Output Compare Register C High Byte
Timer/Counter3 – Output Compare Register C Low Byte
Timer/Counter3 – Input Capture Register High Byte
Timer/Counter3 – Input Capture Register Low Byte
–
–
–
–
–
FOC1A
–
–
–
–
–
FOC1B
–
–
TICIE3
ICF3
–
FOC1C
–
–
OCIE3A
OCF3A
–
–
–
–
OCIE3B
OCF3B
–
–
–
–
TOIE3
TOV3
–
–
–
–
OCIE3C
OCF3C
–
–
–
–
OCIE1C
OCF1C
–
–
140
141
137
138
138
Timer/Counter1 – Output Compare Register C High Byte
Timer/Counter1 – Output Compare Register C Low Byte
–
–
–
TWINT
TWA6
TWS7
–
–
–
TWEA
TWA5
TWS6
–
–
–
TWSTA
TWA4
TWS5
–
–
–
TWSTO
TWA3
TWS4
–
–
–
TWWC
TWA2
TWS3
–
–
–
TWEN
TWA1
–
–
–
–
–
TWA0
TWPS1
–
–
–
TWIE
TWGCE
TWPS0
207
209
209
208
207
41
Two-wire Serial Interface Data Register
Two-wire Serial Interface Bit Rate Register
Oscillator Calibration Register
–
–
XMBK
–
ISC31
–
SPMIE
–
–
–
–
–
PORTF7
–
SRL2
–
–
ISC30
–
RWWSB
–
–
–
–
–
PORTF6
–
SRL1
–
–
ISC21
–
–
–
–
–
–
–
PORTF5
–
SRL0
–
–
ISC20
–
RWWSRE
–
–
PORTG4
DDG4
PING4
PORTF4
–
SRW01
–
–
ISC11
–
BLBSET
–
–
PORTG3
DDG3
PING3
PORTF3
–
SRW00
XMM2
–
ISC10
–
PGWRT
–
–
PORTG2
DDG2
PING2
PORTF2
–
SRW11
XMM1
–
ISC01
–
PGERS
–
–
PORTG1
DDG1
PING1
PORTF1
XMM0
–
ISC00
–
SPMEN
–
–
PORTG0
DDG0
PING0
PORTF0
–
31
33
89
280
88
88
88
87
8
ATmega128
2467OS–AVR–10/06