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