ATmega48PA/88PA/168PA/328P
Address
(0xC1)
(0xC0)
(0xBF)
(0xBE)
(0xBD)
(0xBC)
(0xBB)
(0xBA)
(0xB9)
(0xB8)
(0xB7)
(0xB6)
(0xB5)
(0xB4)
(0xB3)
(0xB2)
(0xB1)
(0xB0)
(0xAF)
(0xAE)
(0xAD)
(0xAC)
(0xAB)
(0xAA)
(0xA9)
(0xA8)
(0xA7)
(0xA6)
(0xA5)
(0xA4)
(0xA3)
(0xA2)
(0xA1)
(0xA0)
(0x9F)
(0x9E)
(0x9D)
(0x9C)
(0x9B)
(0x9A)
(0x99)
(0x98)
(0x97)
(0x96)
(0x95)
(0x94)
(0x93)
(0x92)
(0x91)
(0x90)
(0x8F)
(0x8E)
(0x8D)
(0x8C)
(0x8B)
(0x8A)
(0x89)
(0x88)
(0x87)
(0x86)
(0x85)
(0x84)
(0x83)
(0x82)
(0x81)
(0x80)
Name
UCSR0B
UCSR0A
Reserved
Reserved
TWAMR
TWCR
TWDR
TWAR
TWSR
TWBR
Reserved
ASSR
Reserved
OCR2B
OCR2A
TCNT2
TCCR2B
TCCR2A
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
OCR1BH
OCR1BL
OCR1AH
OCR1AL
ICR1H
ICR1L
TCNT1H
TCNT1L
Reserved
TCCR1C
TCCR1B
TCCR1A
Bit 7
RXCIE0
RXC0
–
–
TWAM6
TWINT
TWA6
TWS7
–
–
–
FOC2A
COM2A1
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
FOC1A
ICNC1
COM1A1
Bit 6
TXCIE0
TXC0
–
–
TWAM5
TWEA
TWA5
TWS6
EXCLK
–
FOC2B
COM2A0
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
FOC1B
ICES1
COM1A0
Bit 5
Bit 4
Bit 3
Bit 2
UDRIE0
RXEN0
TXEN0
UCSZ02
UDRE0
FE0
DOR0
UPE0
–
–
–
–
–
–
–
–
TWAM4
TWAM3
TWAM2
TWAM1
TWSTA
TWSTO
TWWC
TWEN
2-wire Serial Interface Data Register
TWA4
TWA3
TWA2
TWA1
TWS5
TWS4
TWS3
–
2-wire Serial Interface Bit Rate Register
–
–
–
–
AS2
TCN2UB
OCR2AUB
OCR2BUB
–
–
–
–
Timer/Counter2 Output Compare Register B
Timer/Counter2 Output Compare Register A
Timer/Counter2 (8-bit)
–
–
WGM22
CS22
COM2B1
COM2B0
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
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–
–
–
–
–
–
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–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
Timer/Counter1 - Output Compare Register B High Byte
Timer/Counter1 - Output Compare Register B Low Byte
Timer/Counter1 - Output Compare Register A High Byte
Timer/Counter1 - Output Compare Register A Low Byte
Timer/Counter1 - Input Capture Register High Byte
Timer/Counter1 - Input Capture Register Low Byte
Timer/Counter1 - Counter Register High Byte
Timer/Counter1 - Counter Register Low Byte
–
–
–
–
–
–
–
–
–
WGM13
WGM12
CS12
COM1B1
COM1B0
–
–
Bit 1
RXB80
U2X0
–
–
TWAM0
–
TWA0
TWPS1
–
TCR2AUB
–
CS21
WGM21
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
CS11
WGM11
Bit 0
TXB80
MPCM0
–
–
–
TWIE
TWGCE
TWPS0
–
TCR2BUB
–
CS20
WGM20
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
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–
–
–
CS10
WGM10
8161DS–AVR–10/09
Page
190
189
239
236
238
239
238
236
158
156
156
156
155
152
132
132
132
132
133
133
132
132
131
130
128
9