ATmega48P/88P/168P
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
(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)
UCSR0B
UCSR0A
Reserved
Reserved
TWAMR
TWCR
RXCIE0
RXC0
–
TXCIE0
TXC0
–
UDRIE0
UDRE0
–
RXEN0
FE0
TXEN0
DOR0
–
UCSZ02
UPE0
–
RXB80
TXB80
194
193
U2X0
MPCM0
–
–
–
–
–
–
–
–
–
–
–
TWAM0
–
TWAM6
TWINT
TWAM5
TWEA
TWAM4
TWSTA
TWAM3
TWSTO
TWAM2
TWWC
TWAM1
TWEN
–
242
239
241
242
241
239
TWIE
TWDR
2-wire Serial Interface Data Register
TWAR
TWA6
TWS7
TWA5
TWS6
TWA4
TWS5
TWA3
TWS4
TWA2
TWS3
TWA1
–
TWA0
TWGCE
TWPS0
TWSR
TWPS1
TWBR
2-wire Serial Interface Bit Rate Register
Reserved
ASSR
–
–
–
–
AS2
–
–
TCN2UB
–
–
OCR2AUB
–
–
OCR2BUB
–
–
TCR2AUB
–
–
TCR2BUB
–
EXCLK
–
162
Reserved
OCR2B
Timer/Counter2 Output Compare Register B
Timer/Counter2 Output Compare Register A
Timer/Counter2 (8-bit)
160
160
160
159
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
FOC2A
FOC2B
–
–
WGM22
CS22
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
CS21
CS20
COM2A1
COM2A0
COM2B1
COM2B0
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
WGM21
WGM20
156
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
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
136
136
136
136
137
137
136
136
ICR1L
TCNT1H
TCNT1L
Reserved
TCCR1C
TCCR1B
TCCR1A
Timer/Counter1 - Counter Register Low Byte
–
–
–
–
–
–
–
–
–
–
–
FOC1A
ICNC1
COM1A1
FOC1B
ICES1
COM1A0
–
–
–
–
WGM12
–
135
134
132
WGM13
COM1B0
CS12
–
CS11
WGM11
CS10
WGM10
COM1B1
10
8025MS–AVR–6/11