Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
(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)
(0x7F)
(0x7E)
(0x7D)
(0x7C)
(0x7B)
(0x7A)
TWAMR
TWCR
TWAM6
TWINT
TWAM5
TWEA
TWAM4
TWSTA
TWAM3
TWSTO
TWAM2
TWWC
TWAM1
TWEN
TWAM0
–
–
237
235
237
237
236
235
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
–
160
Reserved
OCR2B
Timer/Counter2 Output Compare Register B
Timer/Counter2 Output Compare Register A
Timer/Counter2 (8-bit)
159
159
159
158
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
155
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
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
136
136
135
135
ICR1L
TCNT1H
TCNT1L
Reserved
TCCR1C
TCCR1B
TCCR1A
DIDR1
Timer/Counter1 - Counter Register Low Byte
–
FOC1A
ICNC1
COM1A1
–
–
FOC1B
ICES1
COM1A0
–
–
–
–
–
–
–
–
–
–
–
–
–
135
134
132
241
257
–
COM1B1
–
WGM13
WGM12
CS12
–
CS11
WGM11
AIN1D
ADC1D
–
CS10
WGM10
AIN0D
ADC0D
–
COM1B0
–
–
–
–
DIDR0
–
–
ADC5D
–
ADC4D
ADC3D
–
ADC2D
–
Reserved
ADMUX
–
–
–
–
REFS1
–
REFS0
ACME
ADSC
ADLAR
–
MUX3
–
MUX2
ADTS2
ADPS2
MUX1
ADTS1
ADPS1
MUX0
ADTS0
ADPS0
254
257
255
ADCSRB
ADCSRA
–
ADEN
ADATE
ADIF
ADIE
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET SUMMARY]
9
8271GS–AVR–02/2013
MICROCHIP [ MICROCHIP ]
