| Offset | Name | Bit Pos. | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|---|---|---|---|---|---|---|---|---|---|---|
0x00 ... 0x22 |
Reserved | |||||||||
| 0x23 | PINB | 7:0 | PINB7 | PINB6 | PINB5 | PINB4 | PINB3 | PINB2 | PINB1 | PINB0 |
| 0x24 | DDRB | 7:0 | DDRB7 | DDRB6 | DDRB5 | DDRB4 | DDRB3 | DDRB2 | DDRB1 | DDRB0 |
| 0x25 | PORTB | 7:0 | PORTB7 | PORTB6 | PORTB5 | PORTB4 | PORTB3 | PORTB2 | PORTB1 | PORTB0 |
| 0x26 | PINC | 7:0 | PINC6 | PINC5 | PINC4 | PINC3 | PINC2 | PINC1 | PINC0 | |
| 0x27 | DDRC | 7:0 | DDRC6 | DDRC5 | DDRC4 | DDRC3 | DDRC2 | DDRC1 | DDRC0 | |
| 0x28 | PORTC | 7:0 | PORTC6 | PORTC5 | PORTC4 | PORTC3 | PORTC2 | PORTC1 | PORTC0 | |
| 0x29 | PIND | 7:0 | PIND7 | PIND6 | PIND5 | PIND4 | PIND3 | PIND2 | PIND1 | PIND0 |
| 0x2A | DDRD | 7:0 | DDRD7 | DDRD6 | DDRD5 | DDRD4 | DDRD3 | DDRD2 | DDRD1 | DDRD0 |
| 0x2B | PORTD | 7:0 | PORTD7 | PORTD6 | PORTD5 | PORTD4 | PORTD3 | PORTD2 | PORTD1 | PORTD0 |
| 0x2C | PINE | 7:0 | PINE3 | PINE2 | PINE1 | PINE0 | ||||
| 0x2D | DDRE | 7:0 | DDRE3 | DDRE2 | DDRE1 | DDRE0 | ||||
| 0x2E | PORTE | 7:0 | PORTE3 | PORTE2 | PORTE1 | PORTE0 | ||||
0x2F ... 0x34 |
Reserved | |||||||||
| 0x35 | TIFR0 | 7:0 | OCF0B | OCF0A | TOV0 | |||||
| 0x36 | TIFR1 | 7:0 | ICF1 | OCF1B | OCF1A | TOV1 | ||||
| 0x37 | TIFR2 | 7:0 | OCF2B | OCF2A | TOV2 | |||||
| 0x38 | TIFR3 | 7:0 | ICF3 | OCF3B | OCF3A | TOV3 | ||||
| 0x39 | TIFR4 | 7:0 | ICF4 | OCF4B | OCF4A | TOV4 | ||||
0x3A |
Reserved | |||||||||
| 0x3B | PCIFR | 7:0 | PCIF3 | PCIF2 | PCIF1 | PCIF0 | ||||
| 0x3C | EIFR | 7:0 | INTF1 | INTF0 | ||||||
| 0x3D | EIMSK | 7:0 | INT1 | INT0 | ||||||
| 0x3E | GPIOR0 | 7:0 | GPIOR0[7:0] | |||||||
| 0x3F | EECR | 7:0 | EEPM[1:0] | EERIE | EEMPE | EEPE | EERE | |||
| 0x40 | EEDR | 7:0 | EEDR[7:0] | |||||||
| 0x41 | EEARL and EEARH | 7:0 | EEAR[7:0] | |||||||
| 15:8 | EEAR[9:8] | |||||||||
| 0x43 | GTCCR | 7:0 | TSM | PSRASY | PSRSYNC | |||||
| 0x44 | TCCR0A | 7:0 | COM0A[1:0] | COM0B [1:0] | WGM0[1:0] | |||||
| 0x45 | TCCR0B | 7:0 | FOC0A | FOC0B | WGM0 [2] | CS0[2:0] | ||||
| 0x46 | TCNT0 | 7:0 | TCNT0[7:0] | |||||||
| 0x47 | OCR0A | 7:0 | OCR0A[7:0] | |||||||
| 0x48 | OCR0B | 7:0 | OCR0B[7:0] | |||||||
0x49 |
Reserved | |||||||||
| 0x4A | GPIOR1 | 7:0 | GPIOR1[7:0] | |||||||
| 0x4B | GPIOR2 | 7:0 | GPIOR2[7:0] | |||||||
| 0x4C | SPCR0 | 7:0 | SPIE0 | SPE0 | DORD0 | MSTR0 | CPOL0 | CPHA0 | SPR0 [1:0] | |
| 0x4D | SPSR0 | 7:0 | SPIF0 | WCOL0 | SPI2X0 | |||||
| 0x4E | SPDR0 | 7:0 | SPID[7:0] | |||||||
0x4F |
Reserved | |||||||||
| 0x50 | ACSR | 7:0 | ACD | ACBG | ACO | ACI | ACIE | ACIC | ACIS [1:0] | |
| 0x51 | DWDR | 7:0 | DWDR[7:0] | |||||||
0x52 |
Reserved | |||||||||
| 0x53 | SMCR | 7:0 | SM[2:0] | SE | ||||||
| 0x54 | MCUSR | 7:0 | WDRF | BORF | EXTRF | PORF | ||||
| 0x55 | MCUCR | 7:0 | BODS | BODSE | PUD | IVSEL | IVCE | |||
0x56 |
Reserved | |||||||||
| 0x57 | SPMCSR | 7:0 | SPMIE | RWWSB | SIGRD | RWWSRE | BLBSET | PGWRT | PGERS | SPMEN |
0x58 ... 0x5C |
Reserved | |||||||||
| 0x5D | SPL and SPH | 7:0 | SP7 | SP6 | SP5 | SP4 | SP3 | SP2 | SP1 | SP0 |
| 15:8 | SP11 | SP10 | SP9 | SP8 | ||||||
| 0x5F | SREG | 7:0 | I | T | H | S | V | N | Z | C |
| 0x60 | WDTCSR | 7:0 | WDIF | WDIE | WDP[3] | WDCE | WDE | WDP[2:0] | ||
| 0x61 | CLKPR | 7:0 | CLKPCE | CLKPS [3:0] | ||||||
| 0x62 | XFDCSR | 7:0 | XFDIF | XFDIE | ||||||
0x63 |
Reserved | |||||||||
| 0x64 | PRR | 7:0 | PRTWI0 | PRTIM2 | PRTIM0 | PRUSART1 | PRTIM1 | PRSPI0 | PRUSART0 | PRADC |
| 0x65 | PRR1 | 7:0 | PRTWI1 | PRPTC | PRTIM4 | PRSPI1 | PRTIM3 | |||
| 0x66 | OSCCAL | 7:0 | CAL [7:0] | |||||||
0x67 |
Reserved | |||||||||
| 0x68 | PCICR | 7:0 | PCIE3 | PCIE2 | PCIE1 | PCIE0 | ||||
| 0x69 | EICRA | 7:0 | ISC1 [1:0] | ISC0 [1:0] | ||||||
0x6A |
Reserved | |||||||||
| 0x6B | PCMSK0 | 7:0 | PCINT[7:0] | |||||||
| 0x6C | PCMSK1 | 7:0 | PCINT[14:8] | |||||||
| 0x6D | PCMSK2 | 7:0 | PCINT[23:16] | |||||||
| 0x6E | TIMSK0 | 7:0 | OCIE0B | OCIE0A | TOIE0 | |||||
| 0x6F | TIMSK1 | 7:0 | ICIE1 | OCIE1B | OCIE1A | TOIE1 | ||||
| 0x70 | TIMSK2 | 7:0 | OCIE2B | OCIE2A | TOIE2 | |||||
| 0x71 | TIMSK3 | 7:0 | ICIE3 | OCIE3B | OCIE3A | TOIE3 | ||||
| 0x72 | TIMSK4 | 7:0 | ICIE4 | OCIE4B | OCIE4A | TOIE4 | ||||
| 0x73 | PCMSK3 | 7:0 | PCINT[27:24] | |||||||
0x74 ... 0x77 |
Reserved | |||||||||
| 0x78 | ADCL and ADCH | 7:0 | ADC[7:0] | |||||||
| 15:8 | ADC[9:8] | |||||||||
| 0x78 | ADCL and ADCH | 7:0 | ADC[1:0] | |||||||
| 15:8 | ADC[9:2] | |||||||||
| 0x7A | ADCSRA | 7:0 | ADEN | ADSC | ADATE | ADIF | ADIE | ADPS [2:0] | ||
| 0x7B | ADCSRB | 7:0 | ACME | ADTS [2:0] | ||||||
| 0x7C | ADMUX | 7:0 | REFS [1:0] | ADLAR | MUX [3:0] | |||||
0x7D |
Reserved | |||||||||
| 0x7E | DIDR0 | 7:0 | ADC7D | ADC6D | ADC5D | ADC4D | ADC3D | ADC2D | ADC1D | ADC0D |
| 0x7F | DIDR1 | 7:0 | AIN1D | AIN0D | ||||||
| 0x80 | TCCR1A | 7:0 | COM1A[1:0] | COM1B[1:0] | WGM1[1:0] | |||||
| 0x81 | TCCR1B | 7:0 | ICNC1 | ICES1 | WGM1[3] | WGM1[2] | CS1[2:0] | |||
| 0x82 | TCCR1C | 7:0 | FOC1A | FOC1B | ||||||
0x83 |
Reserved | |||||||||
| 0x84 | TCNT1L and TCNT1H | 7:0 | TCNT1[7:0] | |||||||
| 15:8 | TCNT1[15:8] | |||||||||
| 0x86 | ICR1L and ICR1H | 7:0 | ICR1[7:0] | |||||||
| 15:8 | ICR1[15:8] | |||||||||
| 0x88 | OCR1AL and OCR1AH | 7:0 | OCR1A[7:0] | |||||||
| 15:8 | OCR1A[15:8] | |||||||||
| 0x8A | OCR1BL and OCR1BH | 7:0 | OCR1B[7:0] | |||||||
| 15:8 | OCR1B[15:8] | |||||||||
0x8C ... 0x8F |
Reserved | |||||||||
| 0x90 | TCCR3A | 7:0 | COM3A[1:0] | COM3B[1:0] | WGM3[1:0] | |||||
| 0x91 | TCCR3B | 7:0 | ICNC3 | ICES3 | WGM3[3] | WGM3[2] | CS3[2:0] | |||
| 0x92 | TCCR3C | 7:0 | FOC3A | FOC3B | ||||||
0x93 |
Reserved | |||||||||
| 0x94 | TCNT3L and TCNT3H | 7:0 | TCNT3[7:0] | |||||||
| 15:8 | TCNT3[15:8] | |||||||||
| 0x96 | ICR3L and ICR3H | 7:0 | ICR3[7:0] | |||||||
| 15:8 | ICR3[15:8] | |||||||||
| 0x98 | OCR3AL and OCR3AH | 7:0 | OCR3A[7:0] | |||||||
| 15:8 | OCR3A[15:8] | |||||||||
| 0x9A | OCR3BL and OCR3BH | 7:0 | OCR3B[7:0] | |||||||
| 15:8 | OCR3B[15:8] | |||||||||
0x9C ... 0x9F |
Reserved | |||||||||
| 0xA0 | TCCR4A | 7:0 | COM4A[1:0] | COM4B[1:0] | WGM4[1:0] | |||||
| 0xA1 | TCCR4B | 7:0 | ICNC4 | ICES4 | WGM4[3] | WGM4[2] | CS4[2:0] | |||
| 0xA2 | TCCR4C | 7:0 | FOC4A | FOC4B | ||||||
0xA3 |
Reserved | |||||||||
| 0xA4 | TCNT4L and TCNT4H | 7:0 | TCNT4[7:0] | |||||||
| 15:8 | TCNT4[15:8] | |||||||||
| 0xA6 | ICR4L and ICR4H | 7:0 | ICR4[7:0] | |||||||
| 15:8 | ICR4[15:8] | |||||||||
| 0xA8 | OCR4AL and OCR4AH | 7:0 | OCR4A[7:0] | |||||||
| 15:8 | OCR4A[15:8] | |||||||||
| 0xAA | OCR4BL and OCR4BH | 7:0 | OCR4B[7:0] | |||||||
| 15:8 | OCR4B[15:8] | |||||||||
| 0xAC | SPCR1 | 7:0 | SPIE1 | SPE1 | DORD1 | MSTR1 | CPOL1 | CPHA1 | SPR1 [1:0] | |
| 0xAD | SPSR1 | 7:0 | SPIF1 | WCOL1 | SPI2X1 | |||||
| 0xAE | SPDR1 | 7:0 | SPID1[7:0] | |||||||
0xAF |
Reserved | |||||||||
| 0xB0 | TCCR2A | 7:0 | COM2A[1:0] | COM2B[1:0] | WGM2[1:0] | |||||
| 0xB1 | TCCR2B | 7:0 | FOC2A | FOC2B | WGM2 [2] | CS2[2:0] | ||||
| 0xB2 | TCNT2 | 7:0 | TCNT2[7:0] | |||||||
| 0xB3 | OCR2A | 7:0 | OCR2A[7:0] | |||||||
| 0xB4 | OCR2B | 7:0 | OCR2B[7:0] | |||||||
0xB5 |
Reserved | |||||||||
| 0xB6 | ASSR | 7:0 | EXCLK | AS2 | TCN2UB | OCR2AUB | OCR2BUB | TCR2AUB | TCR2BUB | |
0xB7 |
Reserved | |||||||||
| 0xB8 | TWBR0 | 7:0 | TWBR [7:0] | |||||||
| 0xB9 | TWSR0 | 7:0 | TWS7 | TWS6 | TWS5 | TWS4 | TWS3 | TWPS[1:0] | ||
| 0xBA | TWAR0 | 7:0 | TWA[6:0] | TWGCE | ||||||
| 0xBB | TWDR0 | 7:0 | TWD[7:0] | |||||||
| 0xBC | TWCR0 | 7:0 | TWINT | TWEA | TWSTA | TWSTO | TWWC | TWEN | TWIE | |
| 0xBD | TWAMR0 | 7:0 | TWAM[6:0] | |||||||
0xBE ... 0xBF |
Reserved | |||||||||
| 0xC0 | UCSR0A | 7:0 | RXCn | TXCn | UDREn | FEn | DORn | UPEn | U2Xn | MPCMn |
| 0xC1 | UCSR0B | 7:0 | RXCIEn | TXCIEn | UDRIEn | RXENn | TXENn | UCSZn2 | RXB8n | TXB8n |
| 0xC2 | UCSR0C | 7:0 | UMSELn[1:0] | UPMn[1:0] | USBSn | UCSZn1 / UDORDn | UCSZn0 / UCPHAn | UCPOLn | ||
0xC3 |
Reserved | |||||||||
| 0xC4 | UBRR0L and UBRR0H | 7:0 | UBRRn[7:0] | |||||||
| 15:8 | UBRRn[11:8] | |||||||||
| 0xC6 | UDR0 | 7:0 | TXB / RXB[7:0] | |||||||
| 0xC7 | UDR1 | 7:0 | TXB / RXB[7:0] | |||||||
| 0xC8 | UCSR1A | 7:0 | RXCn | TXCn | UDREn | FEn | DORn | UPEn | U2Xn | MPCMn |
| 0xC9 | UCSR1B | 7:0 | RXCIEn | TXCIEn | UDRIEn | RXENn | TXENn | UCSZn2 | RXB8n | TXB8n |
| 0xCA | UCSR1C | 7:0 | UMSELn[1:0] | UPMn[1:0] | USBSn | UCSZn1 / UDORDn | UCSZn0 / UCPHAn | UCPOLn | ||
0xCB |
Reserved | |||||||||
| 0xCC | UBRR1L and UBRR1H | 7:0 | UBRRn[7:0] | |||||||
| 15:8 | UBRRn[11:8] | |||||||||
0xCE ... 0xD7 |
Reserved | |||||||||
| 0xD8 | TWBR1 | 7:0 | TWBR [7:0] | |||||||
| 0xD9 | TWSR1 | 7:0 | TWS7 | TWS6 | TWS5 | TWS4 | TWS3 | TWPS[1:0] | ||
| 0xDA | TWAR1 | 7:0 | TWA[6:0] | TWGCE | ||||||
| 0xDB | TWDR1 | 7:0 | TWD[7:0] | |||||||
| 0xDC | TWCR1 | 7:0 | TWINT | TWEA | TWSTA | TWSTO | TWWC | TWEN | TWIE | |
| 0xDD | TWAMR1 | 7:0 | TWAM[6:0] | |||||||