| (PCINT8/XCK0/T0) PB0 | 1 • | 40 | PA0 (ADC0/PCINT0) |
| (PCINT9/CLKO/T1) PB1 | 2 | 39 | PA1 (ADC1/PCINT1) |
| (PCINT10/INT2/AIN0) PB2 | 3 | 38 | PA2 (ADC2/PCINT2) |
| (PCINT11/OC0A/AIN1) PB3 | 4 | 37 | PA3 (ADC3/PCINT3) |
| (PCINT12/OC0B/SS) PB4 | 5 | 36 | PA4 (ADC4/PCINT4) |
| (PCINT13/ICP3*/MOSI) PB5 | 6 | 35 | PA5 (ADC5/PCINT5) |
| (PCINT14/OC3A*/MISO) PB6 | 7 | 34 | PA6 (ADC6/PCINT6) |
| (PCINT15/OC3B*/SCK) PB7 | 8 | 33 | PA7 (ADC7/PCINT7) |
| RESET | 9 | 32 | AREF |
| Vcc | 10 | 31 | GND |
| GND | 11 | 30 | AVcc |
| XTAL2 | 12 | 29 | PC7 (TOSC2/PCINT23) |
| XTAL1 | 13 | 28 | PC6 (TOSC1/PCINT22) |
| (PCINT24/RXD0) PD0 | 14 | 27 | PC5 (TDI/PCINT21) |
| (PCINT25/TXD0) PD1 | 15 | 26 | PC4 (TDO/PCINT20) |
| (PCINT26/RXD1/INT0) PD2 | 16 | 25 | PC3 (TMS/PCINT19) |
| (PCINT27/TXD1/INT1) PD3 | 17 | 24 | PC2 (TCK/PCINT18) |
| (PCINT28/XCK1/OC1B) PD4 | 18 | 23 | PC1 (SDA/PCINT17) |
| (PCINT29/OC1A) PD5 | 19 | 22 | PC0 (SCL/PCINT16) |
| (PCINT30/OC2B/ICP) PD6 | 20 | 21 | PD7 (OC2A/PCINT31) |
| Pin | Symbol | Description |
|---|---|---|
| 1 | (PCINT8/XCK0/T0) PB0 | port B |
| 2 | (PCINT9/CLKO/T1) PB1 | clock output; port B |
| 3 | (PCINT10/INT2/AIN0) PB2 | external interrupt 2; port B |
| 4 | (PCINT11/OC0A/AIN1) PB3 | port B |
| 5 | (PCINT12/OC0B/SS) PB4 | SPI slave select; port B |
| 6 | (PCINT13/ICP3*/MOSI) PB5 | SPI master output/slave input; port B |
| 7 | (PCINT14/OC3A*/MISO) PB6 | SPI master input/slave output; port B |
| 8 | (PCINT15/OC3B*/SCK) PB7 | SPI master clock; port B |
| 9 | RESET | reset (active low) |
| 10 | Vcc | supply voltage |
| 11 | GND | ground |
| 12 | XTAL2 | clock oscillator pin 2 |
| 13 | XTAL1 | clock oscillator pin 1 |
| 14 | (PCINT24/RXD0) PD0 | port D |
| 15 | (PCINT25/TXD0) PD1 | port D |
| 16 | (PCINT26/RXD1/INT0) PD2 | external interrupt 0; port D |
| 17 | (PCINT27/TXD1/INT1) PD3 | external interrupt 1; port D |
| 18 | (PCINT28/XCK1/OC1B) PD4 | port D |
| 19 | (PCINT29/OC1A) PD5 | port D |
| 20 | (PCINT30/OC2B/ICP) PD6 | port D |
| 21 | PD7 (OC2A/PCINT31) | port D |
| 22 | PC0 (SCL/PCINT16) | 2-wire clock line; port C |
| 23 | PC1 (SDA/PCINT17) | 2-wire data line; port C |
| 24 | PC2 (TCK/PCINT18) | JTAG test clock; port C |
| 25 | PC3 (TMS/PCINT19) | JTAG test mode select; port C |
| 26 | PC4 (TDO/PCINT20) | JTAG test data output; port C |
| 27 | PC5 (TDI/PCINT21) | JTAG test data input; port C |
| 28 | PC6 (TOSC1/PCINT22) | timer oscillator pin 1; port C |
| 29 | PC7 (TOSC2/PCINT23) | timer oscillator pin 2; port C |
| 30 | AVcc | A/D converter supply voltage |
| 31 | GND | ground |
| 32 | AREF | analog reference for A/D converter |
| 33 | PA7 (ADC7/PCINT7) | port A |
| 34 | PA6 (ADC6/PCINT6) | port A |
| 35 | PA5 (ADC5/PCINT5) | port A |
| 36 | PA4 (ADC4/PCINT4) | port A |
| 37 | PA3 (ADC3/PCINT3) | port A |
| 38 | PA2 (ADC2/PCINT2) | port A |
| 39 | PA1 (ADC1/PCINT1) | port A |
| 40 | PA0 (ADC0/PCINT0) | port A |
| Parameter | Value | Unit |
|---|---|---|
| Flash memory | 16K (ATmega164P) 32K (ATmega324P) 64K (ATmega644P) 128K (ATmega1284P) | bytes |
| Internal SRAM | 1K (ATmega164P) 2K (ATmega324P) 4K (ATmega644P) 16K (ATmega1284P) | bytes |
| EEPROM | 512 (ATmega164P) 1K (ATmega324P) 2K (ATmega644P) 4K (ATmega1284P) | bytes |
| Programmable I/O lines | 32 |
Note: Data is maintained by an independent source and accuracy is not guaranteed. Check with the manufacturer's datasheet for up-to-date information.