| (PCINT14/RESET) PC6 | 1 • | 28 | PC5 (ADC5/SCL/PCINT13) |
| (PCINT16/RXD) PD0 | 2 | 27 | PC4 (ADC4/SDA/PCINT12) |
| (PCINT17/TXD) PD1 | 3 | 26 | PC3 (ADC3/PCINT11) |
| (PCINT18/INT0) PD2 | 4 | 25 | PC2 (ADC2/PCINT10) |
| (PCINT19/OC2B/INT1) PD3 | 5 | 24 | PC1 (ADC1/PCINT9) |
| (PCINT20/XCK/T0) PD4 | 6 | 23 | PC0 (ADC0/PCINT8) |
| Vcc | 7 | 22 | GND |
| GND | 8 | 21 | AREF |
| (PCINT6/XTAL1/TOSC1) PB6 | 9 | 20 | AVcc |
| (PCINT17/XTAL2/TOSC2) PB7 | 10 | 19 | PB5 (SCK/PCINT5) |
| (PCINT21/OC0B/T1) PD5 | 11 | 18 | PB4 (MISO/PCINT4) |
| (PCINT22/OC0A/AIN0) PD6 | 12 | 17 | PB3 (MOSI/OC2A/PCINT3) |
| (PCINT23/AIN1) PD7 | 13 | 16 | PB2 (SS/OC1B/PCINT2) |
| (PCINT0/CLKO/ICP1) PB0 | 14 | 15 | PB1 (OC1A/PCINT1) |
| Pin | Symbol | Description |
|---|---|---|
| 1 | (PCINT14/RESET) PC6 | reset (active low); port C |
| 2 | (PCINT16/RXD) PD0 | port D |
| 3 | (PCINT17/TXD) PD1 | port D |
| 4 | (PCINT18/INT0) PD2 | external interrupt 0; port D |
| 5 | (PCINT19/OC2B/INT1) PD3 | external interrupt 1; port D |
| 6 | (PCINT20/XCK/T0) PD4 | port D |
| 7 | Vcc | supply voltage |
| 8 | GND | ground |
| 9 | (PCINT6/XTAL1/TOSC1) PB6 | clock oscillator pin 1; port B |
| 10 | (PCINT17/XTAL2/TOSC2) PB7 | clock oscillator pin 2; port B |
| 11 | (PCINT21/OC0B/T1) PD5 | port D |
| 12 | (PCINT22/OC0A/AIN0) PD6 | port D |
| 13 | (PCINT23/AIN1) PD7 | port D |
| 14 | (PCINT0/CLKO/ICP1) PB0 | clock output; port B |
| 15 | PB1 (OC1A/PCINT1) | port B |
| 16 | PB2 (SS/OC1B/PCINT2) | SPI slave select; port B |
| 17 | PB3 (MOSI/OC2A/PCINT3) | SPI master output/slave input; port B |
| 18 | PB4 (MISO/PCINT4) | SPI master input/slave output; port B |
| 19 | PB5 (SCK/PCINT5) | SPI master clock; port B |
| 20 | AVcc | A/D converter supply voltage |
| 21 | AREF | analog reference for A/D converter |
| 22 | GND | ground |
| 23 | PC0 (ADC0/PCINT8) | port C |
| 24 | PC1 (ADC1/PCINT9) | port C |
| 25 | PC2 (ADC2/PCINT10) | port C |
| 26 | PC3 (ADC3/PCINT11) | port C |
| 27 | PC4 (ADC4/SDA/PCINT12) | I2C Data pin; port C |
| 28 | PC5 (ADC5/SCL/PCINT13) | I2C Clock pin; port C |
| Parameter | Value | Unit |
|---|---|---|
| Flash memory | 4K (ATmega48) 8K (ATmega88) 16K (ATmega168) 32K (ATmega328P) | bytes |
| Internal SRAM | 512 (ATmega48) 1K (ATmega88) 1K (ATmega168) 2K (ATmega328P) | bytes |
| EEPROM | 256 (ATmega48) 512 (ATmega88) 512 (ATmega168) 1K (ATmega328P) | bytes |
| Programmable I/O lines | 23 | |
| Maximum clock frequency | 20 | MHz |
Note: Data is maintained by an independent source and accuracy is not guaranteed. Check with the manufacturer's datasheet for up-to-date information.