The ATtiny85 is a minimal 8-bit AVR microcontroller in an 8-pin DIP package. It has 8KB flash, 512B SRAM, 512B EEPROM, and 6 usable I/O pins. Programmable via Arduino IDE with a USBtinyISP or via another Arduino.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | PB5/RESET | Reset active low, or I/O | I/O |
| 2 | PB3/ADC3 | Digital I/O, ADC3 | ADC |
| 3 | PB4/ADC2 | Digital I/O, ADC2 | ADC |
| 4 | GND | Ground | GND |
| 5 | PB0/MOSI/SDA | SPI MOSI, I2C SDA | BUS |
| 6 | PB1/MISO/OC1A | SPI MISO, PWM | BUS |
| 7 | PB2/SCK/SCL | SPI clock, I2C SCL | BUS |
| 8 | VCC | Supply voltage 2.7–5.5V | PWR |