ATtiny85 Mini Arduino Compatible Microcontroller

The ATtiny85 is a great little microcontroller you program with the Arduino IDE just like the Arduino UNO and Mega. It is a very low cost solution and space saving option for Arduino-based designs that don't need the full power of an Arduino UNO or Mega board. Supports both I2C and SPI via its Universal Serial Interface for optimal use of it's 5 I/O Pins.

The differences between the ATtiny85 and Arduino UNO:

• Lower Price
• Smaller size (8 pin chip vs 16 pin chip on a breakout board)
• 6 I/O Pins(3 Analog + 2 Digital + 1 Reset) vs 20 I/O Pins (6 Analog + 14 Digital)
• 8KB flash memory vs 32KB flash memory (ATtiny can hold smaller programs)
• 512 bytes of RAM vs 2KB of RAM (ATtiny can store less data)
• The ATtiny has no hardware serial port or I2C port (Wire library), making communication trickier. (There are workarounds, like the SoftwareSerial library or the TinyWire library which are less robust and flexible.)
• External Crystal vs Crystal on Arduino UNO board

In short, if your project requires only a few simple inputs and/or outputs and you are familiar with the Arduino UNO, you’re probably going to do well using an ATtiny. If you’re trying to hook up more components or do complex communication and/or data processing, you’re probably better off with the Arduino Uno or Arduino Mega for even more ports. We recommend this for tinkerers who have already had experience with an Arduino Board before; if you're a complete beginner, you should buy the Arduino UNO which is simpler to work with.

Specifications

• Core Processor: AVR
• Core Size: 8-Bit
• Max Clock Frequency: 20MHz
• Connectivity: Universal Serial Interface
• Extra Features: Brown-out Detect/Reset, POR, PWM, WDT
• Number of I /O: 6
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• EEPROM Size: 512 x 8
• RAM Size: 512 x 8
• Operating Supply Voltage: 2.7 V - 5.5 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• IC Package: 8-DIP
  

For for information about using I2C and SPI (the communication protocols for the ATtiny) visit: I2C library and example of using SPI.