The ATtiny85 Breakout board is the smallest Arduino Compatible board! It measures less that 1 square inch and has an onboard microUSB port! With 6 I/O pins an onboard voltage regulator and 3 Power Pins, this is a super awesome way to get Arduino based projects into the tiniest of places! Just plug in a microUSB cable to your computer and program using the Arduino software.
Features:
The smallest Arduino Compatible breakout board measuring less than 1 square inch!
Support for the Arduino IDE 1.0+ (OSX/Win/Linux)
Power via USB or External Source: 7V - 35V DC (12v or less recommended)
Automatic selection between 5V USB and External Source for Power
On-board 500ma 5V Regulator
On-board microUSB port for easy programming & power
6 I/O Pins: 2 pins (P3 & P4) are tied to USB (This means if your program actively communicates over USB they will be in use. If your program does not actively communicate over USB you can use all 6 I/O pins after programming via USB)
8k Flash Memory (about 6k after bootloader)
Communication Protocols Supported: I2C and SPI T
PWM on 3 pins (more possible with Software PWM)
ADC on 4 pins
Power LED and Status LED on-board
Pinout:
I/O Pins:
PO: Pin 0, AREF, SDA
P1: Pin 1, PWM, DO
P2: Pin 2, D/A, SCK
P3: Pin 3, D/A, USB
P4: Pin 4, PWM, D/A, USB
P5: Pin 5, D/A
Power Pins:
VIN: External Power Supply: 7V - 35V DC (keeping this under 12V is recommended to avoid unnecessary heat)
GND: Ground 0V
5V: Regulated 5V (If you have a regulated 5V power supply use this pin, otherwise use the VIN external supply which goes through the voltage regulator on board and does not go directly to the chip)
