Program ATtiny85 with Arduino UNO

Step 1: Parts List

• Arduino UNO
• Arduino Attiny85
• 10 uF capacitor
• breadboard

Step 2: Wiring

• ATtiny Reset <–> Arduino Pin 10
• ATtiny Pin 0 <–> Arduino Pin 11
• ATtiny Pin 1 <–> Arduino Pin 12
• ATtiny Pin 2 <–> Arduino Pin 13
• VCC <–> 5v
• GND <–> GND
• ** 10 uF capacitor (+) <–> Arduino Pin Reset
• ** 10 uF capacitor (-) <–> Arduino Pin GND

Step 3: Step by step

• Upload ArduinoISP sketch into Arduino
• Power down
• Make connections to ATtiny chip
• Power up (ATtiny will start running)
• Select proper board via Tools/Board (ATtiny85 internal 1MHz clock)
• Select proper programmer via Tools/Programmer/Arduino as ISP
• Upload sketch

Note: Clock frequencies

• From the factory, ATtiny85 is fused for 1 MHz internal clock.
• You can change the fusing to use 8 MHz internal clock by running “Burn Bootloader”. You only need to do this once (per chip)
• You can attach an external crystal to run at up to 20 MHz. Select 20 MHz board and run “Burn Bootloader”. I think you need to hook up the crystal before programming.