How to Install an ATtiny Bootloader With Virtual USB

Contributors: Shawn Hymel

Load Arduino ISP

To get started, we'll need to use another Arduino as an In-System Programmer (ISP) to send firmware to the target device (our ATtiny84). We'll only need to do this once in order to upload the micronucleus bootloader.

Hardware Connections

To start, make the following connections:

Upload ArduinoISP Sketch

Download the latest Arduino IDE.

Connect an FTDI breakout to the Arduino Pro Mini. In Arduino, select File > Examples > ArduinoISP > ArduinoISP. Select your Arduino board in Tools:

• Board: Arduino Pro or Pro Mini
• Processor: ATmega328 (3.3V, 8MHz)
• Port: \

Click upload to burn the Arduino ISP firmware to the Arduino Pro Mini.