I recently got one of those cheap chinese attiny USB socket boards and discovered that in order to use the arduino IDE, you need to burn a bootloader onto it. I found a few tutorials online, but a lot of them felt incomplete or included redundant steps.
Video:
Here's how to burn a bootloader to an Attiny85 using an Arduino UNO:
- Install the Arduino IDE https://www.arduino.cc/en/Main/Software
- Install the digistump drivers https://github.com/digistump/DigistumpArduino/releases
- Open the arduino IDE and go to file > preferences.
- Add http://digistump.com/package_digistump_index.json to the additional boards manager URLs.
- Go to tools > board > boards manager.
- Search for digistump, and install Digistump AVR boards.
- Connect your arduino uno via USB.
- Go to file > examples > 11. ArduinoISP > ArduinoISP to open the ArduinoISP sketch.
- Hit the arrow button to upload it to your arduino.
- Unplug your arduino and get your Attiny85, breadboard, some wires, and a 10uF capacitor.
- Wire the following:
| Attiny physical pin | Arduino GPIO/Pin |
|---|---|
| 1 | 10 |
| 4 | GND |
| 5 | 11 |
| 6 | 12 |
| 7 | 13 |
| 8 | 5V |
Also connect a 10uF capacitor between arduino RST and arduino GND. If using an electrolytic capacitor, put anode on RST and cathode on GND.
- Connect your arduino again via USB and go into the Arduino IDE. Check what port it's connected to. In my case it's COM3.
- Edit the burn_attiny85_bootloader.bat file from this repository (right click and edit). Edit the part that says -PCOM22 to match your port. In my case since I use COM3, I'll edit it to -PCOM3
- Save and copy both the bat file and t85_default.hex to your arduino install directory.
- Run the bat file, and it should now burn the bootloader to your attiny85.
After adding the bootloader, you can now upload via arduino. There's a testsketch in this repo if you just want to blink the debug LED.
- Write your sketch as usual.
- Connect your attiny to your USB socket board. But don't plug it to the computer yet.
- In the arduino IDE, pick Digispark (Default - 16.5mhz). Port doesn't matter.
- Hit upload sketch.
- After compiling, the IDE will ask you to plug your attiny in. Do that, and the sketch will upload.
Credits & sources: https://www.youtube.com/watch?v=FI3s4d2I1eQ https://create.arduino.cc/projecthub/arjun/programming-attiny85-with-arduino-uno-afb829 https://digistump.com/board/index.php?topic=1841.0