Assembly, parts, usage, user programming, and other information:
- https://opensauce.com/badge-25/
- https://www.digikey.com/en/maker/tutorials/2025/assembling-your-2025-open-sauce-badge
After flashing os_2025.hex to your ATtiny85, the chip's fuses need to be configured for correct operation. Warning:
after setting fuses as described below, you will be unable to re-program your ATtiny or change additional fuses without
the use of high voltage programming!
Programming with AVRDUDE
This is assuming you are using a USBASP programmer - unofficial, cheap, but not an Atmel product.
avrdude -c usbasp -p t85 -U flash:w:os_2025.hex:i
Fuse setting with AVRDUDE
The following command sets appropriate fuses:
avrdude -c usbasp -p t85 \
-U lfuse:w:0xE2:m \
-U hfuse:w:0x5F:m \
-U efuse:w:0xFF:m \
-U lock:w:0xFF:m
The fuses required are - described as what changes from the defaults:
| Fuse | Setting | Comment |
|---|---|---|
| Low | 0xE2 | Clear CKDIV8 - run cpu at full 8MHz |
| High | 0x5F | Set RSTDISBL - reconfigure reset pin as GPIO* |
| Extended | 0xFF | default |
| Lock | 0xFF | default |
* Warning, after setting fuses as described above, you will be unable to re-program your ATtiny or change additional fuses without the use of high voltage programming!