Firmware found here: https://github.com/tetrabiodistributed/papra-pcb-firmware/tree/main/papracode
Notes for programming:
- Make a UPDI Programmer: https://create.arduino.cc/projecthub/john-bradnam/create-your-own-updi-programmer-1e55f1?ref=user&ref_id=466812&offset=6
- The board features a UPDI header on the top left of the PCB (top being the side with the battery connectors) the pins are top to bottom 5V, GND and data.
- Setup Arduino: https://www.hackster.io/john-bradnam/using-the-new-attiny-processors-with-arduino-ide-612185
- You will need to use the megaTinyCore library by SpenceKonde: https://github.com/SpenceKonde/megaTinyCore
Upload settings can be found in the arduino program.
Please note that there are a number of ATTiny SKUs that are compatible with this PCB and code, please refer to the below table when choosing an appropriate IC.
| Model number | Confirmed | Notes |
|---|---|---|
| ATtiny204SSN_, | Yes | See Below(1) |
| ATtiny404SSN_, | Yes | |
| ATtiny804SSN_, | Yes | |
| ATtiny1604SSN_, | Yes | |
| ATtiny214SSN_, | Yes | See Below(1) |
| ATtiny414SSN_, | Yes | |
| ATtiny814SSN_, | Yes | |
| ATtiny1614SSN_, | Yes | |
| ATtiny1624SSU, | Yes |
(1)ATtiny 204 and 214 have limited (2K) flash memory for program space, but the firmware can be made to fit by sacraficing the bootup LED sequence.