I'm an amateur with several digisparks and trinkets that I use for small projects.
After reprogramming one digispark, it's not being detected at all when I plug it in. No USB sound. Tried it in multiple computers. Other digisparks are detected fine. The light turns on when power is supplied, but the sketch is not running.
I noticed afterwards that I had the wrong programmer selected, but I had uploaded the sketch to two digisparks and only one is broken, so I'm not sure if that is the issue. The sketch upload completed successfully. (I'm not sure what should happen when the wrong programmer is selected.)
I don't have an ISP programmer or an Arduino Uno, just digisparks and trinkets.
I saw one comment mentioning piggybacking a bad digispark on a good digispark to fix it, but couldn't find any specific instructions.
As I said, I have several digisparks, so it's not terribly important that I get this one working, and I've probably already spent more time than it is worth googling for solutions, but if all I need to do to fix it is solder headers between two digisparks and press a button, then I can manage that.
Is there any chance of a simple recovery, or should I just toss it in the trash?
The DigiSpark does not have USB support in hardware like most Arduino boards. Rather it does USB port emulation in the bootloader firmware using GPIO pins. If the bootloader is corrupted the USB won't work.
The fact that I stated I uploaded the sketch to two digisparks tells you that I am aware of how to successfully upload sketches to digisparks.
I am not aware of any method of uploading sketches to digisparks OTHER than "hitting Upload and then as soon as you see "plug in device now" immediately plugging in the DigiSpark"
So I'm confused what you think I was doing OTHER than this.
The fact that I stated that I do not have an ISP programmer tells you that I do not have an AVR ISP programmer, and that I was already aware of this option.
Thank you for confirming my suspicion that it is probably a corrupt bootloader.
This bring us back to the second half of my post:
Does anyone know if it is possible to fix this by piggybacking a bad digispark on a good digispark, and do you know of specific instructions?
Does anyone know of any method of recovery with only the use of digisparks and trinkets?
Maybe I am the one who is confused! Perhaps you are correct and this is the only way and I am thinking of another similar Arduino model where there are two ways to trigger upload. With most Arduino models, upload can be triggered from the IDE without re-pluggung the board, as I expect you know.