For the last few months I've been working on a project that used an STM32F030 microcontroller. Due to a shortage of GPIO I've had to use the SW debug pins for other functions. Until recently this wasn't a problem, since I just made sure to hook up the reset line from the ST-linkV2 and set it up as 'connect under reset'.
In the last few days I've been unable to reprogram the board though, all of a sudden it just started saying 'no target detected' any time I try to program it from Keil uVision.
I thought at first it may just be the ST-link that was playing up, so I tried a couple of others with no avail. Similar situation with multiple other target boards. Then I thought maybe something I had done accidentally in software, but nothing should really stop it from resetting itself and being able to program..?
The only way I've found I can reprogram them is if I pull the Boot0 line high, then power the uC up, and proceed to program. This is a total pain though since it means retrofitting every board I have with a boot0-high jumper.
Does anyone know what's going on here that might be stopping my programming this system the way I always have in the past?