keep the little piece of card, you need it! it has the pin-out assignments. so forget powering by the micro-usb, do this:
- flip the jumper from E5V to U5V
- cut off a random USB cable and strip down the black, red, white and green
- solder 5V (Red) to pin 6 of CN7
- solder GND (black) to pin 8 of CN7
- solder USB+ (green) to pin 12 (PA12) of CN10
- solder USB- (white) to pin 14 (PA11) of CN10
then, plug it into a USB port of the development machine. then, use a screwdriver to short BOOT0 (pin 7 of CN7) to E5V (pin 6 of CN7), and at the same time press and then release the reset button (B2).
if you then do "lsusb" you should see a device come up "DFU mode" in the description. ta-daa, you can now upload a .bin file to it. you do that with any of the libopencm3-examples, you must do "make bin".
hm, that did not work, unfortunately, I cannot get into the DFU mode somehow. It will just start into the mode that is described in the Quick start section of the manual. I found some forum posts where people suggest to solder resistors to PA11 and PA12... but that should not alter the start mode, right? Any ideas what I could have done wrong?
Best, Peter