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Question asked by riechardt.joerg on Jun 22, 2014
NRST is pulled high (+3,3V) by a 1,5k resistor, and gets manually connected to ground by a latch, that I press by hand.
BOOT0 is pulled to ground by a 3,6k resistor, and there is also a 2k resistor connected to BOOT0, which gets manually connected to +5V by a latch, that is pressed by hand.
The F105 is powered by a 5V to 3,3V regulator, the +5V for the regulator and the 2k pullup are from USB.
I tried long and short reset pulse (pressing the latch down), but it does not help.
So when I replug the USB cable, the whole thing is powered up again, but when I press the BOOT0 latch plus the NRST latch and release the NRST latch again (and then release the BOOT0 latch) it stays powered up. But that should make no difference, right?
The other difference is that Windows speaks to the „new“ USB device in case of replugging, while without replugging with only reset I don't know.
If I am in DFU mode and press reset latch, the F105 goes into my code, but Windows still shows „STM device in DFU mode“.
But even trying to communicate to the F105 over USB right after release of reset does not help to switch into DFU mode.

btw: How do I get the Forum Software to put my post under yours?
If I reply to yours, my post lands somewhere else.