2018-09-01 10:03 AM
When I put 3.3V to boot0 and 0V to boot1 and then 0V to NRST,
I don't get DFU mode. I have to cycle power withboot0 HI to the MCU to get DFU mode.
The docs suggest different. have I misinterpreted the docs?
Thanks, John
2018-09-01 11:17 AM
The System Loader is entered when BOOT0=High
USB connectivity might be an issue if your external oscillator/clock source is slow to start properly.
The PC would also need to sense a change in state on the USB connection. VBUS would need to be able to pulse DP
AN2606 and AN3156 cover some of the details
https://www.st.com/content/ccc/resource/technical/document/application_note/b9/9b/16/3a/12/1e/40/0c/CD00167594.pdf/files/CD00167594.pdf/jcr:content/translations/en.CD00167594.pdf
https://www.st.com/content/ccc/resource/technical/document/application_note/6a/17/92/02/58/98/45/0c/CD00264379.pdf/files/CD00264379.pdf/jcr:content/translations/en.CD00264379.pdf
On my F2/F4 boards a can jump into the ROM from a terminal console, and it connects via USB/DFU, so power cycling definitely isn't a requirement.
Other boards (Flight Controllers) I've had to press a BOOT button and plug in USB while holding it.
