I would like to have some clarification about the USB circuit needed for the stm32f103 (and similar), I am making a simple development board just to start learning this MCU
This is taked from the maple mini schematics also the rev5/6 and other boards present a similar circuit. DISC cames from PB9
my guess is that the 2 transistors stay there to power the R10 to pull up DP when the board is connected to USB otherwise, when powered from other sources, DP and DM could be used as normal GPIO (PA12 and 11). Am i wrong?
about the two cap for the usb line (c10 and 11) and the pull up for DP (R10) i saw them only in a few boards, could i live without them or is it suggested to add all?
In other schematics (example: http://eleccelerator.com/stm32f4stamp-breakout-board/) i found that sometimes the USB ID is wired to PA10, what does it mean?
Thanks for reading