2025-02-10 02:24 PM
Hi All, sanity check sought:
I'm using the blue pill (STM32F103C8T6) for a audio project powered & controlled through the serial/USB.
I'm using the STM32 cube and a dev board for the s/w which looks ok; in terms of software I've followed https://controllerstech.com/send-and-receive-data-to-pc-without-uart-stm32-usb-com/ and that works ok.
My concern is with the serial - assuming the above s/w process outlined in the link, is this everything I need for USB communications hardware wise? Or in general anything I'm missing? For instance:
*I've seen resistors on the D+ and D- lines in previous designs, though I'm not sure is these are needed
*I'm using the MIC29302WU as I've quite high current demands from the USB (<500mA) to drive a speaker (this explains the LDO's presence / the requirements)
*Can the VBAT pin be left unconnected or does it need a pullup/down? even if not used
*Boot0 and 1 tied low ok? I'll be using the SWD to flash and won't need to debug/program through the USB
*20pF ok?
Solved! Go to Solution.
2025-02-10 07:08 PM
A pullup on DP is required on the STM32F103.
*Introduction to USB hardware and PCB guidelines using STM32 MCUs - Application note
> Can the VBAT pin be left unconnected or does it need a pullup/down? even if not used
If no external battery is used in the application, it is highly recommended to connect VBAT
externally to VDD.
Getting started with STM32F10xxx hardware development - undefined
> Boot0 and 1 tied low ok? I'll be using the SWD to flash and won't need to debug/program through the USB
Yes.
2025-02-10 07:08 PM
A pullup on DP is required on the STM32F103.
*Introduction to USB hardware and PCB guidelines using STM32 MCUs - Application note
> Can the VBAT pin be left unconnected or does it need a pullup/down? even if not used
If no external battery is used in the application, it is highly recommended to connect VBAT
externally to VDD.
Getting started with STM32F10xxx hardware development - undefined
> Boot0 and 1 tied low ok? I'll be using the SWD to flash and won't need to debug/program through the USB
Yes.