I am developing a board that shall work with a Computer. The last project I developed I was suggested to ask to online support to give a review about my design to optimize it (I have not a very deep knowledge of electronics, after all). Does anyone know h

[AKuma.54]

I can help you. You can explain your design and requirements. And ask your question.

[MMast.11]

Thank you! The idea is to use a STM32F103C (it would be the core of a BluePill) to build a simple keyboard/joystick that communicate as an USB HID. The difficult part of this is that the project is price oriented, and so the final goal is to produce a pcb that it is cheap as possible. Can I upload here the schematics so you can tell me if it would work?

[MMast.11]

I think it's better if I upload the file directly.

I was thinking on mounting a 6-pole jumper to use just one USB port and commute the pins between the programming and the USB host if this could work

[MMast.11]

Mr AKuma, I have uploaded the pdf. Would you rather have uploaded a picture of the scheme?

I really would like to have your opinion.

Marco

[Tesla DeLorean]

Pull BOOT0 LOW normally, provide means to change for programming via System Loader, add some decoupling capacitors.

Provide some methods for debugging programming.

Avoid use of PA13/PA14 so the debugger can use.

Consider USART1 PA9/PA10 programming, or debug output, see AN2606

[MMast.11]

Thank you. I am not sure I understood everything correctly, but this should be better

Marco

[MMast.11]

Please bear with my ignorance in this sector. I really would like to have an opinion on this circuit and I am doing my best.

[MMast.11]

I am sorry, I need more information.

In the schematics decoupling has been provided with capacitor C3. The Pin PA13/14 have been freed (Previously it was used according to an example i found with a Bluepill on youtube). I am not really sure if I need to add a transistor on DP line of STM32 as pictured on AN2606.

Please give me more suggestions.

Marco