usb virtual com STM32F103ZE, PC detected as ''Unknown Device'' - SOLVED

vbruno1 · ‎2016-04-12

Posted on April 12, 2016 at 11:58

On my board, I want to activate the virtual com usb, but not function.

I generated of the

https://www.dropbox.com/s/addgrf6w4k45cif/usb_usart1.zip?dl=0

with STM32CubeMx, enabling only USB and UART1 pins of the STM32F103ZE. The project make with Cubemx is attached.

The same code on demoboard STM3210E-EVAL working properly, in fact the PC sees the virtual com. I change only a parameter, the HSE Prediv Value, 1 for eval board, 2 for my board, because the crystal is different, 8MHz vs 16MHz respectively.

While my board does not work.

I attach scheme of my board.

Some advice? You have no idea what it is?

Thanks so much.

mark239955_stm1 · ‎2016-04-15

Posted on April 16, 2016 at 04:50

Have you checked that your crystal is running? You have a 10K resistor (R6) across it, which might be small enough to stop the oscillator.

vbruno1 · ‎2016-04-19

Posted on April 19, 2016 at 15:21

oh, those resistor isn't mounted.

I tested the micro with the program that use the usart port with my pc. Work nice. I think the clock work good.

You advice other tests?

you

advice

other tests

vbruno1 · ‎2016-04-21

Posted on April 21, 2016 at 12:12

I've solved. The quartz wasn't working. The system have the protection in this case, failure the external clock. The system works with internal clock.

''An external 4-16 MHz clock can be selected, in

which case it is monitored for failure. If failure is detected, the system automatically switches

back to the internal RC oscillator. A software interrupt is generated if enabled.'' pagg.16 datasheets STM32f103

you

advice

other tests