STM32F411CE USB CDC BlackPill

[LPrat.3]

I have a blackpill board with STM32F411 48 pins IC and CubeMX/CubeIDE at lastest versions. The USB is configured as device CDC, no Vbus.

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When I flash the board with generated code ​and plug USB in Windows 10 I get an error "invalid device descriptor". I have increased heap to 0x1000 without success.

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It not seems a hardware issue because I can enter the board in DFU and flash or erase device using CubeProgrammer.

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Any help will be apreciated.

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Leonardo​

[Pavel A.]

> It not seems a hardware issue 

Then there's an invalid device descriptor. Check with a bus analyzer.

[LPrat.3]

But the automatic code generated by CubeMX isn't reliable?

[LPrat.3]

I found the solution, I have to increase the heap (0x1000), but this isn't enough to solve. I need to change the automatic clock configs of CubeMX that use internal 16MHz clock as source to core.

The image bellow show the way that works.