What could cause Usb Bad Descriptor and how to debug

[FGERA.1]

Hello,

It's my first try with Usb directly on an MCU, i used stm32cube mx and code generator to make a first test but when i'm running a simple cdc code i get windows throwing me an error about usb bad descriptor.

I linked my ioc and my usb schematic, i tried with and without the filter inductance(usb connected is just wired to an exti)

[Uwe Bonnes]

First test with system bootloader if your board enumerates. If yes, the problem is in your code. It not carefully check for hardware errors, bridges, opens, wrong parts etc.

[Piranha · Accepted solution]

The D+/D- lines are reversed around TVS1. Also for TVS1 you should use 82400102 from WE or USBLC6-2SC6 from ST.

[Uwe Bonnes]

And they should be directly connected!

[FGERA.1]

the lines was reversed, very dumb mistake, i'm able to use bootloader and cube mx example, thanks.

thanks for the tip for tvs @Piranha​ , this device will be in an industrial environement direct connection seems little dangerous isn't it ?

I'm not a huge fan of ST's Hal, what do you guy's use for interact with usb ?

[Piranha]

I've not used USB stacks till now, but it looks like TinyUSB is getting traction.