Can't get stm32 to detect my keyboard, what am I doing wrong?

[StephanMair]

Posted on May 27, 2014 at 07:03

After I plugged in the keyboard, the ConnSts always return a value that tells the MCU nothing is connected. All my keyboards (3 of them) are fine.

I've properly connected DM & DP (PA11&12).

I've connected PA9 to Vbus line.

I'm using STMP214 to provide VBUS current.

All those connections and configurations are done by the book, yet nothing's working out.

One last thing, for reason still unknown my VBUS is 4.65±0.05V instead of 4.99 ~ 5.01 V, is this a problem?  I know the USB specs can be quite draconian but 0.5 V difference shouldn't matter, right?

Please help, thanks.