USB drivers working previously with K50 family stop working on MK20DX128VLF5

[maximosipov]

After USB reset and first descriptor exchange DFN8 error is generated by the USB controller (device mode).

Error is observed on both USB Stack http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MEDICALUSB&fpsp=1&tab=Design_Tools_Tab and K20 Freedom board USB CDC code.

Any hint on this issue? Working CDC code or recommendations on workarounds are highly appreciated.

[maximosipov]

Hi,

First of all, mcuoneclipse is amazing and CDC driver is very cool. Unfortunately didn't help in my case, so I suspect a hardware problem - either in chip or layout (however layout is trivial)...:smileysad:

Regards,

Max

[CarlosCasillas]

Hi Maxim,

Have you tested the CDC example that Erich Styger sent you, but using a FRDM-K20D50M board?

I just tested it and it worked properly. If you are getting troubles with your custom hardware, have you ensured if you are using the same crystal value than FRDM-K20D50M board (8 MHz), in order to have a valid clock initialization?

Hope this will be useful for you.

Best regards!

/Carlos

[maximosipov]

Thank you - I checked USB clock as a very first step, on USB data lines - it all correct. So only HW options left.

[Monica]

Hello Maxim,

was this example useful? Please keep us posted, we'd like to know :smileywink:

Best,

Monica.

[BlackNight]

Hi Maxim,

attached is an example I'm using.

See USB CDC with the FRDM-K20D50M | MCU on Eclipse

Erich