AnsweredAssumed Answered

USB will not enumerate

Question asked by Ove-Anders Gaarder Aune on Dec 9, 2015
Latest reply on Dec 14, 2015 by Ove-Anders Gaarder Aune

I managed to get the PLL up and running with external crystal, generating PLLclk = 48Mhz, which is feed to USB through MCGPLLCLK ( PLLFLLSEL = 1).


Core runs at 48Mhz, bus, flash and flexbus runs at 24Mhz.


I have verified the frequencies on PTC3.


When I connect the USB cable the software makes transition som BLPE/VLPR -> RUN/PEE, after this is verified and done the USB starts up. But for some reason the computer will not recognize the device. If I plug into a win7 computer it said that it "failed to get device description".


But if I break the software I can see that I do get a token from the computer with device descriptor request and it the protocol stack ( Freescale 4.1.1 ) breaks at the usb_descriptor.c file where it does get the descriptor, the protocol stack flags no errors.


Btw, I also tried running of IRC48, with same result.


Any idea why the computer won't recognize it ?