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RTOS/TM4C1294NCPDT: UCB device detection problem

Richard Robinson
Intellectual 730 points
Part Number: TM4C1294NCPDT

Tool/software: TI-RTOS

Hi,

I have a TM4C1294 setup in host mode. Using the HID driver. I have one keyboard the will connected and others that will not. The only difference that I can see is the keyboard that works has USBDM pulled up. The devices that are not detected have USBDP pulled up. So it seems for some reason that it is only detecting low speed devices. Any ideas as to the source of the problem would be appreciated.

Thank you.

  • 0
    Genius 4630 points
    I have not studied the HID Class specification, but is there any requirement that keyboards be Low Speed? I am familiar with other USB Class specifications where faster speeds are not supported everywhere.
    You might also compare the USB Descriptors for the working keyboard to those keyboards that are not working. Any differences in the Descriptors may be causing the USBHCD code to skip over the device. Pay attention to the array that you pass to USBHCDRegisterDrivers() and review the code in the function in the pfnOpen field. That Open() function can return NULL to reject a device, so trace through the code to see why.
    You could also register a separate driver that matches anything unique about the USB Descriptors for those non-supported keyboards, borrowing code from the existing HID driver as necessary.
  • 0 in reply to Brian Willoughby
    Intellectual 730 points

    HI,

    Well I worked out what the issue was. It was a hardware problem. Thanks for your help.