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USB clock frequency

Pradeep Kumar M
Prodigy 220 points
Other Parts Discussed in Thread: TMS320VC5506

Hi,

     I am using 5509A chip...  I want to make USB as boot loader.... I have created boot table for USB and configured the hardware[BootM[3:0]=001b] as per the data sheet..  When i use thesycon USBIO driver to download the boot table, pc fails to detect the device.... I've used 20MHZ as clock input, but the USB requires 48MHZ for its operation...  Since i am not using 5509A Dsk(created kit by own with reference to circuit manual), how can i alter the clock register...  Can i use 48 MHZ as input clock? or any other method to alter the USB clock....

 

Regards

Pradeep

  • 0
    TI__Genius 14965 points

    Hi,

     

    I understand your issue and I'll follow up.

    Regards,

    Hyun

  • 0 in reply to Hyun Kim
    TI__Genius 14965 points

    Hi,

     

    USB boot ROM code is expecting 12MHz clock in and set to CPU and USB to 48MHz. So if you supply 20MHz clock in, you internal clock will be set to higher than 48MHz.

    Also USB boot selection is  BOOTM[3:0]= 0010b (2).

    Regards,

    Hyun

  • 0
    TI__Expert 6995 points

    Pradeep,

     

    To expand on Hyun's answer. C5509 has two PLLs: One system PLL and one USB PLL. To support 12Mbps USB throughput, the USB section most run at exactly 48MHz. The bootloader assumes a 12.0MHz clock and configures the USB PLL to 4X the input clock. Thus, if you supply a 20MHz clock input to C5509, the bootloader will set the USB PLL to 4X, providing a 80MHz clock to the USB module. This would not allow USB to operate with 12Mbps data transfers.

    For USB boot, GPIO[3:0] need to be set to 0010b.

     

    See http://focus.ti.com/lit/an/spra840c/spra840c.pdf for more details.

  • 0 in reply to PedroGelabert
    Prodigy 220 points

     

    Thank for reply... Now i connected 12MHZ crystal accross X1 and X2, but still it is not recognised....  I configured GPIO[3:0] =0010b (typed wrongly in last post).... What are area should i troubleshoot?....

     

    Circuit diagram:

    Thesycon Output:

    Scanning for attached USB devices:

    There are no USB devices attached to the USBIO driver.
    OnDeviceChange message: 00000007 (DBT_DEVNODES_CHANGED)
    OnDeviceChange message: 00000007 (DBT_DEVNODES_CHANGED)
    OnDeviceChange message: 00000007 (DBT_DEVNODES_CHANGED)
    OnDeviceChange message: 00000007 (DBT_DEVNODES_CHANGED)
    OnDeviceChange message: 00000007 (DBT_DEVNODES_CHANGED)
    OnDeviceChange message: 00000007 (DBT_DEVNODES_CHANGED)

    Regards

    Pradeep

     

     

  • 0 in reply to Pradeep Kumar M
    Prodigy 220 points

     

    Following were the supply details...

                                              USBPLLVDD=1.6V
                                              USBPLLVSS=0V
                                               USBVDD=3.3V

     

    I have connected only D+ and D- to the USB pin.... PC does not recognise the chip....

     

    Regards

    Pradeep

  • 0 in reply to Pradeep Kumar M
    TI__Expert 6995 points

    Pradeep,

     

    The connections, clock speed, and BOOTMOD are correct. There is an application note that might help you. Please look over:

     

    Using the TMS320VC5506/C5507/C5509/C5509A USB Bootloader

     

    http://focus.ti.com/lit/an/spra840c/spra840c.pdf

     

    bst regards,

      Pedro