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TMDSEVM6678L USB Functionality

Maurizio Donini
Prodigy 60 points
Other Parts Discussed in Thread: TMS320C6678, CDCM9102, TUSB7320

Hello,

can anybody suggest me what is the easiest way to add high speed usb host functionality to the TMDSEVM6678L evaluation board for the tms320c6678 DSP?

PCIe with TUSB7320EVM seem to be tricky to interconnect.

Any ideas?

thank you

regards

Maurizio

  • 0
    TI__Mastermind 42545 points

    Hi Maurizio,

    I'm not aware of any solutions for adding USB to the C6678 evaluation board. PCIE would be the interconnect solution found on most USB evaluation cards but there is a problem based on the C6678 evaluation card design. Most USB evaluation cards, including the TUSB7320EVM, would be in a PCIE peripheral board format. That board would expect to receive the 100MHz PCIE reference clock from the backplane. The C6678 evaluation card can be plugged into a PCE backplane using the PCIE adapter card but it is also designed to be act as a peripheral and doesn't drive the 100MHz reference clock. Without that clock, the PCIE interface will not operate between the two devices. 

    Regards, Bill

  • 0 in reply to Bill Taboada
    Prodigy 60 points

    Dear Bill,

    thank you for your useful answer. You confirmed some ideas I had. So please give me your opion about what I think to do:

    I plan to design a PCB that will have both AMC connector and PCIe connector to connect the C6678 evaluation board and the TUSB7320EVM board. I will also add the 100MHZ clock source, i.e. CDCM9102.

    Is it possible, according to you? should that reference clock controlled by the DSP or is it a free running clock?

    thank you

    regards,

    Maurizio

  • 0 in reply to Maurizio Donini
    TI__Mastermind 42545 points

    Hi Maurizio,

    The 100MHz reference clock can be free running as long as it is not driving the C6678 before voltage has been applied to the part, as specified in the power up sequencing section of the data  manual. With the external 100Mhz reference clock, the C6678 can act as a PCIE root complex while the TUSB7320EVM can act as an endpoint. Do you intend to combine these functions onto a signal board at some point in the future?

    Regards, Bill

  • 0 in reply to Bill Taboada
    Prodigy 60 points

    Hi Bill,

    thank you again for you support. Yes my goal is to integrate TUSB7320 and C6678 in a custom made board in the future but now I am searching a fast off the shelf solution to start development. So please be patient.. when you say that "the C6678 can act as a PCIE root complex while the TUSB7320EVM can act as an endpoint" do you mean that I can consider thet C6678 a USB host?

    Addictionally does the TUSB7320EVM have drivers for the embedded linux that runs on the C6678 development board?

    thank you very much

    kind regards,

    Maurizio

  • 0 in reply to Maurizio Donini
    TI__Mastermind 42545 points

    Hi Maurizio,

    Root complex and endpoint are PCIE terms. PCIE uses a master/slave type arrangement where the root complex is the master and the endpoint is the slave. The C6678 can operate as either the root complex or the endpoint but the TUSB7320 can only operate as a PCIE endpoint. 

    I don't know if there are linux drivers for the TUSB7320. I suggest you post that as a separate question to the forum so that the software team can address it.

    Regards, Bill

  • 0 in reply to Bill Taboada
    Prodigy 60 points

    Thank you very much Bill


    Maurizio