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Keystone II K2E PCIe0 SerDes input clock

Glyn Jones
Prodigy 100 points

I'm running the Keystone II standalone (ie not connected to a chassis).

I intend to connect PCI devices using the AMC connector.

The schematics show that the SerDes input clock for PCIe0 is provided through a multiplexer - either using the AMC refclock on pins 80/81, or the output of the clock generator 2 (U17, pins 20/21).

I want to use the internal clock, so configure the multiplexer using the "pcie 1" command on the BMC console.

However, a scope shows the clock generator pins 20/21 are consistently set high, with no clock output on them.

Is there a BMC command that will configure the clock generator to turn on the clock?

If not, how can I get it running?

  • 0
    TI__Mastermind 46460 points

    Glyn,

    Please double-check your tests.  Operating the PCIe from the local clock is the standard use case.  All EVMs are tested for this fuctionality prior to shipment from the factory.  You should not need to do anything to have this clock generated and provided through the mux.

    Tom

     

  • 0
    TI__Mastermind 42545 points

    Hi Glyn,

    The PCIECLK from U17 should be enabled and selected by default. Do you see the clock when the board is first enabled? Is the clock present if the board is powered on the bench?

    Regards, Bill

  • 0 in reply to Bill Taboada
    Prodigy 100 points

    Hi Bill,

         I'm powering the board standalone with nothing connected to the AMC connector.

    I've verified I'm reading Chip U65 by checking the printing on the chip as well as the U65 printed next to it.

    The clock inputs on pins 2-3 are 0V (as expected - they are connected to the AMC connector).

    The clock inputs on pins 5-6 are both showing DC at 500mV.

    The mux output follows the inputs when I toggle it using the BMC "pcie" command.

    There do not appear to be any clock outputs on either the U17 or U18. I'm looking at the P and N outputs for all the clocks described in the schematic, and they are all DC at ~2.5V.

  • 0 in reply to Glyn Jones
    TI__Mastermind 42545 points
    Hi Glyn,
    Sorry for the late reply. If you are not seeing any clocks on U17 and U18 than the board must not be operating correctly. I'm assuming that you can't connect with JTAG and that the board isn't showing any signs of operation. You should contact eInfochips to discuss returning the defective board.
    Regards, Bill