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Coolrunner output pins stuck at 0V

Discussion in 'Electronic Design' started by jvdh, Nov 10, 2005.

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  1. jvdh

    jvdh Guest

    Maybe someone can make a suggestion:

    I'm building a board with a Coolrunner XPLA3384 on it, however, my
    intitial (very very basic) test code is running into problems... The
    device is programmed and verified successfully, but all (configured)
    output pins remain at ground.

    Pins not configured as outputs a pulled up by the internal pullup
    resistors, just as when the device is in an erased state. I'm using
    dedicated JTAG pins to configure the device

    I've checked the power and ground pins, all are looking good, same goes
    for short circuits between the pins and ground...

    I feel I'm missing something small - can anyone perhaps make a
    suggestion on where to look?

    Thanks

    johannes

    http://students.sun.ac.za/~jvdh
     
  2. Andrew Holme

    Andrew Holme Guest

    Does your test code toggle them or just set them high? Might be worth
    trying both.
    Does it work in the simulator?
    Are you using asynchronous set/clear, or global reset?
    Does that device have more than one clock source?

    BTW I'm not familair with the Coolrunner.
     
  3. jvdh

    jvdh Guest

    First I had it running off an input pin (led(0) <= cpdl_ctl(0)), then
    just led <= "01".

    At the moment I'm only using combinatorial logic, so no set/clears,
    global resets or clock sources. Just an ouput...

    Tested code on my Spartan 3 development board - works as expected.

    Thanks for your suggestions!
     
  4. jvdh

    jvdh Guest

    Downloading and installing SP4 from the Xilinx site eventually solved
    my problems...

    johannes
     
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