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hendwage's avatar
hendwage
Icon for New Contributor rankNew Contributor
4 years ago

Driving internal clock as input on Altera Cyclone II Board.

I'm currently implementing a stopwatch and already have the VHDL code.

I've also set the buttons for start and reset. All that's left is to wire up my clock input which uses a particular frequency and I'm quite lost on how to do that.

I'm using the Altera Cyclone II EP2C35F672C6N board with Quartus Prime 13 and I need to do this without the use of an external clock.

No result comes up on this issue when looking it up online, so I would really appreciate any help I can get on it.

Thanks.

1 Reply

  • EngWei_O_Intel's avatar
    EngWei_O_Intel
    Icon for Frequent Contributor rankFrequent Contributor
    4 years ago

    Hi there

    The internal oscillator is used for initialization of FPGA and is disabled in user mode. It is not supposed to be used to drive user mode logic as there is some variation in the internal oscillator frequency because of the process, temperature, and voltage conditions in Cyclone II devices.

    You can refer to document below for more details.

    https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/cyc2/cyc2_cii5v1.pdf

    I do suggest you to move to later device as most of the Quartus tools doesn't support this device anymore.

    I hereby transition this thread to community support.

    Thanks.