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Altera_Forum's avatar
Altera_Forum
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14 years ago

I/O Pin voltage

Hello,

I am trying to design a simple multiplexer using the Cyclone III FPGA on the DE0 board. I am using the PLL to divide the 50MHz on board clock down to the appropriate speed. However whenever I try to put a signal out to one of the I/O pins, it is only about 20mV peak to peak. I understand the pins on the DE0 board should put out 3.3V. I have the pins assigned to the 3.3V standard in the Quartus II pin planner, but it doesn't seem to make any difference. Any help would be appreciated.

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    You can try the following steps to set the output voltage:

    Menu : Assignments -> Device -> Device and Pin Options

    In Voltage Tab you can choose 3.3V LVTTL for Default I/O Standard.

    Then don't forget compile your project.

    I also use DE0 board and every time I use the default voltage.

    I hope it can help you.