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Altera_Forum's avatar
Altera_Forum
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9 years ago

How to tie an output pin to '0' or '1' internally using constraints?

Hi All,

How can I define a default (power up) value for the output pin using Quartus-II constraints?

I know I can do so in RTL, but I'd like to do it by constraints.

The pin should drive constant '1'. So, how to tie it internally to '1' by Quartus-II constraint?

Thank you!

1 Reply

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

    You can't make a pin drive logic '1' using a constraint. The best you can do is make all unused pins as inputs with weak internal pullups. Internal pullups will keep the pins high as long as they aren't pulled down or driven low externally. Go to Assignments -> Device -> Device and Pin Options -> Unused Pins.