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Altera_Forum's avatar
Altera_Forum
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12 years ago

Setting i/o pins to tri-state mode.

I am a newbie. I am using a board with a Cyclone II, To prevent the board from getting excessively hot, I need to set all I/o pins to tri-state mode. How do I do that?
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

In Quartus, with your project open, go to 'Assignments' -> 'Device'.

Click on 'Device and Pin Options'. In the left tab select 'Unused Pins'.

Reserve all unused pins 'As input tri-stated' - (with or without bus-hold/pull-ups as necessary).

Cyclone II projects seem to default to 'As output driving ground'. Good for noise immunity, not particularly appropriate for development boards.