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Altera_Forum
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11 years ago

cyclone 3 PLL[1..4]_CLKOUTp

Hello to all! I'm reading the "Pin Connection Guidelines" for cyclone3 and cyclone4E. In cyclone3 doc i read : "These pins can only use the differential I/O standard if it is being fed by a P...
Altera_Forum's avatar
Altera_Forum
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11 years ago

You will be able to use both clkoutp & clkoutn as independent general purpose, single ended I/O.

Can I assume you want to drive clkoutp from the PLL?

Yes, you should be able to both drive clkoutp (as a single ended signal) from the PLL and use clkoutn as a general purpose I/O pin.

I've just tried this, successfully, albeit with a Cyclone IV part - I don't have Cyclone III installed. It will quite happily allow me to use clkoutn as an input or output signal whilst using clkoutp as a single ended PLL output signal.

Put a small project together and let Quartus give you the answer for Cyclone III.

Cheers,

Alex