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Altera_Forum
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10 years ago

can cyclone V pll be feeded with global I/O pin clock

Hi Sadly i got clock routed to non dedicated pin. I want to use pll in cyclone V device to get desired frequencies from it. Then i connect clock to pll i got the following error: The PLL refe...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
10 years ago

Sorry to be the bearer of bad news, but you can only feed PLLs from the dedicated clock inputs.

If you can add a loop to your board, from a spare I/O pin to a (hopefully free) dedicated clock input, you should be able to get something working. Route the clock you want out of the spare I/O pin so that, via your new loop, it feeds the dedicated clock pin. Note: this will add a little jitter but, assuming your mod is tidy, not enough to stop the PLL working.

Cheers,

Alex