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Altera_Forum
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14 years ago

Cascading PLLs Cyclone II

Hey guys, I recently bought a MorphIC-II board that comes with a Cyclone II FPGA (EP2C5F256C8). I am trying to cascade two PLLs in my design. When I try to compile it I always get this err...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

Yes. The only pins that can drive the PLL are physical pins, there is no internal routing that drives the input to the PLL.

So to do this you must drive the clock to a pin (preferably one of the dedicated PLL outputs) the wire it to one of the dedicated inputs of the next PLL.