Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

Help with ALTPLL Error

Dear list, I have used the MegaWizard Plug-In Manager to instantiate an ALTPLL for my Cyclone II device. At some point in my design I began receiving the following Critical Warning: Critic...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

Yes, exactly. Furthermore, a critical warning is no error. If your input clock source is a crystal oscillator, you can simply ignore it. I think, the reason for the warning is rather simple. Normally, the PLL parameters would allow a symmetric lock range around the nominal frequency. In this case, they don't. But considering the minimum VCO frequency of 300 MHz, 9.9 MHz shouldn't be a problem.