Forum Discussion

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

PLL usage

Hello all, I've noticed that many use PLL on the reference clock input even if they do not need to divide/multiply/shift this clock or do not have external clock to synchronize to the reference fr...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

--- Quote Start ---

Hi,

You could also use the PLL to "free-run" if you suddenly loose the input clock. This might allow your design enough time to enter a safe state. A sudden loss of the clock might leave your design in an unsafe state if it is not accompanied by an asynchronous reset.

Regards,

Niki

--- Quote End ---

Niki,

How to set the PLL in free run mode? Or it execute automatically?

thanks