Forum Discussion

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

Max 10 clock divider

I am using the internal oscillator in the max10, and wondering whats the best way to divide it down. I looked into using a PLL for this but that doesn't seem to be possible. Is there any better app...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
9 years ago

Hi,

I went through the same thing. I think you are misreading the datasheet, like I did at first. The datasheet is simply saying that the internal oscillator is guaranteed to be *somewhere in the range* of 55-116MHz. There is no way to set it- you get what frequency you get from the factory, somewhere in that range. In my experience, it is usually right in the middle of that range, which is what I think you are seeing, too. I know the IP says something about setting the frequency, but it's misleading. You can't.

So your design must be really tolerant of different clock speeds! :)

If you want to slow it down at all, I would use a counter, and grab whatever bit output you need to get the frequency desired. Remember that even then, it's frequency will be proportional to the variation of the internal oscillator.

One bright spot is that (as far as I know, I could be wrong!) the internal oscillator frequency will stay at whatever frequency it comes at. I don't think it will drift over time.

HTH

Robert