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Altera_Forum
Honored Contributor I
1,084 Views

Frequency Selection (Clock Multiplexing)

Hello, 

 

I would to like to know a way for selecting one frequency at a time from the output frequencies from an ALTPLL that generates 8 or more different frequencies. 

 

I’m trying to use ALTCLKCTRL but it has a limited number of inputs. I'm using Stratix V FPGA. 

 

So, do you have any suggestions? 

 

Thanks
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4 Replies
Altera_Forum
Honored Contributor I
48 Views

I don't know a way to do this, but could you reconfigure the PLL for eight different frequencies and connect to a single output?

Altera_Forum
Honored Contributor I
48 Views

I need some kind of multiplexing to select a new frequency while the FPGA is still running.

Altera_Forum
Honored Contributor I
48 Views

You can reconfigure the PLL while the FPGA is running.

Altera_Forum
Honored Contributor I
48 Views

Yes, check out PLL reconfiguration. 

 

https://www.altera.com/en_us/pdfs/literature/an/an661.pdf
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