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21615 Discussions

Cyclone V SX Cascading PLL for LVDS

Altera_Forum
Honored Contributor II
1,815 Views

Hi, 

 

I'm currently working on a Cyclone V SX and i've got a little problem regarding LVDS clocking. 

 

I've got a 33 MHZ clock feeding my FPGA from the bottom bank 3A and I want to drive LVDS channels in the Top Bank (8A). 

 

When I use a PLL to generate a 50 MHz to feed an External LVDS PLL, i've got an error message : 

 

Error (12499): Input clock of PLL (...), which drives at least one non-DPA mode SERDES, must be driven by a dedicated clock pin of the PLL. 

 

This is indeed describes in the Cyclone V Clocking Handbook. 

 

Then I tried to feed directly my LVDS PLL with my 33 Mhz clock but the PLL is instantiated in bottom left Factionnal PLL and can't drive LVDS pin in the Top Bank. 

 

I must have missed an option for cascading PLL but i don't see a solution for my problem at the moment. 

 

If someone can give me some light on this problem, i'll be greatly thankful 

 

Thank you
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Altera_Forum
Honored Contributor II
1,033 Views

hi,  

I met the similar error today. While I am using quartus II 13.0sp1 with Arria V. what quartus II version are you using?
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Altera_Forum
Honored Contributor II
1,033 Views

hi glouglou  

 

I got around the problem by using DPA mode.
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Altera_Forum
Honored Contributor II
1,033 Views

Hi, Thanks for you help 

 

I'm currently using 13.0sp1. Unfortunately there is no DPA support in Cyclone V i think.
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Altera_Forum
Honored Contributor II
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I am wondering if it is a bug with 13.0sp1 because I don't have this error with 13.0 on previous project.  

 

I will test with 13.0 when I have time.
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