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MAX10 second PLL issue

hemi
New User
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Hello,

This is my configuration:
Device MAX10 (10M16DCF256C8G)
Quartus Prime Version 24.1std Build 1077

 

I need to use a second PLL, but it is not working. I have tried very hard and read the user manual several times. But without success.
Even with fairly relaxed values: 25 MHz inclk, 25 MHz outclk on the first PLL and 75 MHz on the second PLL.

1) Identical clock source: Both PLLs are controlled by the same pin (CLK0p, PIN_L3, can be used for PLL1 and PLL3).
-> Doesn't work. Only one PLL receives a “locked” signal (PLL1).

 

2) Cascading of PLLs: The first PLL outclk is connected to the second PLL inclk.
-> This does not work either.

 

3) Different clock sources: One PLL is controlled by PIN_L3 (CLK0p), the other by PIN_K6 (CLK1p). Both have 25 MHz, but different sources.
Unfortunately, I can only use these two pins at the moment.
-> Doesn't work either.

 

4) Adding CLKCTRL: I have tried adding CLKCTRL in many combinations, but without success.

 

I am frustrated because it won't work. What am I doing wrong?
Is there a limitation that I haven't recognized yet?

By the way: there is no hint or error message from Quartus.

 

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FvM
Honored Contributor II
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Hi,
I had no problems yet to drive multiple PLLs of MAX10, Cyclone 10 LP and earlier FPGA series from a single clock input. Is it a ready-made evalboard or your own design? Can be that you have either an unstable clock source or a noisy PLL power supply.

Regards
Frank
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