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AGofs's avatar
AGofs
Icon for Occasional Contributor rankOccasional Contributor
5 years ago

Problem with 2 cascaded PLL in CycloneV

Good afternoon,

I'm trying to cascade two PLL's. Every PLL is fractional.

The first PLL gets Clock=75 MHz at its refclk port.

Then, I'm taking the signal from its cascade_out port and connect it to adjpllin port of second PLL.

First PLL gets RESET='0' constant,the second PLL gets RESET from inverted locked port of first PLL.

Unfortunately, nothing happens during simulation -the outputs of second and first PLL are red.

What is wrong with my cascading? Why simulation doesn't work?

4 Replies

  • AGofs's avatar
    AGofs
    Icon for Occasional Contributor rankOccasional Contributor

    Hi guys,

    Do you have something new about this issue?

  • Rahul_S_Intel1's avatar
    Rahul_S_Intel1
    Icon for Frequent Contributor rankFrequent Contributor

    Let me recreate the issue and will update you , in mean time kindly reset the first PLL for some period of time then try to obtain the data