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SKon1
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5 years ago

"derive_pll_clocks" doesn't create generated clocks properly

"derive_pll_clocks" doesn't create generated clocks properly

Hello,

In my Arria V design. I have a PLL with one input and 3 outputs. The input is 125 MHz. The outputs are as follows:

1. Output 0 - 125 MHz ( without phase shift - with properties identical to the input clock ).

2. Output 1 - 125 MHz ( without phase shift - with properties identical to the input clock ).

3. Output 2 - 25 MHz.

In Timequest I run "derive_pll_clocks" and look at the output of the command.

I was expecting to see 3 "create_generated_clock" - but I only see one. Only the output for the 3rd clock ( 25 MHz ) has a "create_generated_clock" command.

Why is that ?

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