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Altera_Forum's avatar
Altera_Forum
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13 years ago

finding process operating on falling edge

Hi,

in one design I am working on Quartus assumes transitions between rising and falling edges of one PLL clock, making life harder timing-wise.

To my understanding, the reason why he would assume and find such transitions is the fact that somewhere in the design some process uses the falling edge of that clock (am I right?).

Is there a way to find out - in TimeQuest - where the data is launched on the falling edge?

The design is large, coding conventions (clock names, etc) are a disaster and "grep"-ing the design didn't bring me the process...

Thanks!

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    Run "Report Clock Transfers" to see numbers on all types of transfers(rr is rising edge to rising edge, rf is rising to falling, etc.). For specific paths, you can do:

    report_timing -setup -npaths 200 -detail full_path -rise_from * -fall_to * -panel_name "200 rise to fall transfers"

    This just shows rise to fall, regardless of clock. You coul also do:

    report_timing -setup -npaths 200 -detail full_path -rise_from_clock SRC_CLK -fall_to_clock DST_CLK -panel_name "rise of SRC_CLK to fall of DST_CLK"

    This will do it for specific clocks. You can combine these, do different rise/fall variations,etc.