Forum Discussion

Amir21's avatar
Amir21
Icon for New Contributor rankNew Contributor
5 years ago
Solved

How to use "set_clock_groups" properly to constrain 2 asynchronous clocks in different clock domains

Hello, In my project, I have two different clock domains: 1. The first domain use the "sys_clk" from 10[MHz] external oscillator. 2. The second domain use the "pll_clk" (60[MHz]) that generated...
  • ak6dn's avatar
    5 years ago

    Here's what I did. Works as expected.

    create_clock -period 20.0 -name CLOCK_50 [get_ports {CLOCK_50}]

    create_generated_clock -source {pll|altpll_component|pll|inclk[0]} -divide_by 5 -multiply_by 8 -duty_cycle 50 -name CPUCLK {pll|altpll_component|pll|clk[0]}

    create_generated_clock -source {pll|altpll_component|pll|clk[0]} -divide_by 5000 -duty_cycle 50 -name RTCCLK {dk8ea_clock:rtc|rtcclk}

    set_clock_groups -asynchronous -group {CLOCK_50} -group {CPUCLK} -group {RTCCLK} -group {altera_reserved_tck}

    Note you use the NAME of the clock groups in the set_clock_groups command, not the signal or pin names.