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s002wjh's avatar
s002wjh
Icon for New Contributor rankNew Contributor
5 years ago

internal osc & global clk

is there way to get the internal osc on cyclone 3 or 4 use the global clk network? if so whats the .qsf command for that? i think the 80mhz internal osc is not using the global clk network.

3 Replies

    • s002wjh's avatar
      s002wjh
      Icon for New Contributor rankNew Contributor

      so if timing my constraint is like this

      create_clock -name "div2_clk" -period 25.000 [get_registers {frequency_divider:frequency_divider_inst|clk_div2}]


      create_generated_clock -divide_by 2 -source [get_registers {frequency_divider:frequency_divider_inst|clk_div2}] -name div4_clk [get_registers {frequency_divider:frequency_divider_inst|clk_div4}]

      do i need write something like this? for global clk network? i divide the internal osc by 4

      set_location_assignment CLKCTRL_G2 -to "get_registers {frequency_divider:frequency_divider_inst|clk_div4}~clkctrl"

  • SyafieqS's avatar
    SyafieqS
    Icon for Super Contributor rankSuper Contributor

    Hi Wen,


    May I know if the KDB given able to assign the internal oscillator to GCLK? Alternatively, in assignment editor, you can select global signal and assign global clock to the osc and you can reflect in your qsf.