Forum Discussion

s002wjh's avatar
s002wjh
Icon for New Contributor rankNew Contributor
4 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.
  • s002wjh's avatar
    s002wjh
    Icon for New Contributor rankNew Contributor
    4 years ago

    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"