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Altera_Forum's avatar
Altera_Forum
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16 years ago

Question about Assignment Editor

Issue: I have system clock connected to pin 90 (dedicated input CLK14) of EPC16Q240. I configured node 'clk_ext' as input in my project and assigned it to pin 90 in assignment editor. Node 'clk_ext' feeds PLL1 input. Therefore I think it is necessary to assign this node to PLL in PLL-section of assignment editor. If I assign node 'clk_ext' to PLL1 in assignment editor then following compilation detects an error 'Can't assign node "clk_ext" to location PLL_1 -- node is type I/O pad'

What I need to do if I want to assign node to PLL?

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

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    Therefore I think it is necessary to assign this node to PLL in PLL-section of assignment editor.

    --- Quote End ---

    It isn't. Simply connect the clock input to a PLL instance. Quartus will automatically select a PLL that has this pin as dedicated clock input. If you need to change this selection for some reason, assign the location to a PLL instance, not to the pin.