Altera Development Code help please

Discussion in 'Programmer's Corner' started by Hurdy, Mar 21, 2007.

  1. Hurdy

    Thread Starter Senior Member

    Feb 27, 2006
    137
    0
    Hi everyone,

    I have been asked to make a sketch of this descriptive code for a Three bit ripple counter, but I can't seem to get my head around it. I am very new to this so all help is appreciated.

    SUBDESIGN RIP3C (Click:INPUT ; Q[2..0]:OUTPUT)

    VARIABLE
    QQ[2..0]DFF ;

    BEGIN
    QQ[2].CLK = QQ[1] ;
    QQ[1].CLK = QQ[0] ;
    QQ[0].CLK = Click;

    QQ[] = NOT QQ[] ;

    Q[] = NOT QQ[];
    END ;

    This is describing a a D-type flip flop but I dont understand what is going on with the inputs and outputs.

    What is QQ? An input to a D-type? then Q my output is the NOT of QQ.

    All help is much appreciated.

    Thank you for your time,

    Rob
     
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