count_down

        // Counter Down
        if(started==1 && counter==0 )
        begin
            if(digit1 > 0)
                    digit1 = digit1-1;
            else
            begin
                digit1 = 9;
                if(digit2 > 0)
                    digit2 = digit2-1;
                else
                    digit2 = 0;
            end
        end

        // Counter Up
        if(started==1 && counter==0 )
        begin
                if(digit1 < 9)
                    digit1 = digit1+1;
                else
                begin
                    digit1 = 0;
                    if(digit2 < 9)
                        digit2 = digit2+1;
                    else
                        digit2 = 0;
                end
        end