1 Reply Latest reply on Dec 3, 2010 1:47 PM by salomo.murtonen

    Latching events

    rob.lowe

      Hi Guys,

         

      I have need to latch an event, I thought this would be very simple but it is putting up quite a fight! Firstly I tried to make an RS type flip flop from two NOR gates, this refused to latch at all for some reason. I am guessing the async logic is synthesized by use of sync-subcomponents? Anyhow, it really didn't want to play.

         

       So, I tried to hook up a D type flip flop and turn the clock off by means of an AND gate and the negated output of the d-type. (As attached) This seemed to work, right up to the point where I connected the D-type output to the clock input so again it looks like some kinda race condition.

         

       I need a fast acting latch, that I can reset. any ideas? It seemed such a simple bit of the circuit...

         

      Rob