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RE: [cosmacelf] Re: Hex keypad

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  • Bob Armstrong
    ... Ah, but you also need logic to generate a key pressed strobe, and to debounce the keypresses at the same time. Bob [Non-text portions of this message
    Message 1 of 82 , Feb 4, 2012
      >Another approach is to use a pair of 1-of-8 priority encoders (74xx148
      >or 4532). It also uses a keypad with one common. Each key connects to
      >one input of a priority encoder. The EI and EO pins daisy-chain to
      >produce a 4-bit output that is the hex value of the highest-number key
      >pressed.

      Ah, but you also need logic to generate a "key pressed" strobe, and to
      debounce the keypresses at the same time.

      Bob



      [Non-text portions of this message have been removed]
    • Mark Graybill
      But...but... It s =upside-down!= ... The look is _really good_. It s 1976 all over again. :) Mark Graybill ... http://saundby.com/ Electronics, Books, Video
      Message 82 of 82 , Feb 14, 2012
        But...but...

        It's =upside-down!=

        :D

        The look is _really good_. It's 1976 all over again. :)

        Mark Graybill
        ---------------------------------------------------------------
        http://saundby.com/
        Electronics, Books, Video Games, etc.

        On Feb 14, 2012, at 1:03 PM, rarecoinbuyer wrote:

        >
        >
        > --- In cosmacelf@yahoogroups.com, "urrossum@..." <mark@...> wrote:
        >
        > > OK, an even better one from the same source:
        > >
        > > http://www.mpja.com/Keypad-16-Button-X-Y-Black/productinfo/18317+SW/
        > >
        > > It's already labelled with the 16 hex digits, and I find it a bit more attractive. Manufactured by Grayhill, and still $4.95.
        > > --
        > > Mark
        > >
        >
        > That's perfect and it is even RCA blue.
        >
        >



        [Non-text portions of this message have been removed]
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