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Small PLD for interrupt flag register

Discussion in 'Electronic Design' started by [email protected], Oct 20, 2007.

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  1. Guest

    Hi guys.

    Just wondering whether someone could suggest a small PLD which would
    be able to fit my design for a 16-bit wide interrupt flag register.
    I'm hoping for a DIP package, but I suppose PLCC will do. Not keen on
    hand soldering surface mount.

    The design consists of 16 input pins going into the J inputs of 16 JK
    flip flops. K inputs are unused. The 16 Q outputs go to a 16-1 mux
    whose single output goes to an output pin. The 16 CLR inputs go to a
    1-16 demux whose enable input goes to an input pin. The select lines
    of the mux & demux are connected and brought to 4 input pins. Finally
    the 16 input pins also go to a 16 input OR gate whose output goes to
    an output pin.
  2. Guest

    Too many output blocks for a small pld but your design is easily
    splittable so you could get it into two 22v10 dips.
  3. Uwe Bonnes

    Uwe Bonnes Guest

    For small task a XC9536XL comes handy, is in circuit reprogrammable and
    below 1 Euro. Why stil bother with PLDs?
  4. Ben Jackson

    Ben Jackson Guest

    Any small CPLD will probably do. Download either Xilinx's WebPack
    or Altera's Quartus II web edition and implement your design. You
    can do it with schematic capture exactly from your description. It
    will then tell you what CPLD will fit the design (probably the
    smallest possible thing, like an XC9536 or EPM3064).

    PLCC pins are wider, but I'd rather put down a TQFP which keeps the
    pins where I can see them. If you bridge a TQFP pin, it's easy to
    fix with solder wick. If you bridge a PLCC pin it can be a huge pain
    in the ass.
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