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82450 UART

Discussion in 'Electronic Components' started by toa, Nov 1, 2004.

  1. toa

    toa Guest

    Does anyone here know if the 82450 is pin-compatible with the 16450? If not,
    does anyone know where I can find a data sheet?

    Thanks
     
  2. When I use google to search for 82c450 it looks like it's a video card chip.

    Rune Christensen
     
  3. toa

    toa Guest

    Unfortunately, a video chip set has the same name, which of course adds to
    the confusion. I've googled quite a bit around for this, and found several
    references to the 82450 UART, but none that provides a data sheet, nor any
    that assert or dissert pinout compatibility with the apparently better known
    16450.

    The strongest proof for the 82450 being a UART chip, is that I found one on
    the RS232-card of my old 386 computer, which I am about to cannibalise to
    make some control circuitry.


    -Top poster, and proud of it
     
  4. The key is to go the other way, and look at 'history'. All these UART
    chips, are latter (compatible) descendents of the original 8250. This was
    the UART used in the original IBM PC, which because of the high interrupt
    latency on PC's, and on latter machines, timing problems with interfacing
    to the AT bus, showed communication overrun problems. Hence versions were
    produced with slightly improved timing spec's to make them perform better
    in these applications.
    The 8250, was originally a WD part, and the 82450, was the first
    descendent of this. Latter the 16450, increased the maximum operating
    speed, and switched to CMOS fabrication. This came out very soon after the
    82450, and hence the former largely disappeared, soon after it's launch.
    UMC in Taiwan, were still making the 82450, quite recently, but most
    modern motherboards, have 16450/550 derivatives 'built in' to the chipset
    instead, reducing demand for these chips a lot. The datasheet for the
    82450, is basically identical to that for the 8250, with slight timing
    changes. The 16450, was followed by the 16550, with even larger FIFO
    buffers.

    Best Wishes
     
  5. Dave Platt

    Dave Platt Guest

    The strongest proof for the 82450 being a UART chip, is that I found one on
    One entry in the netbsd-help archives states that "82450 and 16450 are
    for all practical purposes, identical."
     
  6. toa

    toa Guest

    Great help - thanks a lot, all of you! :)
     
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