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Intel 80C32

Discussion in 'Electronic Design' started by ee_design, Jul 19, 2006.

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  1. ee_design

    ee_design Guest

    We have an industrial controller which uses an 80C32 cpu. The
    controller has been in production for many many years and is very
    reliable. Intel has announced that they won't make these chips after
    next year. Does anyone have a simple suggestion how to just continue
    with this controller design or is it going to require a re-design with
    new technology?
    Thanks in advance for your opinions and advice.
  2. Just buy the 80C32 (or equivalent) from someone else. You could
    consider a slight redesign to use on-board flash rather than external
    program memory, but that might not be worth it if your quantities are
    small. Test EMC issues carefully before releasing it, in any case.

    Best regards,
    Spehro Pefhany
  3. Eeyore

    Eeyore Guest

    Hardly anyone buys them from Intel any more anyway!

    Are you not aware how widely 'second-sourced' it is ?

  4. Joerg

    Joerg Guest

    Look at Atmel, Philips, Dallas.

    I am not familiar with the C32 but more with the C51. The sole reason
    why I often kept coming back to that old eight-banger was that it is
    about the only processor family that is truly second-sourced. Sometimes
    the firmware gurus said that was like placing an order for a DC-3
    aircraft. But heck, they work (both the C51 and the DC-3).
  5. ee_design

    ee_design Guest

    At one time we bought another brand. Sometimes those acted "spooky"
    while the Intel didn't. It was a simple solution at the time. May be
    time to go bact to someone else. Thanks
  6. ee_design

    ee_design Guest

    My sentiments exactly. It is in an industrial controller, hardly
    cutting edge, and certainly proven that it works. Customer likes that
    feature. "Why fix it if it ain't broken"?
  7. Eeyore

    Eeyore Guest

    That shouldn't happen you know.

    I have recently tended to use the Philips and Atmel flavours.

  8. Joerg

    Joerg Guest

    That could mean that some timing or the reset is running borderline. If
    so it needs to be fixed because even a slight process variation from the
    same vendor could push this product over the cliff.

    Take a look at the reset circuitry. The cheap RC solution that is often
    published in app notes doesn't cut it.
  9. Eeyore

    Eeyore Guest

    It's worked fine for me but I don't rely on the on-chip parasitic diode to avoid
    over-volting the reset input.

  10. Joerg

    Joerg Guest

    Hello Graham,
    The RC scheme can really fall apart when the power supply comes up a bit
    sluggish or goes through a wee brown-out. The worst case is when it
    didn't quite catch a dip and now the uC "kind of" works and behaves like
    a backfiring engine until you power-cycle it. I usually provide my own
    reset so that the uC sees a clean transition.
  11. Eeyore

    Eeyore Guest

    I can see what you mean. The stuff I've designed it into doesn't suffer sluggish power
    rail start-up. In the event of a brown out causing trouble I reckon most ppl would
    cycle the power.

    You've specifically seen this behaviour ?


  12. Also, the R/C reset seems to get flaky as the equipment ages. I had to
    modify a rack full of editing interfaces for VTRs at a TV station
    because the OEM redesigned the circuit and removed the reset circuit the
    board was laid out to use. You do not want to be flipping dozens power
    switches repeatedly when you need to finish editing a tape an hour ago.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  13. Nico Coesel

    Nico Coesel Guest

    Lucky bastard :)) Last time I used the RC reset, I burned my fingers
    badly. Had to pay shipping a device from and to the US. Power your
    circuit with a wall-wart and plug/unplug it quickly. You'll see the uC
    will start to execute code at random without a proper reset circuit.
    Anyway, I've stopped using the 8051 series.
  14. Joerg

    Joerg Guest

    Hello Graham,
    Sure they do but their anger level ratchets up one notch every time that
    happens. Like the way it does when the message appears "Acrobat has
    generated errors..." and the whole PC is shot for minutes.

    Oh yeah, lots. Ripped out many RC "resets" and replaced them with
    something that works. I believe that part of the unreliability in X-10
    powerline gear is also related to that. Will fix it some day but that
    stuff ain't that high on the food chain. My wife wants the east side
    decking repaired first ;-)
  15. Joerg

    Joerg Guest

    Hello Michael,

    Sometimes it does. Once while repairing a piece of (rather expensive)
    equipment I found that they had used a, gasp, electrolytic in the reset.
    This meant the time constant shrunk over time as it dried out until it
    became unbearable. I ripped it out and replaced it with a proper circuit.

    Then there are the electrolytics in the power suplies. When fresh they
    provide enough capacitance to weather a wee notch in the mains supply
    from turning on a big load somewhere. So the RC reset doesn't get
    triggered as much. As these caps age that ability is often reduced and
    the number of hang-ups due to a lousy RC reset can increase.

    As a consultant it's my life, to some extent, to correct other
    engineer's bugs. That's ok, I get paid for it and never spread blame.
    However, when I have to fix rather obvious bugs in equipment that I
    bought as an end user that isn't so nice. It leaving that nagging
    concern about what else might be "sub-optimal" in there.
  16. Joerg

    Joerg Guest

    Hello Nico,
    You can use the 8051 family. Just give them a proper reset, your own
    circuit or a good chip. Even modern uCs such as the MSP430 came out with
    resets that were way too crude for my taste. Now many of them contain
    better resets that can handle brown-outs. I always wonder what on earth
    takes them that long to get it licked.
  17. (Messy) relatively precise (and wide voltage range) analog, created in
    a digital process?

    Best regards,
    Spehro Pefhany
  18. Nico Coesel

    Nico Coesel Guest

    I have other reasons not to use the 8051, the reset is least of the
    'problems' I have with it. You are right about the MSP430. I took me
    some time to figure out why my co-workers had so many problems using a
    USB powered gadget I made which uses the MSP430 as a uC. It turned out
    the USB port of the laptop they used output a surge of a few volts
    which never drops below 0.6 volts after shutting down. Sh*t!
  19. Eeyore

    Eeyore Guest

    Do tell.

  20. Joerg

    Joerg Guest

    Hello Spehro,
    Not really. Many uCs offer superb on-board ADCs, PGAs and whatnot up to
    16 bit precision. Plenty of dynamic range, so the reset can't be rocket
    science. But I guess it plays second fiddle because it doesn't have as
    much marketing glitz as a converter. Or an uncommitted opamp so they can
    it SoC in the ritzy ads.
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