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Why my microcontroller hanging?

Discussion in 'Electronic Basics' started by MJDousti, Aug 8, 2003.

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  1. MJDousti

    MJDousti Guest


    I bought Atmel 89C51 (PC model) and I used it on my robot but after a
    few second it stoped working.
    What can I do?
    BTW I have four high current (3A) relays on my circuit.
    I added a bypass capacitor and shunt diode across the coiles of my
    relays and and only one regulator for supply of microcontroller.
    Also insert 2 capacitors (2200 uf, 10 uf) on the between GND and VCC.
    Please help me?
  2. A E

    A E Guest

    You need the Macintosh model.
  3. MJDousti

    MJDousti Guest

    H again,
    My problem is the noise of relays (I think).
    So what is Macintosh model??
  4. Brett

    Brett Guest

    Couldn't it be bad software?
  5. A E

    A E Guest

    It was a joke.
    Look, there's not much we can do over here without a lot more info. But here's
    the three things I *always* check before checking anything else with
    1) Power Supply. Check with a scope. Is it the correct voltage? Does it come up
    fast enough to satisfy the chip's requirements? And when running, are there any
    big spikes that might cause latch up? Any brownouts?
    2) Reset circuit. This is simple, but often overlooked. The reset is usually a
    RC network. Is it generating the correct polarity pulse for long enough? Use a
    scope to check.
    3) Oscillator. Again, this is simple, but often overlooked. Is the oscillator
    starting up quickly enough? Is it at the correct frequency?

    Once all these basic things are in place, then you start more serious debugging.
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