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MPC850 - Intermittent Machine Check Exception

Discussion in 'Embedded' started by Dave P., Jul 21, 2003.

  1. Dave P.

    Dave P. Guest

    Has anyone had any experience with intermittent machine check
    exceptions on the MPC850 ?
    According to the MPC850's registers it fails on one particular
    instruction fetch (to SDRAM using UPMA) which is called by a branch
    However our test equipment shows that it never gets to this
    instruction fetch as there is a phantom attempted transfer on the bus
    with a non existent address and a TS* issued but no chip selects –
    this phantom transfer times out after the bus monitor time due to no
    TA* - causing a machine check

    Note that this code usually runs fine and only fails occasionally

    I've checked through the Chip Errata but can't find anything that
    relates to this problem

    Anyone got any ideas or know what could be causing the phantom

    Thanks in anticipation
    Dave P.
    Dave P., Jul 21, 2003
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  2. Dave P.

    Wayne Guest

    I'm still pretty new to this but what about the watchdog timer and bus
    Those my not cause the machine check exceptions but I thought I would just
    through this out
    since I had problems with these.

    Wayne, Jul 21, 2003
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