This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DM642 reset problem when system power on/off quickly

Dear Sir,

 

Our product is installed on an automotive environment.

Currently, we meet a problem with DM642 DSP reset.

When we turn on and turn off our system power repeatedly & quickly and the last power state remains on, but our system does not boot as normal.

But when we push our hardware reset button to re-trigger the reset pin of DSP DM642, the system can boot normally.

 

Why the DM642 DSP can not boot normally when the power state change rapidly?

What can we do to avoid the problem?

Really appreciate your help!!

Best Regards,

Eric Fang

 

  • Eric Fang said:
    Why the DM642 DSP can not boot normally when the power state change rapidly?
    What can we do to avoid the problem?

    Does the voltage go all the way to 0 at the power pins of the DM642 when you do this? Does your board have a power supervisor circuit to reset in low voltage conditions? My initial suspicion would be that your power supply is not going off entirely in time for when you turn it back on leaving the DSP in a indeterminate undervolted state.

  • I had meet a problem.

    Reset dm642 quickly and more

    dm642 will not work,even reset it again and again

    i watch the signal in sdram bus.

    the signal hold half of 3.3V or less

    in this state , reset dsp has no effect

    why?

    this problem will prensent in many devices

  • We have a very similar problem.

    After every  power up we reset the DM642 as part of a watchdog test.

    Occasionally after the reset release, the DM642 won't work.

    The DM642 is configured to boot from FLASH.

    After reset release the DM642 sends reading command over EMIF to the FLASH and the FLASH send data over EMIF to the DSP.

    When the DM642 fails we see that the FLASH is sending boot data but the EMIF data bus is stuck on '0' so when FLASH sends 3.3V the actual data that the DSP see is 1.8V and thus the DM642 won't boot.

    In this state resetting the DSP has no effect the only way to recover is to turn power down.

    This problem was noticed on many devices.

    Do you have similar problems?

    how did you manage this problem?