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Original question:

RESET pin always low...!!!! (msp430f2274)

MSP430F2274: RESET pin always low

Marty Scherzer
Prodigy 50 points
Part Number: MSP430F2274


I have been using the MSP430F22774 for a few years now and have had no issues with it.  I recently received 4 modules back that had an issue with the reset pin being held Low.  The pin has a 10K ohm pullup resistor on it.  Much larger than the 47K that is recommended.  There is no capacitor.  If I plug in the programmer or if I use a pullup around 470 ohms, it pulls the pin to a high level and everything works fine.  The supply voltage to the chip is 3.0 vdc

I currently have about 400 of these modules in use without a problem and how I have 4 with the same problem.

Thank you 

  • 0
    TI__Genius 10860 points
    Hi Marty,

    this is an odd behavior. Is it possible that the device is in SBW mode and thus the RST pin is currently configured as output?
    You could try pulling the TEST pin to GND and see if the behaviour of RST comes back to normal.
    This would indicate that the problem is due to SBW mode configuration.

    Please let me know the test results.
    Thanks and best regards,
    Britta
  • 0 in reply to Britta Ruelander
    Prodigy 50 points

    Britta,

    Thank you for the response.  I did find the issue.  It was external to the processor.  I found the reset button had contamination in it and was holding the pin low.  I could not see this issue with an ohmmeter.  It showed around 200k ohms., but removing the button made everything work.  I disassembled the button and found the contamination.  I replaced the button on all 4 modules and they all are functioning now.

    Thanks for your help

    Marty 

      

  • 0 in reply to Marty Scherzer
    TI__Genius 10860 points
    Hi Marty,

    thanks for your feedback.
    I'm glad you've solved the issue!

    Regards,
    Britta
  • 0 in reply to Marty Scherzer
    Genius 3850 points

    " I could not see this issue with an ohmmeter.  It showed around 200k ohms., but removing the button made everything work"

    that's some magic buttons: at 200k, they can pull a 10k resistor low. 

    save them for future scientists to study.

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