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MSP430F449: MSP only working after 8 secs

Poh Kok Keng
Genius 5512 points

Part Number: MSP430F449

Tool/software:

hi support,

I had a strange issue here and below is the partial schematic and hope you can advice what when wrong? 

1. Under normal operation, the LED can shows charaters immediately after power on. 

2. the suspected MSP unit can only show the charaters after 8 secs. 

Do you suspect is the contacts issue? oscillator issue? or some watchdog reset issue? 

Best regards,

KPk

  • 0
    TI__Mastermind 30505 points

    Hey KPk,

    8 seconds is a long time.  The only thing that I could image could hold the device that long and then allow it to still work correctly is maybe the oscillator.  

    I see you have a crystal on the board, I image that the code waits for this crystal signal to stabilize before moving on?  I image it gets stuck there.  

    Is this happening at room temperature?  When I've seen slow oscillating start issues, it's usually at very low temperatures.

    Thanks,

    JD  

  • 0 in reply to JD Crutchfield
    Genius 5512 points

    hi JD,

    The oscilator MPN# used is AWSCR-4.00CP-T4. can you help to check the spec if this meet the requirement?

    We have replaced the crystal before replacing the MCU to several units, but it didn’t improve. Then we changed the MCU and it became good/normal. And we have performed ABA swapped the good became slow when first power on.

    Yes, this’s tested at room temperature. 

    Any other advice?

    Best Regards,

    KPk

     

     

     

  • 0 in reply to Poh Kok Keng
    TI__Mastermind 30505 points

    Hey KPK,

    When you did the ABA test, are you saying that the issue followed the board and not the chip?   

    Also, the part number you provided seems to be for your 4MHz oscillator, but with an 8-second start-up time, I would be way more suspicious of the 32kHz crystal.  I think even in good conditions those can sometimes take a couple hundred ms to stabilize.  

    We do have an app note on MSP430 32kHz crystal oscillators.   It touches upon everything from crystal selection, choosing the right load caps, layout, and even testing to find our your circuits Safety Factor.  Take a look.  

    Thanks,

    JD

  • 0 in reply to JD Crutchfield
    Genius 5512 points

    hi JD,

    The 32.768Khz crystal used is ABS07-32.768KHZ-T

    Description : CRYSTAL 32.768KHz 12.5pF SMD
    MPN : ABRACON
    MFG : ABS07-32.768KHZ-T
    MCU used is MSP430F449IPZR
    When I check on the capacitance value, it seems like the it is not following the table recommended below. Will this affect the start up timing and causing the 8s delay? Do you suggest to change it? 

    Best Rgds, KPK

  • 0 in reply to Poh Kok Keng
    Genius 5512 points
    Hi JD,
    Pertaining to this issue, I would like to inform you, we already use part from TI since a few years back and so far was no issue.
    Date Code 2332, total received qty: 13,000 pcs was no defect found.
    Date Code 2336, total received qty: 7,000 pcs also was no defect found.
     
    Only when start using Date Code 2343 & Date Code 2344, then we found the failure.
    FYI:
    • Date Code 2343, the failure rate is 1.43% (200 pcs defect from 14,000pcs)
    • Date Code 2344, we already running production for about 5,000pcs and already found 259pcs defect (defect rate: 5%). And now, we still have balance qty: about 2,000pcs to run.
     
    From this failure, we are not confidence to use Date Code 2402 in our stock (total qty: 13,000 pcs). 
    We also would like to send some defect sample to Manufacture for failure analysis. will you suggest to go for FA request? 
    Best regards
    Felix 

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