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CC2541: Flash data is changed

Daniel Fang
Genius 11600 points
Part Number: CC2541

Hi

What situation can change flash data? Such as variation in voltage, ESD or something else?

During mass production programming by Flash programmer. We enabled block debug command but didn't enable write protect.

After ship to market some time later. No programming and Jtag access during this period.

There is 2% out of 5Kpcs flash are changed. We find one flash page is all changed to 0xFF. We are working on comparing more changed flash data.

  • 0
    TI__Guru** 105180 points

    Hello Daniel,

    Some conditions we have observed on customer boards that result in flash corruption / unintentional page erase:

    1. Errant software, such as an application code stack overflow causing the erase sequence to be executed
    2. Exceeding the specified Absolute Maximum Ratings from the data sheet (e.g., ESD)
    3. Not adhering to reference design guidelines for power / clock / ground layout

    Are the devices fully functional after reprogramming?

    Best wishes

  • 0 in reply to JXS
    TI__Genius 11600 points

    Yes, all devices are recovered to working well after reprogramming. 

     Regarding the item 3. Not adhering to reference design guidelines for power 

    1. How about ripply requirement on supply voltage? It 's not mentioned on datasheet. Currently, we test the ripply is ~800 mV.

    2. What's the power supply structure for flash? Is it source from VDD directly or go through a special power system? Thanks.

  • 0
    TI__Genius 11600 points

    Part Number: CC2541

    Continue above topic,  we find there is a small possibility that flash data is not as we expect during mass production programming by flash programmer. 

    1. What's the max ripply limitation of supply voltage? It 's not mentioned on datasheet.

         Currently, the ripply is ~800 mV. Supply by 5V Adapter -> 3,3V LDO, below is ripply photo.

    2. What's the power tree to flash? Is it source from VDD directly or go through a special power system? Thanks.

  • 0 in reply to Daniel Fang
    TI__Guru** 106705 points
    Hi Daniel,

    We are typically quite robust against noise and ripple as the digital circuitry is running off internal LDOs. +/- 800 mV is a lot though. Can you try to reduce that, for example by changing your power source, and see if that resolves the problem?

    I merged your threads by the way.

    Regards,
    Fredrik
  • 0 in reply to Fredrik K
    TI__Genius 11600 points
    Hi Fredrik,

    The problem has been resolved by change power source to constant DC voltage.

    Customer just want to get a explanation why it's failed on adapter.

    If +/- 800 mV is allowed, it shouldn't has problem on +/- 400 mV .
  • 0 in reply to Daniel Fang
    TI__Guru** 106705 points
    Hi Daniel,

    Good to hear that the problem is resolved.

    Regards,
    Fredrik