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LP8764-Q1: the PMIC either goes blank or does not power up after a "re-programming + power cycle"

Mahdi Saghaleini
Prodigy 40 points
Part Number: LP8764-Q1


Tool/software:

We have 3x instances of this LP8764 PMIC on our board, and we can do the re-programming through either the PMIC EVM, or through I2C writings. This issue shows up when we use I2C programming, and the PMIC either goes blank or does not power up after a "re-programming + power cycle". Then when we try to communicate with the PMIC through the EVM, it is easily detectable, and even when we compare the contents of the PMIC with the original config file, they match! Then we can reprogram it and it powers up with no issues. In all the above steps, the exact same program config file is used. Now the questions are:

1- what items could be different in the PMIC that even comparing the contents of the failed pmic with the original config file does not show them, yet re-programming the pmic makes it power up? Are there items that might be different in hidden and cannot be detected by the config file comparison?

2- Can any thing lead to the PMIC I2C path become defective in the process of prgramming? If yes, how can it be corrected by using an EVM?

  • 0
    TI__Mastermind 18030 points

    Hi Mahdi,

    You mean when PMIC is reprogrammed (using GUI) through EVM. It gets programmed correctly and the device powers up. Whereas when it is programmed via I2C writings (Also elaborate what is this I2C system, are you using assembly or binary file to re-program), device doesn't programmed correctly. 

    To me it looks the other method (through I2C writings) is not correctly programming the device. How that needs to be implemented is documented in following user guide.

    https://www.ti.com/lit/pdf/slvaf93 

    Is my understanding correct? Please also share related information that could be helpful.

    BR,

    Ishtiaque

  • 0 in reply to Ishtiaque Panhwar
    Prodigy 40 points

    hi Ishtiaque,

    To clarify, we have implemented the I2C programming method using the binary file based on the user guide, and it has been working fine for the past few months for so many cases. The above issue has showed up recently, and it is not consistent, meaning that roughly from every 5 times that we try the I2C method, one of them shows this issue. and what adds to the mystery is that when we use the GUI to compare the contents of the PMIC with the original config file, it shows they match 100%. We are trying to understand what should have changed here, and particularly what could have made the pmic not to power up, while the GUI shows its contents matches the original config file 100%?

  • 0 in reply to Mahdi Saghaleini
    TI__Mastermind 18030 points

    Hi Mahdi,

    Thanks for clarification and making it more clear. 

    Let's consider you tried reprogramming the device 3 times in a row

    1. 2 times it went through successfully with certain configurations lets call it A NVM. 
    2. 3rd time when you are programming. it causes the issue as you have explained above. Does this third time, you tried same A config NVM that got failed or you did some changes and got become B NVM? 
      1. If so what is it that you are changing? Have you looked at it? 

    I cannot say what might have changed but could this be I2C programming setup that is sometimes not working correctly? you may try to have look at that as well.

    Regards,

    Ishtiaque

  • 0 in reply to Ishtiaque Panhwar
    Prodigy 40 points

    hi Ishtiaque,

    In all of my explanations, I'm referring to a single config file with no changes at all.

  • 0 in reply to Mahdi Saghaleini
    TI__Mastermind 18030 points

    Hi Mahdi,

    Thanks for that information. It is strange but to me it looks like there is something with I2C programming setup.

    One way could be to compare the communication waveforms with I2C programming method and the one with GUI programming. 

    I think you mentioned that with GUI programming you do not get any issues, right? please confirm, so then clearly it is something with I2C programming setup which is working but sometimes does this random error. Please debug the workflow and see step by step that everything is correctly implemented. 

    Regards,

    Ishtiaque