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    BMI270 CHIP ID reported as 0x26 instead of 0x24

    BMI270 CHIP ID reported as 0x26 instead of 0x24

    New Poster


    I had received a new order of product containing a BMI270.  For some reason, my BMI270-Sensor-API based code that was running perfectly fine on a previous build of that same product fails at the CHIP ID check in the bmi270_init.  It is returning 0x26 instead of 0x24.

    I had thought that it was speed related since it's off by one bit, so I tried changing the SPI speed.  I tried several speeds from 400kHz - 8MHz but all gave the same result.  I modified the CHIP ID check code to also accept 0x26 and this allowed the structure to be initialized.  Furthermore, the subsequent calls to the BMI2 library return a BMI2_OK.  However, it doesn't seem to actually work or at least the interrupts don't seem to fire.  Again, the exact same binary working as expected on batch of product.

    Examined the chip and found that the markings on the "working" BMI270 says "5L-U4K" (may be an "O" instead of a "U").  The "non-working" BMI270 says "5N-OKC".  See attached pictures.  So finally, took the chip from the working board and reflowed onto the new board.  Suddenly works.

    Anyway, kind of long-winded but questions are:
    1) What is the "5N-OKC" chip?  What product do you have that reports CHIP ID as 0x26?  My hope is that you simply sent the wrong but footprint compatible part to my CM.

    2) If it is an IMU type chip, can you please provide some documentation for it so I can make the appropriate changes to the software?  I have 350 of a 400 unit batch that was built probably from the same reel.  I would prefer to just make a software change to fix this.  Please don't tell me that these are just defective BMI270 chips.  I don't really have the time, nor can I afford to have all these units reworked.



    7 REPLIES 7

    Community Moderator
    Community Moderator

    Hello ArchJoeD,

    0x26 is the chid ID of BMI220.
    As you bought chip from thirty party, you can check it with them if they provided correct stock to you.
    It is also recommended to purchase chips from official channels to track the chip information. If you buy from a third party, we don't know what happened to the middle process.

    Occasional Visitor

    The "5N-OKC" marking on the BMI270 chip seems unusual, and it's likely not a standard identifier for the BMI270 model. Typically, BMI270 chips should have markings indicating their specific model and revision. The fact that it reports a CHIP ID of 0x26 instead of the expected 0x24 further suggests that it might not be a BMI270 or it could be a different variant or revision.

    Without more information, it's difficult to determine exactly what the "5N-OKC" chip is. It's possible that there was a mix-up or an error in sending the correct chips to your contract manufacturer (CM). I would recommend reaching out to your chip supplier or manufacturer to inquire about the "5N-OKC" chips and verify if they indeed sent the correct parts.

    If the "5N-OKC" chip is indeed an IMU-type chip and you need documentation to make the appropriate software changes, you'll need to identify the specific model or variant of the chip. Once you have that information, you can request documentation from the chip manufacturer or supplier. This documentation should include datasheets, application notes, and other relevant technical information that will help you modify your software accordingly.

    In the meantime, since reflowing the chips from the working boards onto the new boards resolved the issue, it's possible that there might be some inconsistency or problem with the "5N-OKC" chips themselves. However, before concluding that, it's essential to verify the identity of these chips and gather more information from your supplier or manufacturer.

    Community Moderator
    Community Moderator

    Yes, before concluding that, it's essential to verify the identity of these chips and gather more information from your supplier.