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Original question:

BQ78Z100: Battery Management Studio (bQStudio) Supported Targets

BQ78Z100: I2C Address and Communication

AG
Prodigy 125 points
Part Number: BQ78Z100
Other Parts Discussed in Thread: BQSTUDIO, , EV2400

Tool/software:

Hi TI,

Searching the E2E forums, it appears the address is 0xAA (or 0x55 without the read/write bit). I've a BQ78Z100 that I'm able to communicate with via BQSTUDIO and an EV2400, but cannot see the device when performing a 7-bit I2C scan. Can see other devices on the I2C bus, but nothing shows for the BQ78Z100. My device is sealed from the manufacturer, not sure if that has anything to do with it. Is there anything specific to a sealed BQ78Z100 that needs to be done to see it via I2C?

  • 0
    TI__Mastermind 33781 points

    Hello AG,

    This is a pretty strange behavior, I just want to confirm that you are in fact able to communicate with the device?

    Regards,

    Adrian

  • 0 in reply to Adrian
    Prodigy 125 points

    Hi Adrian,

    I am able to communicate with the device (per my update in the other E2E post), see screenshot below for BQStudio screenshot. Have been able to access commands such as unsealing, shutting down, and updating the data flash memory, just can't see it on my system when performing an I2C sweep.

  • 0 in reply to AG
    TI__Mastermind 33781 points

    Hello AG,

    I have been able to access commands like that using our other gauges.

    When you execute one of these commands, do you see the corresponding behavior happen in BQStudio? 

    Regards,

    Adrian

  • 0 in reply to Adrian
    Prodigy 125 points

    Hi Adrian,

    Yes, I see BQStudio make updates after making those commands, such as updating the data flash memory and then committing a read to observe that yes my update went thru.

  • 0 in reply to AG
    TI__Mastermind 33781 points

    Hello AG,

    So it seems that the gauge is working and behaving properly, so I am not sure why your 7-bit scan of the I2C lines does not show the address, you can try to use another application to view the I2C comm lines (I personally use a saleae). 

    Regards,

    Adrian

  • 0 in reply to Adrian
    Prodigy 125 points

    Hi Adrian,

    Using that device, does the address show up as the 10-bit 0xAA or 7-bit 0x55?

  • 0 in reply to AG
    TI__Mastermind 33781 points

    The address shows up as 0x55.

    Regards,

    Adrian

  • 0 in reply to Adrian
    Prodigy 125 points

    Hi Adrian,

    Good to know! Using the Aardvark and Total Phase's Control Center Application (a device used for another TI EVM), I'm able to begin communication with the device at 0x55 address, but only when I set the I2C speed to 100KHz. When set at 400Khz, I receive no response when querying a read at 0x00.

    Still trying to make sense of the data I can read at address 0x00, but for what reason could it work at 100Khz but not 400Khz? Datasheet indicates operation for fast modes, not sure what's causing it not to operate at that rate.

  • 0 in reply to AG
    TI__Mastermind 33781 points

    Hello AG,

    400Khz is not guaranteed to work when the gauge is in firmware mode. 400Khz mode should only be used when programming the device with no firmware.

    Regards,

    Adrian

  • 0 in reply to Adrian
    Prodigy 125 points

    Hi Adrian,

    Just to make sure I'm on the same page: firmware mode means when the device has firmware programmed onto it already? Meaning once the device has firmware on it, only communicate with it at 100Khz for I2C?

  • +1 in reply to AG
    TI__Mastermind 33781 points

    Hello AG,

    Yes, firmware mode means that firmware is already programmed on the gauge. Once it has firmware on it, then it is recommended to only communicate with the device at 100Khz.

    Regards,

    Adrian