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BQ78350-R1: Data flash read byte order on SMBus not according to datasheet

Part Number: BQ78350-R1
Other Parts Discussed in Thread: BQ76940, , BQSTUDIO

Hi,

I am implementing a monitoring system that reads data from the BQ78350-R1 BMC (which in turn is connected to a BQ76940 AFE). I need to read some configuration parameters from data flash and it seems that the data arrives in big endian, although the manual (sluubd3c) states the order to be little endian.

Please see the attached communication log when reading the "CUV" setting from the "Protections" block. It has address 0x44CC and is configured to 2850mV (0x0B22) from BQ-Studio.

Is this the expected response or is there a risk of the BMC being configured incorrectly by BQ-Studio (unlikely as it seems)?

Best regards

Emanuel W

  • Hi Emanuel,

    Good news - bqStudio is working as expected! :)

    Since you are reading dataflash, the command, memory address, and memory offset portion of ManufacturerBlockAccess() command is little endian, however, the returned DataFlashAccess() portion is a binary blob starting at the specified memory address and ending at the offset.

    Since a binary blob is being returned from a specific memory address until the specified memory offset, the Data Flash Summary found in Table 19-1 of the TRM ( http://www.ti.com/lit/sluubd3 ) will need to be utilized to determine the values contained within the binary blob with respect to their memory locations.

    When using the other subclass commands (the commands without offsets in DF), the experience should be LE with respect to the data structure being returned.

    Thank you for your report - you're absolutely right, the wording in the TRM should be amended for the sake of clarity.


    Sincerely,
    Bryan Kahler

  • Hi Bryan,

    Thank you for a thorough and quick response. That is good news indeed! :)

    BR,

    Emanuel Wahlqvist