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bq34z100 extended data command programming

Krishna Kakarla
Prodigy 30 points

Hello All,

I plan to use the bq34z100 with a 6S LiPo pack but I'm really confused about how to configure the design capacity, design energy and the terminate voltage for my application. It would be really helpful if someone walks me through the steps involved in accessing and change the extended data flash commands. What I understood from one of the examples given in the datasheet was that:

1) In order to access a specific data class, the subclass ID must be passed to the DataFlashClass() register at 0x3e. For example 0x50(80) for the Gas gauging application.

2)Next I pass 0x01 to DataFlashBlock() register located at 0x3f and then subsequently write the Blockdata() based on the offset calculation.

3)Now what I don't understand is, that the offset here is taken as 48(on pg 14 of the datasheet) but looks like the offset is 67 mentioned on pg 42.

Have I misunderstood the concept here.?

Thanks,

Regards,

Krishna

  • 0
    Intellectual 300 points

    Krishna,

    I think that's a documentation error. In my version of slsua1b (revised Dec. 2012), the text on p.14 states:

    For example, to access Terminate Voltage in the Gas Gauging class, DataFlashClass() is issued 80 (0x50) to set the class. Because the offset is 48, it must reside in the second 32-byte block.

    As you point out, Cell Terminate Voltage is listed in Table 20 (p.42) as having offset 67.

    TI makes several different gas gauges, and may have recycled the text on p.14 from the documentation of a different chip. They might have corrected the text in a more recent version of the document. 

    I would use the value from Table 20.