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BQ76972: 0x60 checksum and 0x61 data length

Amber Si
Intellectual 2155 points
Part Number: BQ76972

Tool/software:

Hi team,

e2e.ti.com/.../bq76952-question-about-buffer-length

I want read data memory with checksum, and I found a e2e which has talked about 0x61 data length ---When reading from the data memory, the transfer buffer will be filled with 32-bytes of data beginning at the address the read was initiated at---that means 0x61 will be always 0x24, right?

and if so, Is that will affect the calculation result of checksum if the actual buffer data length is only one byte?

BR

Amber

  • 0
    TI__Genius 17835 points

    Hello Amber,

    The previous post you found actually answered this question, however, maybe I can help reword it/clarify.

    The transfer buffer will always be filled with 32 bytes beginning at the address the read was initiated. If you are reading/writing to any of the data memory addresses as stated in Table 13-37. Data Memory Table of the BQ76972 Technical Reference Manual (TRM), the length should be 36 bytes or 0x24, even if the actual data you are grabbing or care about is only taking up 1 byte of the 32 bytes in the transfer buffer.

    The calculation for the checksum should only be needed when you are writing to the data memory, not reading to it. Checksum is calculated based on the address and data from 0x3E, 0x3F, and the buffer data. It doesn’t include the checksum in 0x60. This is explained more with an example in Section 13.1 Data Memory Access of the TRM.

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    TI__Intellectual 2155 points
    Alexis_H said:
    when you are reading the data memory, not writing to it

    Hi Alexis,

    I think checksum is only use when I need write data to data memory. right?

    BR

    Amber

  • 0 in reply to Amber Si
    TI__Genius 17835 points

    Hello Amber,

    Amber Si said:
    I think checksum is only use when I need write data to data memory. right?

    That is correct. Apologies for the typo. I have corrected that sentence in my reply above. 

    Best Regards,
    Alexis