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BQ4050: unknown SMB behavior

Nicholas Carley
Genius 9925 points
Part Number: BQ4050
Other Parts Discussed in Thread: BQSTUDIO

My customer is setting up a system that interacts with the BQ4050 in their system. They have noticed that some of the commands they observe on the bus don't seem to follow the available documentation. For example they are trying to assign serial numbers to the BQ4050, when they use the BQ Studio to assign a serial number of 45 and they sniff the bus they get this long set of commands but can't seem to find where it is the documentation that explains it.

 

0x44 0x22 0x60 0x40 0x35 0x04 0x01 0x23 0x45 0x67 0x00 0x00 0x98 0x6C

0x00 0x00 0x21  0x00 0x45 0x00 0x11 0x54 0x65 0x78 0x61 0x73 0x20 0x49 0x6E 0x73 0x74 0x72 0x75 0x6D 0x65 0x6E 0x45

 

Do you have any additional documentation that explains this behavior?

They're uncomfortable just duplicating this without knowing more.

  • 0
    TI__Genius 10370 points

    Nicholas,

    I am unsure what you mean by assign a serial number? Are they just sweeping SMB block commands to see what responds? 0x44 is our MAC command which unlocks lot of different data depending on what you are trying to access

    Thanks,

    Eric Vos

  • 0 in reply to Vos
    TI__Genius 9925 points

    The main thing we need is the correct procedure for writing to Data Flash memory for the bq4050 using the SMBus protocol. 

    From what I could find, the process is to do a write block to address 0x44 with the desired memory register (0x406e for the Serial Number), followed by the new value (up to one word for Serial Number), and a possible checksum (I found conflicting info on this).

    However, we noticed extra data being passed while using the TI app, so we wanted to check if there is a different procedure.

  • +1 in reply to Nicholas Carley
    TI__Genius 10370 points

    Nicholas,

    Sorry i guess my reply didn't go through prior to me closing the window. the bqStudio extra bytes in the transaction is the length. The packet structure should be

    0x44 (MAC command), 0x04 (length for 2 byte write), 0x60 0x40 (Address 0x4060), 0x00, 0x01 (Data to write 1 in this case)

    Thanks,

    Eric Vos