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BQ76PL455A: BQ76PL455A query

Star Xu
Genius 9645 points
Part Number: BQ76PL455A

Hi

During mass production, individual BQ76PL455A chips return a packet in two parts and appear continuously, resulting in communication errors.

Error data waveforms such as pictures, when the MCU is sent, the data returned by 455A is continuous.

Now in bulk, individual boards appear to return data discontinuity, if the return of two parts of the data stitched together, the data is correct.

Waiting for your reply

Thanks

Star

  • 0
    TI__Genius 9401 points

    Hi Star,

    I didn't fully understand the description. I'll need more details on this to be able to help you:

    • On the waveform above, what are these signals / where are they measured? Please label them. 
    • What command is being sent to the BQ76PL455A-Q1 device?
    • What data does the BQ76PL455A-Q1 device sends back to the MCU? 
    • When you say "error data", what is the exact error that you are seeing on the data? (for example, CRC is incorrect, fault)

    Best regards,

    Leslie

  • 0 in reply to Leslie Marquez
    TI__Genius 9645 points

    Hi Leslie

    Thanks for your reply

    1. The test label is shown in the figure above. The color is consistent with the oscilloscope waveform mentioned above.

    2. Write 0X20 to register 0X02 (single device write and reply)

    3. CHANNELS are configured as 0xFFFF3FE7, and the data are CellVolt0~CellVolt15, AUX0~AUX5, digital chip temperature, analog chip temperature, VDD18, etc

    4. After sending the command, the software delayed 20 ms to check the received data packet. Normally, the complete data packet should be 61 bytes, but only 48 bytes were received.

    The baud rate is configured as 250K and 61 bytes transfer time is 2.5ms.

    Oscilloscope detection: the return data is divided into two reply packets, the first one is 2ms, the second one is 0.5ms, and the interval between the two packets is 12ms.

    Thanks

    Star

  • 0 in reply to Star Xu
    TI__Genius 9401 points

    Hi Star,

    Is there only 1 BQ76PL455A-Q1 device connected in the stack?

    When you say that only 48 bytes were received, is this on the first packet received, and then the rest of the bytes are received 12ms later? Or do you only see 48 bytes total when adding the bytes on the 2 packets?

    Please share the actual data (bytes in hexadecimal) that the MCU is receiving back when there is no error and when there is an error.

    I also recommend to zoom into the actual data in the oscillscope to read the data byte by byte and see what's happening before and after the 12ms interruption in data transmission.

    Regards,

    Leslie