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BQ76PL356A SPI communication

He Zihui
Prodigy 45 points
Other Parts Discussed in Thread: BQ76PL536EVM-3

Hello.

I used  4 cascaded BQ to monitor 20 cells. 

I designed the board according the schematic diagram of the bq76pl536EVM-3 and the layout was almost as same as EVM-3.

The problem is my master chip can only communicate with the first BQ through the spi, the others do not respond to the address discovery and assignement algorithm.

In my design, the port FAULT_H,ALERT_H,DRDY_H and CONV_H were not used.And the CONV_H was connected to VSS. 

Did I do something wrong?  Could you give me some suggest.

Thanks!

 

  • 0
    TI__Genius 10785 points

    Hi Zihui,

    Please check HSEL pin. Go check out TIDA00821 design reference from TI product

    Make sure HSEL is connected to LDOD for slave ICs.

  • 0 in reply to Roger Hwang
    Prodigy 45 points

    Hello Roger,

    I checked slave ICs HSEL pin and I'm sure they were respectively been connected to the LDOD pin. The following figure is the waveform of the 1st (host)and  2nd(slave) BQ HSEL pin.

    I measured the waveform of other pins for the 1st BQ, but I don't know whether these signals are normal or not. Could you please help me to analyze them?

    Thank you！

  • 0 in reply to He Zihui
    TI__Genius 10785 points

    thanks for your plots.

    Is it possible for me to review your schematic?

    Questions for you.

    1. Are you using TI GUI or your own F/W?

    2. Have you address your devices? Master should have device address 01. Or, you can't even address the slave devices. You MUST have proper device address before you can communicate properly.


    Send me your schematic then I can have a quick review.

    Send me your email address then I can contact you separately.

    Or, request me as your friend then we can have private discussion.

  • 0 in reply to Roger Hwang
    Prodigy 45 points

    Roger,

    Thank you so much for your patience.

    1.I used my own F/W. And the software is based on the demo code of the slaa478.

    2.I tried to address the devices, the 1st BQ was addressed 01 and 2nd BQ was not take respond to the address discovery and assignment algorithm.

    Here is my email address. 142440319@st.usst.edu.cn

    I am very appreciate if you can review my schematic.

    Regards,

     

  • 0 in reply to He Zihui
    TI__Genius 10785 points
    Ok. I will send email to you and reply back with your schematic.