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Original question:

BQ79600EVM: How can I wake up 79616 through 79600?

BQ79600EVM: 79600 Communication Problem

korcan tuna
Intellectual 315 points
Part Number: BQ79600EVM
Other Parts Discussed in Thread: BQ79600-Q1

Tool/software:

Dear Team,

Bq79600 is used communication with 15 pieces bq79718 and 1 piece bq79731. All ICs are connected to with daisy chain. Sometime happens to communication fault. The fault is 79600 doesn't communie with both bq79731 and 79718.   It should be noted that this fault does not occur consistently; it may manifest on the 50th or 40th attempt. Bq79731 and Bq79718 doesn't response in a time. While the problem is solved by itself, sometimes it requires turning on and off. 

We analyzed the fault. I can share more detail about the fault. BQ79600-Q1 is used to communication with Bq79718 and Bq79731. In the below picture everything works well. Yellow is power(IC power), green is daisy chain communication, blue is Rx pin of MCU and is connected Bq79600, purple is Tx pin of MCU and is connected to bq79600.

If the fault is occured, signal is changed like below picture. Tx is transmitted the data but Rx doesn’t response. During this time daisy chain communication is fault. MCU can not communication with Bq79718 and Bq79731. In this state bq79600 doesn't send fault summary. Bq79600's nfault pin is normal.

What could be the reason for this fault?  Could you help this issue? Thanks for support.

  • 0
    TI__Expert 7000 points

    Korcan,

    How long are you pulling the RX pin low to wake the BQ79600?
    Have you tried sending a HW_RST so you do not need to PWR cycle?

    Have you tried sending more than one wake ping?

    You said that the TX of the MCU is working, but I do not see much data on the TX line of the second picture. 

    It looks like the RX pin is responding to the TX and we see some communication on the VIF. 
    Not sure what is going on exactly but can you be more specific as to what is failing on the communication?

    Best,

         Quentin

  • 0 in reply to Quentin Silic
    Intellectual 315 points

    Hi Quentin,

    Upon zooming in on the image below, it becomes evident that the purple signal is faint, yet the tx(purple) is transmitting data to the bq79600. In this fault state, the MCU is unable to communicate with both the bq79731 and the bq79718. Please note that there are two BQ79600 units. One of the units is configured for 79731 (one piece), while the other is set up for 79718 (fifteen pieces).

    We do not believe that the fault is related to the wake ping, as the failure occurs during the contactor control state or reading the cell voltage, etc. The MCU wakes both 79718 and 79731 and configures both ICs. We have tested the control of the contactors or reading the cell voltage, NTC temperature, etc. in the test sequence and have observed this fault. In this fault state mcu send to tx bq79600 but rx doesn't response as you can see. Btw bq79600's nfault pin don't show the fault summart about bq79600. 

  • 0 in reply to korcan tuna
    TI__Expert 7000 points

    Korcan,

    May I have a block diagram of your setup? I have never seen a case before where someone uses 2x 600s in this way. You should be able to use 1x 600 with the 731 and 718.

    Best,

         Quentin

  • 0 in reply to Quentin Silic
    Intellectual 315 points

    Hello Quentin,

    Could you share your e-mail address? If you do, I can send the block diagram of test set-up.

  • +1 in reply to korcan tuna
    TI__Expert 7000 points

    Korcan,

    q-silic@ti.com. 

    We can close this thread and discuss via email. 

    Best,

         Quentin