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Original question:

EV2400: BQ76942 and BQ34Z100-G1 sharing I2C bus, can only connect to BQ34Z100-G1

EV2400: bq76952 & bq34z100 on same I2C bus conflict

Kevin Knicker
Expert 1101 points
Part Number: EV2400
Other Parts Discussed in Thread: BQSTUDIO, BQ76952, BQ34Z100,

Tool/software:

TI,

This topic has been covered numerous times, but I am not having success getting it to work:

When the bq76952 and bq34z100 share an I2C bus, bqStudio wants to open the bq34z100 and that leads to issues communicating with the bq76952.

I've followed the steps below several times, but bqStudio still has the bq76952 showing up at address 0xAA and I am getting corrupt data.

Cell voltages are reporting incorrectly and the Data Memory cannot be written to.

Eventually I get a "No acknowledge from device." message in the bottom left corner.

Step followed as shown in the forum posts on how to work around this issue:

  1. Disconnect the 4-pin connector from either the 16S board or the EV-2400
  2. Launch BQ Studio with the EV-2400 connected via USB
  3. When it says no device is detected it asks if you want to connect manually
  4. Choose "Monitor", then choose "Monitor_7695_0_36-bq76952.bqz"
  5. It’ll say it can’t find that device but click “OK”
  6. When it starts the program you can reconnect the I2C cable and it should connect to the BQ76952

Has there been resolution besides trying the steps above?

They have not worked for me.

Thanks,
Kevin

  • 0
    TI__Mastermind 27321 points

    Hello,

    To use bqStudio with BQ76952 and BQ34z100 simultaneously, you will need two independent EV2400s. And, open two independent bqStudio instances. 

  • 0 in reply to Jose Couso
    Expert 1101 points

    Hi Jose,


    I've tried that without any luck.
    From other peoples experience with this, the way to work around this was to follow the steps I have shown in my first post.

    This did not work, however.

    I have no issues with the bq34z100, I just cannot get the bq76952 to communicate first which is what i want to do since bqStudio will always open the bq34z100 first.

    So by following those steps I should be able to establish communication with the bq76952 first, then open another instance of bqStudio using another EV2400 to open the bq34z100.  The bq34z100 opens with no problem.  It's just the bq76952 that reads as shown in my screenshot with erroneous values.

    The solution provided has worked for others, but it is not for me so I was hoping there was a more recent solution. 

    Regards,

    Kevin

  • +1 in reply to Kevin Knicker
    TI__Mastermind 27321 points

    Hi Kevin,

    Why does it say SPI in bqStudio? Are you using SPI communication?

    Are you able to talk to the BQ76952 at all? Not even if using this device alone? 

    There's no other solution than using two instances. These two devices should have different I2C device addresses, so they should not really be fighting on the I2C bus. 

  • 0 in reply to Jose Couso
    Expert 1101 points

    No I'm not using SPI. This is just how it comes up in bqStudio.

     That SPI Config is always there.

    If even shows that window if you look at the images in the bq76952 Evaluation Module set up guide.

    I am able to communicate with the bq76952 with the bq34z100 completely removed.

    However, it comes up showing I2C CRC communication.

    I have to use the SWAP_TO_I2C Command to get it read Data Memory properly.

  • 0 in reply to Kevin Knicker
    Expert 1101 points

    You'll see in the picture that I've boxed in the area that always shows SPI.

    So far it seems to working, but I will need to figure out why having the bq34z100 on the same bus, even though it has the a different address, is causing problems.

    Regards,

    Kevin

  • 0 in reply to Kevin Knicker
    Expert 1101 points

    I'm also curious as to why the bq76952 is defaulting to I2CCRC communication.

    That could be part of my issue.  As I mentioned, I have use the SWAP_TO_I2C Command to do any of value with the Data Memory values.

    Regards,

    Kevin

  • +1 in reply to Kevin Knicker
    Expert 1101 points

    I figured out the I2CCRC thing.  The part I'm using is the bq7695202, which has CRC enabled.

    I created a separate post in regards to whether or not that is causing an issue when also having a bq34z100 on the same I2C bus.

    Thanks,

    Kevin