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BQ3060: Question about communication between BQ3060 and software.

David Kim2
Expert 2700 points
Part Number: BQ3060
Other Parts Discussed in Thread: EV2400, BQEVSW

Hi

My customer asked the following questions.

1. Communication between bq3060 and TI software(BQ gas gauge evolution) is marked as "SMB Terminated VB_I2C_?"  , and communication is not possible.

    Other functions are normal, but only communication is not possible.

    What's the reason?

2. It is a system that communicates i2c with smbus.

    There is a pull-up resistance in i2c, is there a recommended value of resistance?

3. Communication is intermittently interrupted during the low temperature test (-20 ℃).

4. Communication is intermittently disconnected due to USB timeout error.

    What's the cause?


Thanks

  • 0
    TI__Guru 57697 points

    1. The question mark placeholder contains the specific cause of communication error. Infrequent errors are normal in any system

    2. 10K pullups are recommended when communicating with TI EVM. The pullups are already present on EV2300/EV2400. For longer cable or non-TI EVM you may have calculate based on capacitive loading

    3. Intermittent errors are normal. Just retry. When logging from bqEVSW this value will be blank and the next line usually will have a good value

    4. USB timeout can be caused by many reasons like PC hardware, drivers, EV2x00 . Disconnecting and reconnecting EV2X00 is the usual solution. You may also want to load the latest firmware on EV2x00 if you continue to see USB timeout

  • 0 in reply to Shirish
    Expert 2700 points

    Hi Shirish

    Thank you for your answer.

    I have questions as below.

    1. The question mark placeholder contains the specific cause of communication error. Infrequent errors are normal in any system.

        ==> The question mark is unknown. "SMB Terminated VB_I2C_unknown"

    2. 10K pullups are recommended when communicating with TI EVM. The pullups are already present on EV2300/EV2400. For longer cable or non-TI EVM you may have calculate based on capacitive loading

       ==>I am using EV2300.

              I want to test by changing the resistance value of 10k full-up.

              To do so, I need to know the location of the pull-up resistance.

              Can I get the SCH of EV2300 or know the location of the pull-up resistance?

    Thanks

               

  • 0 in reply to David Kim2
    TI__Guru 57697 points

    A VB_I2C_UNKNOWN error is rare and usually is triggered by too much noise on the bus.

    The EV2300 schematic can be found in this document www.ti.com/.../sluu159e.pdf

  • 0 in reply to Shirish
    Expert 2700 points

    Hi Shirish

    I have an additional question.

    We are looking for various causes to improve intermittent communication errors.

    The pull-up resistance in ev2300 was changed from 10k to 4.7k.

    When I change it, I can see more noise like the waveform below.

    Can the noise generated above cause a communication error?

    Thanks

  • 0 in reply to David Kim2
    TI__Guru 57697 points

    Hello David,

    Noise can cause communication errors. Zooming in will show noise more clearly, therefore I am not sure that there is more noise with 4.7K. The time scale is different in the captures.