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bq28Z610 I2C communication not working

Pradhan Rivankar
Expert 1080 points
Other Parts Discussed in Thread: BQ28Z610, BQ27742-G1

Dear Sir/Madam

We are evaluating the bq28Z610 battery fuel gauge with our custom board. We want to read and write the data from this IC using the freescale's controller. In our scenario MCU is working as the master and fuel gauge is working as the slave. We connected the SDA and SCL line of this fuel gauge with MCU's SDA and SCL line.

 

We have place the external pull up in SDA AND SCL line.But, We can’t communicate with this chip.

We have also seen the I2C SDA and SCL line wave form on the CRO. From the debugging with CRO, we founded that we are not get ACK pulse on the SDA line. We have attached  schmetic and I2C wave form for your information.

 

We followed the below approaches for the debugging.

1)      We checked with the 100khz, 400kHz clock speed.

2)      We also checked with and without the pull up register.

3)      We also checked with 10 k pull up register.

Please help us to solve this issue.

 

Please let us know if you need more information from the our side.

  • 0
    Expert 1080 points
    Dear Sir/Madam

    Can anyone help to reply me with support on bq28Z610 development.

    Thanks in advance.
    Pradhan
  • 0 in reply to Pradhan Rivankar
    Prodigy 20 points
    I have the same Problem - what might be the reason? any solution?

    Thanks

    Stefan
  • 0 in reply to Stefan Mueller3
    Prodigy 20 points

    Hi again,

    I solved my issue by reducing I²C clock Speed to 100kHz. Although signals were looking good on 400kHz the bq28z610 didn't acknowlege...

    When looking at the pictures from oscilloscope above it seems to me like you are using wrong adress. 0x55 (7 bit adress) needs to be left shifted by 1bit to get 0xAA (7bit adress + r/w bit).

    Best regards

    Stefan

  • 0 in reply to Stefan Mueller3
    Expert 1080 points

    Dear Stefan

    As discussed earlier, the issue we are facing with BQ28Z610 as it works only in the I2C master mode.we want to replace Fuel gauge (for new design) in place of BQ28Z610.

     

    -          BQ28Z610 fuel gauge is the only works in I2C master mode, which is not suitable in our application.

    -          We are searching for new fuel gauge and bq27742-G1  (http://www.ti.com/lit/ds/symlink/bq27742-g1.pdf), which seems suitable for our application.

     

    We have few queries regarding bq27742-G1 fuel gauge as listed below,

     

    1. What is the value of Sense resistor if we are using battery and Solar Panel as below configurations.
      1. Battery – 3.7V, 4600mAH (For Master) & 3.7V, 2200mAH (For Slave)
      2. Solar Panel – 6V, 6W (For Master) & 6V, 3.5W (For Slave)
      3. In Datasheet Page No-31, Typical Application (Table 11), Device Chemistry

    As mentioned in this Point , “Should be configured using TI-supplied Battery Management Studio software”, is there any hardware (EVM) require for that?

    1. Share your valuable views weather bq27742-G1 Fuel gauge seems suitable for our application?

     

    Kindly find attached block diagram of our application.

     

    Please let me know if any other information is require form our end.

     

    I look Forward to hearing from you soon.

    Thanks for understanding.

    Regards

    Pradhan

  • 0 in reply to Pradhan Rivankar
    Expert 1080 points

    Dear Sir/ Madam

    Kindly help to reply on my above query.

    Awaiting for your kind response.

    Thanks and regards

    Pradhan

  • 0 in reply to Stefan Mueller3
    Intellectual 490 points
    This is an old thread, but just to provide the answer for the next person who hits the 100 KHz limit...

    TI pointed me to the "XL" bit in the i2c configuration register. See page 88 in the bq28z610 Technical Reference. The term "i2c" doesn't appear on that page, so I didn't find it searching the documents. After setting that bit, the part works properly at 400 KHz.