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BQ40Z80: Sleep / Wake making making it impossible to read registers from BQ40Z80 via SMBus

Matthew Bennett
Prodigy 10 points
Part Number: BQ40Z80
Other Parts Discussed in Thread: BQSTUDIO

Tool/software:

I am a software engineer integrating our product externally with a BQ40Z80 over SMBUS / I2C. The battery component is still in development and so I am doing early integraion with a BQ40Z80EVM Evaluation board. I have the cell sensing side set up with a DC power supply and 1k resistor ladder, and I have a 5k resistor across the PACK side to simulate a small load. 

From my own I2C controller, I am able to read registers from the BQ40Z80 via the T.I. Eval board ONLY when / if I use the wake function button on the Eval board. Similarly, when using the BM2400 and T.I. Battery management Studio (bqStudio) I am unable to read anything from i2c except when I 

I am unable to change any of the registers, either, including from TI Battery Studio, possibly because the device is going into sleep mode. 

Please advise on how to wake up the BQ40Z80 over I2C / SMBus or otherwise configure the device so that sleep does not occur in such a way.

  • 0
    TI__Mastermind 28450 points

    Hi Matthew.

    Can you please confirm that the Cell Configuration register is configured to represent the amount of cells being simulated here? You might have to hold the WAKE button until you make this change, however after changing it the gauge should know what voltage to expect from the cell formation and stay awake.

    Regards,

    Anthony