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BQ76940: I2C no response

Timsen
Expert 1660 points
Part Number: BQ76940

Dear all：

     BQ7694003 Measured REGOUT = 3.3 V.Cap1 - VSS cap2-VC5X cap3-VC10X are all 3.28v.But I2C has not been successfully communicated, and AFE does not respond on SDA, as shown in the figure below.Communication time should be sufficient.

What is the reason for this?

Is the device damaged?

  • 0
    TI__Guru* 81034 points
    Hi Timsen,

    Do you have pullup resistors on the I2C lines? The I2C address is 7 bits (see Figure 7-4 of datasheet) and the address is 0x08 for this device number.

    Best regards,
    Matt
  • 0 in reply to Matt Sunna
    Expert 1660 points

    Hi Matt：

         There is pull up resistance, the device number is 0x08

    Other measured data:
    alert footer outputs 3.3V; BAT-VC10X:16V; VC10X-VC5X:16V; VC5X-VSS:20V
    REGSRC: 19V; CHG, DSG:0V

    But I2C no response？why？

    The following is the waveform on I2C oscilloscope. Is it correct?

    • The following is the waveform on I2C oscilloscope. Is it correct?

  • 0 in reply to Timsen
    TI__Guru* 81034 points
    Hi Timsen,

    From the waveform it looks like you are writing the address 0x0000100, which would be 0x04. This device has a 7-bit address, but I think you may be trying to use 8 bits?

    Matt