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Communication issue with LTC6813

I am unable to communicate with the LTC6813 IC, what could be the issues?

  • Hi, Shiva

    Please check for the following things in your system.

    • IC supply check
      • V+ should be greater than the required minimum voltage
    • SPI settings check
      • Polarity setting should be high
      • Phase setting should be for 2nd edge
      • Based on Motorola convention POL, PHA can be (0,0) or (1,1)
      • SPI frequency <1MHz or 2MHz depending on the part number
      • Check for Pull-ups on CS (1M), SDO(<10K), and SDI(1M).
      • SPI should be 8 bit
      • MSB first
    • Wake-up test
      • When CS is toggled IC goes into standby state from sleep. Observe Vdrive pin it should be active( ~5V) for 2 seconds after CS goes low.
    • Communication test
      • Whenever BMS IC receives a valid ADC command reference voltage Vref1 and Vref2 turn on to ~3.3V.
      • One can also do WRCFG with REFON =1 and RDCFGA to verify the same bit, and in parallel can check the reference voltage Vref1 and Vref2 for ~3.3V.
    • iso-SPI settings check
      • POL, PHA settings in SW should be the same as on 6820 HW
      • IBIAS voltage should be 2V on BMS IC as well as 6820