Communication issue with LTC6813

Question

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

Sgarg · Accepted Answer

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)

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Communication issue with LTC6813