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- Connect a controller board to the BMS carrier.
- Connect two oscilloscope probes; one between GND and IP and one between GND and IN. Set the oscilloscope to output IP - INa logic analyzer to IP, IN, and GND.
- Supply 12 V between GND and 12 V.
- Set the CS pin of the LTC6820 being tested low, set MOSI to 0, set MOSI to 1, and then set CS high again. The latching edge of the clock will change for different SPI modes. Current sense is SPI mode 1 (clock idles low, latches data on falling edge) and the AFEs are SPI mode 3 (clock idles high, latches data on rising edge).
- If the LTC6820 is functioning, there will be a long -1 pulse transmitted between IP and IN, followed by a short -1 pulse, short +1 pulse, and then a long +1 pulse. A -1 pulse is when IN switches high before IP. A +1 pulse is when IP switches high before IN.
- Repeat for each SPI.
- Turn off the power supply.
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