Hello,
There is a data transfer error issue. I checked the waveform at pins which are pin 3, pin 4, pin 5 and pin 12.
Pin 3(yellow) is CS signal from MPU. Pin 4(blue) is CLK of SPI. Pin 5(purple) is DATA out of SPI. PIN12(green) is ADC DATA of SPI.
Pin 5(ch3) and pin 12(Ch4) should be almost identical but the second bit of data became mismatch. This waveform is probed ISO7331 pins.
Why this kind of thing happens?
Best regards,
Toshihiro Watanabe