Hi,
I am using ICM-42688 mounted on dev board mikroe-4237 with SPI and it is showing very unexpected behavior when I connect ground pin to the ground. The readout using SPI from registers is very different.
Like when I read WHO_AM_I register with GND pin connected it reads out 0x53 where as data sheet says the default value is 0x47, but if I keep the GND pin floating it reads the correct value (0x47). Same for other registers like INF_CONFIG0 as per datasheet it is supposed to read (0x30) but if GND pin is connected to GND it read (0x21) and if I leave GND pin floating then it reads correct value (0x30).
I have noticed this behavior also when I write a value (0x33) to INF_CONFIG0 register and read this register again with GND pin connected then it reads (0x21) but if I leave GND pin floating it reads the correct value that I have written to it (i.e 0x33).
Same goes to FIFO read if I read with GND pin connected to GND the FIFO reads values for Z-axis like 150.11, 15.90, 9.88, 47.3389, 53.110, 71.9478 very random values, but if I leave GND pin floating it start to read in between 9.81844 or 10.11782.
Is this a normal problem with InvenSense sensors or the issue is with the wiring or is it a requirement to leave the GND pin floating.
Thank you