we are performing accelerometer self test in production tester for measuring performance of sensor.
software flow:
reading x y z axis in 5 samples, clearing FIFO enabling self test. and giving settling time of 20ms delay. then taking 5 samples x y z axis values and disable self-test. averaging values before and after self test values then substracting after and before self test values in each axis. and verifying values weather it's in-between 70 t0 1500 as per datasheet.
some of the modules z-axis difference self test values is zero. ( before self test is 1998)- (after self test is 1998)=zero (not coming between 70 to 1500) declaring as self test is error.
Please let me know is there any change required in logic or is there any problem in chipset self test?
