ASIC functions
§ Offset Calibration: Calibration of capacitive sensor offset
§ Span Calibration Calibration of capacitive sensor span
§ Self test of ASIC（Build in switch capacitance circuit to test the ASIC）
§ Self test of sensor（by applying a voltage to the capacitive accelerometer, the self test function test the integrity of the sensor during field operation
§ Bandwidth adjustment （low pass 500Hz or 2000Hz）, 50Hz with external capacitor
§ Clock Frequency adjustment
