Why is auto-calibration should always be used in CapSense designs | Cypress Semiconductor
Why is auto-calibration should always be used in CapSense designs
CapSense applications should always have "autocalibration" parameter enabled as this helps in compensating for the PVT (Process, voltage, temperature) variations.
AutoCalibration calibrates the RawCounts to the required percentage of "resolultion" (the percentage is specified in the respective User Module datasheets). This is done whenever the UserModuleInstance_Start() API is called i.e. on every power up of the device.
This ensures that the base RawCount value is same across all the devices irrespective of the variations in IDAC, pin/sensor pad parasitic capacitance, temperature etc and hence also ensures the required sensitivity (provided other user module parameters are selected properly as per the tuning procedure mentioned in the design guides/user module datasheets) for all boards.
If the auto-calibration is not enabled, failures may be seen with some boards due to temperature change/ board to board variations etc.