Datasheet

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER
DS41393B-page 38 Preliminary  2009-2012 Microchip Technology Inc.
9.3.4 CALIBRATE – 0x14
Enter Calibration mode. This instructs the controller to
enter a mode of accepting the next four touches as the
calibration point coordinates. See Section 10.1 “Cali-
bration of Touch Sensor with Controller” for an
example.
Completion of Calibration mode will automatically store
the calibration point coordinates in on-board controller
memory and set (to 1) the CCE bit of the TouchOptions
register. This bit enables the controller to report touch
coordinates that have been processed with the
previously collected calibration data.
To provide for proper touch orientation, the four
sequential calibration touches must be input in the
physical order on the touch sensor, as shown in
Figure 9-1.
FIGURE 9-1: CALIBRATION ROUTINE
SEQUENCE
Upon completion, the controller’s register values and
calibration data are stored to the EEPROM.
The Calibration mode will be cancelled by sending any
command before the mode has been completed. If the
calibration is canceled, the controller response may
appear incorrect or incomplete. This is expected
behavior.
Touch Sensor
#1
#2
#4
#3
Upper Left
Upper Right
Lower RightLower Left