AR1000 Datasheet, PDF (23/37 Pages) Microchip Technology – Resistive Touch Screen Controller

7.15.3 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 Calibration 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 pre-collected calibration data.
The “calibration” mode will be cancelled by sending any command before the mode has been completed.
Send : <0x55><0x02><0x14><Calibration Type>
Calibration Type Description
0x04
4 point
Receive
: <0x55><0x02><Response><0x14>
<0x55><0x02><Response><0x14>
<0x55><0x02><Response><0x14>
<0x55><0x02><Response><0x14>
<0x55><0x02><Response><0x14>
for initial command response
for response to 1^st target touch release
for response to 2^nd target touch release
for response to 3^rd target touch release
for response to 4^th target touch release
To provide for proper touch orientation, the four sequential calibration touches must be input in the following
physical order on the touch sensor.
#1
Upper Left
#2
Upper Right
Touch Sensor
#4
Lower Left
#3
Lower Right
© 2009 Microchip Technology, Inc.
DS41393A-Page 19