All the demos that feature a resistive touch screen can be calibrated. Some demos have AR1020 resistive touch screen controller support. Please see the AR1020 setup below for more information.

The calibration sequence is the same for all hardware configurations and touch screen methods (internal resistive or AR1020).

1. At the start of the application, after reset, have the center of the screen pressed for about one second.

2. After a second, the touch screen will display the calibration sequence and instructions will appear on the screen.

a. The calibration sequence is a four point system that is the same for internal resistive and AR1020.

3. After calibration, the application will continue with the application code.

The calibration sequence is also automatically entered without the specified sequence above if the touch driver detects that the touch driver version stored in the target non-volatile memory does not match the expected value. This typically means there no valid calibration value is stored.

Internal Resistive Touch Screen Controller

The internal resistive touch screen controller (software based) is supported by all graphics demos. All hardware profile header files default to this touch screen controller unless identified in the file name.

When using the internal resistive touch screen controller with the PIC24FJ256DA210 Development Board, set jumper JP9 and JP10 on the PIC24FJ256DA210 Development Board to position 1-2.

AR1020 Touch Screen Controller

On two display boards, 5.7″ VGA Truly TFT Display Board (AC164127-8) and 7.0″ WVGA Truly TFT Display Board (AC164127-9), the AR1020 touch screen controller is provided as a touch screen option. The user can select between the internal or AR1020 touch screen controller by setting jumper bank on these display boards. Setting the jumper bank to MCU will set the touch controller to internal. Setting the jumper bank to AR1020 will set the touch controller to AR1020.

Two demos support the AR1020 touch screen controller, Object Layer Palette and S1D13517. The Configs folder in each demo will have a hardware profile with AR1020 in the name to designate that the AR1020 controller is used in the configuration. Select the appropriate hardware profile for the touch option used.

When using AR1020 with the PIC24FJ256DA210 Development Board, set jumper JP9 and JP10 on the PIC24FJ256DA210 Development Board to position 2-3.