XPT2046 Touch Library for any platform!

This is a touch library for XPT2046 IC used for resistive touch screens. XPT2046 is a very popular touch controller IC and can be found in regular LCD displays that are used in embedded systems projects.

• This library is (mostly) platform-independent.
• Hardware specific calls are seperated from main library.
• Very easy to add any hardware platform support by providing a few function definitions and macro definitions that are called/used by this library.

How to Add Platform Supports:

Adding platform support is super easy! Go to the generic_template directory and read platform_generic.h and platform_generic.c files there. You need to implement the functions and macros given there. That's all! Those functions and macros are called by this library.

So, create platform_<name_of_platform>.c and platform_<name_of_platform>.h files with all the mandatory functions and macros. After creating your own platform files based on the template, add an entry to the platform_select.h file. When using your newly created platform, simply uncomment that entry in the platform_select.h and comment out the rest.

Note: Your main application only needs to include xpt2046.h file and not the platform files.

How to Use:

1. Select your platform in platform_select.h file by uncommenting the target platform and commenting out the rest.
2. Include xpt2046.h in the main application.
3. Define extern global variables that are used by your platform files, in your main application.
4. (optional) Call xpt2046_calibrate_touch() if you are running it for the first time. Store the parameters in an array and use it for the consecutive builds/runs.
5. Call xpt2046_get_touch() to get calibrated and filtered touch position data.
6. Enjoy!

API:

// Get raw x,y ADC values from touch controller
uint8_t  xpt2046_get_touch_raw(uint16_t *x, uint16_t *y);

// Get raw z (i.e. pressure) ADC value from touch controller
uint16_t xpt2046_get_touch_raw_z(void);

// Convert raw x,y values to calibrated and correctly rotated screen coordinates
void     xpt2046_convert_raw_xy(uint16_t *x, uint16_t *y);

// Get the screen touch coordinates, returns true if screen has been touched
// if the touch coordinates are off screen then x and y are not updated
// The returned value can be treated as a bool type, false or 0 means touch not detected
// In future the function may return an 8 "quality" (jitter) value.
uint8_t  xpt2046_get_touch(uint16_t *x, uint16_t *y);

// Run screen calibration and test, writes calibration values to passed array of 5 elements
// Arg must be an array of 5 items (e.g. uint16_t params[5])
void     xpt2046_calibrate_touch(uint16_t data[5]);

// Set the screen calibration values
// Arg must be an array of 5 items (e.g. uint16_t params[5])
void     xpt2046_set_touch(uint16_t data[5]);

// Set touch threshold to detect touch
void     xpt2046_set_touch_threshold(uint16_t threshold);

Tests:

This library is tested on following platforms so far:

SDK/Platform	RTOS	Devkit/EVK/Board	MCU Family	Platform Dir
ModusToolbox	None	CY8CKIT-062S2-43012	PSoC6	platforms/modustoolbox_psoc6
nRF Connect	Zephyr	nRF52840-DK	nRF52	platforms/nrfconnectsdk_zephyr_nrf52

See generic_template to see how to add your platform.