mXT143E Xplained multi-touch demo application

#include <asf.h>
#include <stdio.h>

Data Structures
struct	finger
	Struct for touch visualization data. More...

Macros
#define	DISPLAY_COLOR GFX_COLOR_BLACK
	Background color of display. More...

#define	ENABLE_COORDINATE_DISPLAY
	Define to enable display of touch coordinates with each square. More...

#define	ENABLE_TOUCH_SIZE_DISPLAY
	Define to enable resizing of the touch square based on the touch size. More...

#define	MAX_TOUCHES 8
	Maximum number of touches to track. More...

#define	MAXTOUCH_TWI_ADDRESS 0x4a
	Address of the mXT143E on TWI bus. More...

#define	MIN_SQUARE_SIZE 70
	Minimum size of touch squares to draw. More...

Functions
static void	draw_finger_square (const struct finger *draw_finger, const gfx_color_t color)
	Draw square around a finger. More...

static void	get_finger_display_coordinates (const struct mxt_touch_event touch_event, struct finger finger_data)
	Compute display coordinates for touch. More...

int	main (void)
	Main application loop. More...

static void	mxt_handler (struct mxt_device *device)
	Handle maXTouch messages. More...

static void	mxt_init (struct mxt_device *device)
	Set maXTouch configuration. More...

#define DISPLAY_COLOR GFX_COLOR_BLACK

Background color of display.

Referenced by main(), and mxt_handler().

#define ENABLE_COORDINATE_DISPLAY

Define to enable display of touch coordinates with each square.

#define ENABLE_TOUCH_SIZE_DISPLAY

Define to enable resizing of the touch square based on the touch size.

#define MAX_TOUCHES 8

Maximum number of touches to track.

Referenced by mxt_handler().

#define MAXTOUCH_TWI_ADDRESS 0x4a

Address of the mXT143E on TWI bus.

Referenced by mxt_init().

#define MIN_SQUARE_SIZE 70

Minimum size of touch squares to draw.

Referenced by draw_finger_square().

static void draw_finger_square	(	const struct finger *	draw_finger,
		const gfx_color_t	color
	)

static

Draw square around a finger.

This function draws an unfilled square around the specified finger.

Parameters

draw_finger	Pointer to finger struct
color	Color to draw with

References GFX_COLOR_TRANSPARENT, gfx_draw_string(), gfx_generic_draw_rect(), gfx_get_string_bounding_box(), MIN_SQUARE_SIZE, finger::size, sysfont, finger::x, and finger::y.

Referenced by mxt_handler().

static void get_finger_display_coordinates	(	const struct mxt_touch_event *	touch_event,
		struct finger *	finger_data
	)

static

Compute display coordinates for touch.

This function computes the display coordinates for a given touch event, and stores it in the specified X- and Y-coordinate containers.

Parameters

touch_event	Pointer to touch event
finger_data	Pointer to finger struct

References gfx_get_height(), gfx_get_width(), finger::size, mxt_touch_event::size, finger::x, mxt_touch_event::x, finger::y, and mxt_touch_event::y.

Referenced by mxt_handler().

int main ( void )

Main application loop.

This is the main application function, which runs all the initialization code, clears the display and enters a loop in which it continuously polls for new messages from the maXTouch device. If one or more messages are pending, the maXTouch message handler is invoked.

References board_init(), DISPLAY_COLOR, gfx_draw_filled_rect, gfx_get_height(), gfx_get_width(), gfx_init, mxt_handler(), mxt_init(), mxt_is_message_pending(), and sysclk_init().

static void mxt_handler ( struct mxt_device * device )

static

Handle maXTouch messages.

This function handles the maXTouch messages, triggering the drawing of squares around new or moved touches, and removing the squares around released touches.

Parameters

device Pointer to mxt_device struct

References DISPLAY_COLOR, draw_finger_square(), finger::enable, get_finger_display_coordinates(), GFX_COLOR_BLUE, GFX_COLOR_CYAN, GFX_COLOR_GRAY, GFX_COLOR_GREEN, GFX_COLOR_MAGENTA, GFX_COLOR_RED, GFX_COLOR_WHITE, GFX_COLOR_YELLOW, mxt_touch_event::id, MAX_TOUCHES, mxt_is_message_pending(), MXT_MOVE_EVENT, MXT_PRESS_EVENT, mxt_read_touch_event(), MXT_RELEASE_EVENT, mxt_touch_event::status, and STATUS_OK.

static void mxt_init ( struct mxt_device * device )

static

Set maXTouch configuration.

This function writes a set of predefined, optimal maXTouch configuration data to the mXT143E Xplained.

Parameters

device Pointer to mxt_device struct

References Assert, delay_ms, MAXTOUCH_TWI_ADDRESS, MXT_GEN_ACQUISITIONCONFIG_T8, MXT_GEN_COMMANDPROCESSOR_CALIBRATE, MXT_GEN_COMMANDPROCESSOR_RESET, MXT_GEN_COMMANDPROCESSOR_T6, MXT_GEN_POWERCONFIG_T7, mxt_get_object_address(), mxt_init_device(), MXT_PROCG_TOUCHSUPPRESSION_T48, MXT_RESET_TIME, MXT_TOUCH_MULTITOUCHSCREEN_T9, mxt_write_config_object(), mxt_write_config_reg(), twi_options_t::speed, status, STATUS_OK, twi_master_setup(), and UNUSED.

Referenced by main().

Microchip® Advanced Software Framework

Data Structures

Macros

Functions