General touch driver

Collaboration diagram for General touch driver:

Data Structures
struct	touch_point
	Panel coordinate and measurement data of a single touch. More...
struct	touch_calibration_matrix
	Calibration matrix coefficients. More...
struct	touch_event
	Contains touch event type and touch point data. More...
Modules
	4-wire resistive touch driver general implementation
	Board-specific ADC control for resistive touch driver
Defines
#define	TOUCH_NR_CALIBRATION_POINTS 3
	Number of calibration points needed for driver.
Typedefs
typedef struct touch_point	touch_calibration_points_t [TOUCH_NR_CALIBRATION_POINTS]
	Array to hold calibration points.
typedef void(*	touch_event_handler_t )(const struct touch_event *event)
	Pointer to touch event handler function.
Enumerations
enum	touch_event_types
	Enumeration of different touch event types for the touch_event struct. More...
Functions
void	touch_init (void)
	Initialize the touch driver.
void	touch_enable (void)
	Enable touch detection and sampling.
void	touch_disable (void)
	Disable touch detection and sampling.
void	touch_get_event (struct touch_event *buffer)
	Get last detected touch event from driver to buffer.
bool	touch_is_touched (void)
	Return current state of touch driver.
void	touch_set_calibration_matrix (const struct touch_calibration_matrix *matrix)
	Assign a calibration matrix to the driver.
void	touch_get_calibration_matrix (struct touch_calibration_matrix *buffer)
	Copy calibration matrix from driver to a buffer.
void	touch_compute_calibration_matrix (const touch_calibration_points_t points, struct touch_calibration_matrix *matrix)
	Compute a calibration matrix.
void	touch_set_event_handler (touch_event_handler_t handler)
	Set touch event handler for driver.
touch_event_handler_t	touch_get_event_handler (void)
	Get current touch event handler from driver.

Detailed Description

For resistive touch the driver implementation utilizes GPIO pin interrupts, if needed, for touch detection and the ADC for position measurements.
If CONFIG_SOFTIRQ is defined, the driver will make use of the soft IRQ with ID SOFTIRQ_TOUCH_PROCESS for processing of measurements and calling the current touch event handler function.

Precondition:

For 4-wire resistive touch with XMEGA, the driver needs the following configuration symbols to be defined:

CONFIG_TOUCH_PORT_BASE
CONFIG_TOUCH_PORT_IRQ_ID
CONFIG_TOUCH_PORT_INTLVL
CONFIG_TOUCH_ADC_IRQ_ID
CONFIG_TOUCH_ADC_INTLVL
CONFIG_TOUCH_ADC_PRP
CONFIG_TOUCH_XL_PIN
CONFIG_TOUCH_XR_PIN
CONFIG_TOUCH_YD_PIN
CONFIG_TOUCH_YU_PIN
CONFIG_TOUCH_OVERSAMPLING

Note:: See pin configuration for details on which pins are driven low or high during touch measurements.

Define Documentation

#define TOUCH_NR_CALIBRATION_POINTS 3

Number of calibration points needed for driver.

Definition at line 176 of file touch.h.

Typedef Documentation

typedef struct touch_point touch_calibration_points_t[TOUCH_NR_CALIBRATION_POINTS]

Array to hold calibration points.

Meant for use with touch_compute_calibration_matrix().

Definition at line 183 of file touch.h.

typedef void(* touch_event_handler_t)(const struct touch_event *event)

Pointer to touch event handler function.

Definition at line 219 of file touch.h.

Enumeration Type Documentation

enum touch_event_types

Enumeration of different touch event types for the touch_event struct.

Definition at line 203 of file touch.h.

Function Documentation

void touch_compute_calibration_matrix	(	const touch_calibration_points_t	points,
		struct touch_calibration_matrix *	matrix
	)

Compute a calibration matrix.

Computes the calibration matrix that is used to get the panel coordinates from raw measurements of the touch surface.
This requires that the

Note:: Reference: http://www.embedded.com/story/OEG20020529S0046

Parameters:

	points	Pointer to array containing calibration points.
	matrix	Pointer to storage buffer for the calibration matrix.

Definition at line 270 of file touch.c.

References touch_calibration_matrix::a, assert, touch_calibration_matrix::b, touch_calibration_matrix::c, touch_calibration_matrix::d, touch_calibration_matrix::e, touch_calibration_matrix::f, and touch_calibration_matrix::k.

Referenced by touch_calibrate_task_handler().

void touch_disable ( void )

Disable touch detection and sampling.

Disables interrupts for the GPIO and the ADC.

Definition at line 160 of file touch.c.

References cpu_irq_restore(), cpu_irq_save(), touch_priv_adc_disable_int(), and touch_priv_port_disable_int().

Referenced by touch_init().

void touch_enable ( void )

Enable touch detection and sampling.

Resets the driver and touch state, configures GPIO pins for touch detection and enables interrupts for GPIO and the ADC.

Definition at line 137 of file touch.c.

References touch_last_event, TOUCH_NOT_TOUCHED, touch_priv_adc_clear_int_flag(), touch_priv_adc_enable_int(), touch_priv_port_clear_int_flag(), touch_priv_port_enable_int(), touch_priv_port_set_detection(), touch_state, and touch_event::type.

void touch_get_calibration_matrix ( struct touch_calibration_matrix * buffer )

Copy calibration matrix from driver to a buffer.

Parameters:

buffer

Address of buffer to copy calibration matrix to.

Definition at line 250 of file touch.c.

References assert, and touch_matrix.

void touch_get_event ( struct touch_event * buffer )

Get last detected touch event from driver to buffer.

Parameters:

buffer

Buffer to store touch event in.

Definition at line 179 of file touch.c.

References assert, cpu_irq_restore(), cpu_irq_save(), and touch_last_event.

touch_event_handler_t touch_get_event_handler ( void )

Get current touch event handler from driver.

Returns:: Address of the currently set handler function.

Definition at line 226 of file touch.c.

References touch_event_handler.

void touch_init ( void )

Initialize the touch driver.

Initializes the GPIO pins and ADC for touch detection and measurements, as well as the driver states.
Must be called before any other function in this driver.