Class to interface hardware of Touch point IC XPT2046. More...

#include <XPT2046_TS_TFT_LCD_RDL.hpp>

Classes
struct	Touch_Point_t
	Structure representing a touch point on the screen. This structure is used to define a touch area on the screen, x1`and`x2`represent the horizontal boundaries of the touch region. y1` and `y2` represent the vertical boundaries of the touch region. The `id` field is used to uniquely identify the touch point. More...

Public Member Functions
	XPT_2046_RDL ()
	Constructor for class XPT2046_RDL.

rdlib::Return_Codes_e	XPTSPIInit (int device, int channel, int speed, int flags, int gpioDev, uint8_t IRQPin, int8_t resPin)
	Initialise the SPI interface.

bool	XPTIRQIsPressed ()
	Poll the IRQ pin.

rdlib::Return_Codes_e	XPTSPIend (void)
	Stop the SPI interface.

int	XPTReadSensor (int command)
	Read the touch screen sensor Data.

void	XPTReadXY (int xp, int yp)
	Get the X Y position data.

void	XPTInitValues ()
	init values

void	XPTPrintValues ()
	print the touch point values if debug enabled

void	XPTSetPoint (uint16_t x1, uint16_t y1, uint16_t x2, uint16_t y2, uint16_t id)
	Sets the touch points for the XPT_2046 touch controller.

int	XPTGetPoint ()
	Gets the touch point ID based on the current touch coordinates.

Static Public Attributes
static constexpr auto	MaxTouchPoints = 20

static constexpr uint8_t	MAX_LEN_BUFFER = 3

static constexpr uint32_t	DTMAX = 800000

Private Attributes
uint16_t	tpc

uint16_t	tpx

time_t	lsec

suseconds_t	lusec

Touch_Point_t	tps [MaxTouchPoints]

bool	_calibration

int16_t	_min_xp

int16_t	_min_yp

int16_t	_max_xp

int16_t	_max_yp

int16_t	_min_xc

int16_t	_min_yc

int16_t	_max_xc

int16_t	_max_yc

int	_spiDev = 0

int	_spiChan = 1

int	_spiBaud = 50000

int	_spiFlags = 0

int	_spiHandle = 0

int	_DeviceNumGpioChip = 0

int	_GpioHandle = 0

uint8_t	_RESET_PIN = 0

uint8_t	_IRQ_PIN = 0

bool	_resetXPTPinOn = false

Static Private Attributes
static constexpr uint8_t	XPT_START = 0x80

static constexpr uint8_t	XPT_XPOS = 0x50

static constexpr uint8_t	XPT_YPOS = 0x10

static constexpr uint8_t	XPT_8BIT = 0x08

static constexpr uint8_t	XPT_SER = 0x04

static constexpr uint8_t	XPT_DEF = 0x03

Detailed Description

Class to interface hardware of Touch point IC XPT2046.

Member Function Documentation

◆ XPTGetPoint()

int XPT_2046_RDL::XPTGetPoint ( )

Gets the touch point ID based on the current touch coordinates.

This function reads the X and Y touch coordinates, performs a range check, and then scales the coordinates based on predefined minimum and maximum values for both the touch screen and the display. It ensures no double-touch is registered by checking the time between touch events, and returns the ID of the touch point if it lies within the specified touch areas.

Returns: The ID of the touch point if it lies within a valid region, or -1 if no valid touch is detected or double-touch is detected.

◆ XPTIRQIsPressed()

bool XPT_2046_RDL::XPTIRQIsPressed ( )

Poll the IRQ pin.

Returns: true for touchpen down false for pen up

◆ XPTReadSensor()

int XPT_2046_RDL::XPTReadSensor ( int command )

Read the touch screen sensor Data.

Parameters

command the x or y position

Returns: The readbuffer data

◆ XPTReadXY()

void XPT_2046_RDL::XPTReadXY	(	int *	xp,
		int *	yp
	)

Get the X Y position data.

Parameters

xp	the X position
yp	the Y position

◆ XPTSetPoint()

void XPT_2046_RDL::XPTSetPoint	(	uint16_t	x1,
		uint16_t	y1,
		uint16_t	x2,
		uint16_t	y2,
		uint16_t	id
	)

Sets the touch points for the XPT_2046 touch controller.

This function updates the touch point coordinates (x1, y1, x2, y2) and touch point ID (id) for the touch controller. It ensures the coordinates are correctly ordered, swapping values if necessary (i.e., making sure that x1 <= x2 and y1 <= y2). The function then stores the updated values into the tps array at the current tpc index, and increments tpc to move to the next index.

Parameters

x1	The first x-coordinate to set.
y1	The first y-coordinate to set.
x2	The second x-coordinate to set.
y2	The second y-coordinate to set.
id	The identifier for the touch point.

◆ XPTSPIend()

rdlib::Return_Codes_e XPT_2046_RDL::XPTSPIend ( void )

Stop the SPI interface.

Returns

Returns a rdlib::Return_Codes_e

◆ XPTSPIInit()

rdlib::Return_Codes_e XPT_2046_RDL::XPTSPIInit	(	int	device,
		int	channel,
		int	speed,
		int	flags,
		int	gpioDev,
		uint8_t	IRQPin,
		int8_t	resPin
	)

Initialise the SPI interface.

Parameters

device	A SPI device, >= 0.
channel	A SPI channel, >= 0.
speed	The speed of serial communication in bits per second.
flags	The flags may be used to modify the default behaviour. Set to 0(mode 0) for this device.
gpioDev	The device number of a gpiochip.
IRQPin	The GPIO to use for interrupt eg T_IRQ on ili9341 PCB
resPin	GPIO for reset pin MOSI only needed if SPI not already on by TFT set to -1 normally

Returns

Returns a rdlib::Return_Codes_e

Member Data Documentation

◆ _calibration

bool XPT_2046_RDL::_calibration

private

Calibration flag

◆ _DeviceNumGpioChip

int XPT_2046_RDL::_DeviceNumGpioChip = 0

private

The device number of a gpiochip ls /dev/gpio

◆ _GpioHandle

int XPT_2046_RDL::_GpioHandle = 0

private

This holds a handle to a gpiochip device opened by lgGpiochipOpen

◆ _IRQ_PIN

uint8_t XPT_2046_RDL::_IRQ_PIN = 0

private

Interrupt request GPIO pin

◆ _max_xc

int16_t XPT_2046_RDL::_max_xc

private

Maximum x coordinate

◆ _max_xp

int16_t XPT_2046_RDL::_max_xp

private

Maximum xp calibration

◆ _max_yc

int16_t XPT_2046_RDL::_max_yc

private

Maximum y coordinate

◆ _max_yp

int16_t XPT_2046_RDL::_max_yp

private

Maximum yp calibration

◆ _min_xc

int16_t XPT_2046_RDL::_min_xc

private

Minimum x coordinate

◆ _min_xp

int16_t XPT_2046_RDL::_min_xp

private

Minimum xp calibration

◆ _min_yc

int16_t XPT_2046_RDL::_min_yc

private

Minimum y coordinate

◆ _min_yp

int16_t XPT_2046_RDL::_min_yp

private

Minimum yp calibration

◆ _RESET_PIN

uint8_t XPT_2046_RDL::_RESET_PIN = 0

private

Reset pin for SPI

◆ _resetXPTPinOn

bool XPT_2046_RDL::_resetXPTPinOn = false

private

Defines if reset pin is bring used

◆ _spiBaud

int XPT_2046_RDL::_spiBaud = 50000

private

The speed of serial communication in bits per second.

◆ _spiChan

int XPT_2046_RDL::_spiChan = 1

private

A SPI channel, >= 0.

◆ _spiDev

int XPT_2046_RDL::_spiDev = 0

private

A SPI device, >= 0.

◆ _spiFlags

int XPT_2046_RDL::_spiFlags = 0

private

The flags 2 LSB defines SPI mode

◆ _spiHandle

int XPT_2046_RDL::_spiHandle = 0

private

Hold a handle for the SPI device on the channel.

◆ DTMAX

constexpr uint32_t XPT_2046_RDL::DTMAX = 800000

staticconstexpr

Delay 800mS

◆ lsec

time_t XPT_2046_RDL::lsec

private

Last recorded second for touch event timestamp

◆ lusec

suseconds_t XPT_2046_RDL::lusec

private

Last recorded microsecond for touch event timestamp

◆ MAX_LEN_BUFFER

constexpr uint8_t XPT_2046_RDL::MAX_LEN_BUFFER = 3

staticconstexpr

Maximum length of RX and TX buffer

◆ MaxTouchPoints

constexpr auto XPT_2046_RDL::MaxTouchPoints = 20

staticconstexpr

Maximum Number of Touch point's to record

◆ tpc

uint16_t XPT_2046_RDL::tpc

private

Number of touch points stored

◆ tps

Touch_Point_t XPT_2046_RDL::tps[MaxTouchPoints]

private

Array of touch points

◆ tpx

uint16_t XPT_2046_RDL::tpx

private

Maximum number of touch points

◆ XPT_8BIT

constexpr uint8_t XPT_2046_RDL::XPT_8BIT = 0x08

staticconstexprprivate

Mode select 8 bit

◆ XPT_DEF

constexpr uint8_t XPT_2046_RDL::XPT_DEF = 0x03

staticconstexprprivate

Differential Reference Select bit

◆ XPT_SER

constexpr uint8_t XPT_2046_RDL::XPT_SER = 0x04

staticconstexprprivate

Single-Ended Select bit

◆ XPT_START

constexpr uint8_t XPT_2046_RDL::XPT_START = 0x80

staticconstexprprivate

Start bit Control Register

◆ XPT_XPOS

constexpr uint8_t XPT_2046_RDL::XPT_XPOS = 0x50

staticconstexprprivate

A2-A0 Channel select bits for XPOS

◆ XPT_YPOS

constexpr uint8_t XPT_2046_RDL::XPT_YPOS = 0x10

staticconstexprprivate

A2-A0 Channel select bits for YPOS

The documentation for this class was generated from the following files:

Classes

Public Member Functions

Static Public Attributes

Private Attributes

Static Private Attributes

Detailed Description

Member Function Documentation

◆ XPTGetPoint()

◆ XPTIRQIsPressed()

◆ XPTReadSensor()

◆ XPTReadXY()

◆ XPTSetPoint()

◆ XPTSPIend()

◆ XPTSPIInit()

Member Data Documentation

◆ _calibration

◆ _DeviceNumGpioChip

◆ _GpioHandle

◆ _IRQ_PIN

◆ _max_xc

◆ _max_xp

◆ _max_yc

◆ _max_yp

◆ _min_xc

◆ _min_xp

◆ _min_yc

◆ _min_yp

◆ _RESET_PIN

◆ _resetXPTPinOn

◆ _spiBaud

◆ _spiChan

◆ _spiDev

◆ _spiFlags

◆ _spiHandle

◆ DTMAX

◆ lsec

◆ lusec

◆ MAX_LEN_BUFFER

◆ MaxTouchPoints

◆ tpc

◆ tps

◆ tpx

◆ XPT_8BIT

◆ XPT_DEF

◆ XPT_SER

◆ XPT_START

◆ XPT_XPOS

◆ XPT_YPOS