Getting Started with LvGL Part 3: Touch Integration

#ifndef SPI2_H_
#define SPI2_H_


#include "stdint.h"

void SPI2_Pins_Init(void);
void SPI2_Init(void);
void SPI2_TX(uint8_t *data,uint32_t size);
void SPI2_RX (uint8_t * data, uint8_t length);




#endif /* SPI2_H_ */

#include "SPI2.h"
#include "stm32f7xx.h"



#define SPI2_AF 0x05


void SPI2_Pins_Init(void)
{
	RCC->AHB1ENR|=RCC_AHB1ENR_GPIOBEN|RCC_AHB1ENR_GPIOCEN;

	GPIOB->MODER|=GPIO_MODER_MODER13_1|GPIO_MODER_MODER15_1;
	GPIOB->MODER&=~(GPIO_MODER_MODER13_0|GPIO_MODER_MODER15_0);

	GPIOB->OSPEEDR|=GPIO_OSPEEDR_OSPEEDR15|GPIO_OSPEEDR_OSPEEDR13;

	GPIOB->AFR[1]|=(SPI2_AF<<GPIO_AFRH_AFRH5_Pos)|(SPI2_AF<<GPIO_AFRH_AFRH7_Pos);



	GPIOC->MODER|=GPIO_MODER_MODER2_1;
	GPIOC->MODER&=~(GPIO_MODER_MODER2_0);

	GPIOC->OSPEEDR|=GPIO_OSPEEDR_OSPEEDR2;

	GPIOC->AFR[0]|=(SPI2_AF<<GPIO_AFRL_AFRL2_Pos);

}


void SPI2_Init(void)
{

	RCC->APB1ENR|=RCC_APB1ENR_SPI2EN;

	//software slave management
	SPI2->CR1|=SPI_CR1_SSM|SPI_CR1_SSI;

	/*Set clock to fPCLK/16*/
	SPI2->CR1 |=(SPI_CR1_BR_0|SPI_CR1_BR_1);

	// set SPI as master mode
	SPI2->CR1|=SPI_CR1_MSTR;

	/*Set CPOL to 0 and CPHA to 0*/
	SPI2->CR1 &=~SPI_CR1_CPOL;
	SPI2->CR1 &=~SPI_CR1_CPHA;

	/*Set data size to 8-bit*/
	SPI2->CR2&=~(SPI_CR2_DS_Msk);
	SPI2->CR2|=(0x07<<SPI_CR2_DS_Pos);

	SPI2->CR2|=SPI_CR2_FRXTH;

	SPI2->CR1|=SPI_CR1_SPE;

}

void SPI2_TX(uint8_t *data,uint32_t size)
{



	uint32_t i=0;
	while(i<size)
	{
		/*Wait until TXE is set*/
		while(!(SPI2->SR & (SPI_SR_TXE)))
		{}

		/*Write the data to the data register*/
		*((volatile uint8_t *)&SPI2->DR) = data[i];
		i++;
	}
	/*Wait until TXE is set*/
	while(!(SPI2->SR & (SPI_SR_TXE))){}

	/*Wait for BUSY flag to reset*/
	while((SPI2->SR & (SPI_SR_BSY))){}

	/*Clear OVR flag*/
	(void)SPI2->DR;
	(void)SPI2->SR;

}


void SPI2_RX (uint8_t * data, uint8_t length)
{

	while(length)
	{
		/*Send dummy data*/
		*((volatile uint8_t *)&SPI2->DR) =0xFF;

		/*Wait for RXNE flag to be set*/
		while(!(SPI2->SR & (SPI_SR_RXNE))){}

		/*Read data from data register*/
		*data++ = *((volatile uint8_t *)&SPI2->DR);
		length--;
	}

}

#ifndef TOUCHPINS_H_
#define TOUCHPINS_H_

#include "stdint.h"

void TouchPin_CS_Init(void);
void TouchPin_CS_Low(void);
void TouchPin_CS_High(void);


#endif /* TOUCHPINS_H_ */

#include "TouchPins.h"
#include "stm32f7xx.h"


void TouchPin_CS_Init(void)
{
	RCC->AHB1ENR|=RCC_AHB1ENR_GPIOAEN;

	GPIOA->MODER|=GPIO_MODER_MODER3_0;
	GPIOA->MODER&=~GPIO_MODER_MODER3_1;

	GPIOA->BSRR=GPIO_BSRR_BS3;


}

void TouchPin_CS_Low(void)
{
	GPIOA->BSRR=GPIO_BSRR_BR3;
}

void TouchPin_CS_High(void)
{
	GPIOA->BSRR=GPIO_BSRR_BS3;
}

#ifndef INC_TOUCH_H_
#define INC_TOUCH_H_

#include "stdint.h"


#define TP_PRES_DOWN 0x80
#define TP_CATH_PRES 0x40
#define CMD_RDX 0xD0
#define CMD_RDY 0x90
#define XPT_XMIN 300
#define XPT_YMIN 300
#define XPT_XMAX 3600
#define XPT_YMAX 3400
#define XPT_WIDTH (XPT_XMAX - XPT_XMIN)
#define XPT_HEIGHT (XPT_YMAX - XPT_YMIN)

void XPT2046_Init(void);
void XPT2046_Update(uint16_t *x, uint16_t *y);
uint8_t XPT2046_IsReasonable(uint16_t x, uint16_t y);



#endif /* INC_TOUCH_H_ */

#include "xpt2046.h"
#include "time_base.h"
#include "TouchPins.h"
#include "SPI2.h"




static void XPT2046_SetCS(void)
{
	TouchPin_CS_High();
}

static void XPT2046_ResetCS(void)
{
	TouchPin_CS_Low();
}


/**********************************************************************************************************/

#define T_IRQ XPT2046_ReadIRQ()
#define T_CS_ON XPT2046_SetCS()
#define T_CS_OFF XPT2046_ResetCS()

#define READ_TIMES 	5
#define LOST_VAL 	1
#define ERR_RANGE 50
#define Z_THRESHOLD     400
#define Z_THRESHOLD_INT	75
#define MSEC_THRESHOLD  3

static uint8_t XPT2046_initilazed = 0;


static uint16_t XPT2046_Read_AD(uint8_t CMD)
{
	uint8_t num[2];
	uint16_t ret;

	T_CS_OFF;
	SPI2_TX(&CMD,1);
	delay(6);

	SPI2_RX(num, 2);
	T_CS_ON;

	ret = num[0] << 8 | num[1];
	ret >>= 3;
	ret &= (1<<12)-1;

	return ret;
}

static int16_t besttwoavg( int16_t x , int16_t y , int16_t z ) {
  int16_t da, db, dc;
  int16_t reta = 0;
  if ( x > y ) da = x - y; else da = y - x;
  if ( x > z ) db = x - z; else db = z - x;
  if ( z > y ) dc = z - y; else dc = y - z;

  if ( da <= db && da <= dc ) reta = (x + y) >> 1;
  else if ( db <= da && db <= dc ) reta = (x + z) >> 1;
  else reta = (y + z) >> 1;   //    else if ( dc <= da && dc <= db ) reta = (x + y) >> 1;

  return (reta);
}

void XPT2046_Init(void)
{
	SPI2_Pins_Init();
	SPI2_Init();
	TouchPin_CS_Init();


	XPT2046_initilazed = 1;
}

void XPT2046_Update(uint16_t *x, uint16_t *y)
{
	int16_t data[6];
	static uint32_t ptime = 0;

	if (XPT2046_initilazed == 0) {
		return;
	}

	if (Tick_Get() - ptime < MSEC_THRESHOLD) {
		return;
	}

	int16_t z1 = XPT2046_Read_AD(0xb1); // z1
	int32_t z = z1 + 4095;
	int16_t z2 = XPT2046_Read_AD(0xc1); // z2
	z -= z2;
	if (z >= Z_THRESHOLD) {
		XPT2046_Read_AD(0x91);  // dummy 1st X measure
		data[0] = XPT2046_Read_AD(0x91);
		data[1] = XPT2046_Read_AD(0xd1);
		data[2] = XPT2046_Read_AD(0x91);
		data[3] = XPT2046_Read_AD(0xd1);
	} else {
		data[0] = data[1] = data[2] = data[3] = 0;
	}
	data[4] = XPT2046_Read_AD(0x91);
	data[5] = XPT2046_Read_AD(0xd0);
	ptime = Tick_Get();
	if (z < 0) z = 0;
	int16_t intx = besttwoavg( data[1], data[3], data[5] );
	int16_t inty = besttwoavg( data[0], data[2], data[4] );
	if (z >= Z_THRESHOLD) {
		*x = intx;
		*y = inty;
	}
}

uint8_t XPT2046_IsReasonable(uint16_t x, uint16_t y)
{
	if (x >= XPT_XMIN && x <= XPT_XMAX && y >= XPT_YMIN && y <= XPT_YMAX) {
		return 1;
	}
	return 0;
}

	LCD_Write_Cmd (ILI9341_MAC); // memory access control
	LCD_Write_Data((1<<3)|(1U<<5)|(1<<2));

#define MY_DISP_HOR_RES 320


#define MY_DISP_VER_RES 240

#ifndef INC_TOUCHCONTROLLER_H_
#define INC_TOUCHCONTROLLER_H_

/*********************
 *      INCLUDES
 *********************/
#include "lvgl.h"

/*********************
 *      DEFINES
 *********************/

/**********************
 *      TYPEDEFS
 **********************/

/**********************
 * GLOBAL PROTOTYPES
 **********************/
void lv_port_indev_init(void);

/**********************
 *      MACROS
 **********************/



#endif /* INC_TOUCHCONTROLLER_H_ */

#include "TouchController.h"
#include "lvgl.h"
#include "stdio.h"
#include "xpt2046.h"

#include "ILI_9341.h"
/*********************
 *      DEFINES
 *********************/

/**********************
 *      TYPEDEFS
 **********************/

/**********************
 *  STATIC PROTOTYPES
 **********************/

static void touchpad_init(void);
static void touchpad_read(lv_indev_drv_t * indev_drv, lv_indev_data_t * data);
static bool touchpad_is_pressed(void);
static void touchpad_get_xy(lv_coord_t * x, lv_coord_t * y);


/**********************
 *  STATIC VARIABLES
 **********************/
lv_indev_t * indev_touchpad;


/**********************
 *      MACROS
 **********************/

/**********************
 *   GLOBAL FUNCTIONS
 **********************/

void lv_port_indev_init(void)
{
    /**
     * Here you will find example implementation of input devices supported by LittelvGL:
     *  - Touchpad
     *  - Mouse (with cursor support)
     *  - Keypad (supports GUI usage only with key)
     *  - Encoder (supports GUI usage only with: left, right, push)
     *  - Button (external buttons to press points on the screen)
     *
     *  The `..._read()` function are only examples.
     *  You should shape them according to your hardware
     */

    static lv_indev_drv_t indev_drv;

    /*------------------
     * Touchpad
     * -----------------*/

    /*Initialize your touchpad if you have*/
    touchpad_init();

    /*Register a touchpad input device*/
    lv_indev_drv_init(&indev_drv);
    indev_drv.type = LV_INDEV_TYPE_POINTER;
    indev_drv.read_cb = touchpad_read;
    indev_touchpad = lv_indev_drv_register(&indev_drv);
}

/**********************
 *   STATIC FUNCTIONS
 **********************/


static void ConvXPTtoILI(uint16_t *x, uint16_t *y)
{
	uint16_t tx,ty;
	ty = (int16_t)(((int32_t)*x - XPT_YMIN) * ILI9341_HEIGHT / XPT_HEIGHT);
	ty = (ty < 0) ? 0 : ty;
	ty = (ty >= ILI9341_HEIGHT) ? ILI9341_HEIGHT-1 : ty;

	tx = (int16_t)(((int32_t)*y - XPT_XMIN) * ILI9341_WIDTH / XPT_WIDTH);
	tx = (tx < 0) ? 0 : tx;
	tx = (tx >= ILI9341_WIDTH) ? ILI9341_WIDTH-1 : tx;
	*y = ty;
	*x = ILI9341_WIDTH-tx;
}

struct {
	lv_coord_t x;
	lv_coord_t y;
}get_xy;
/*------------------
 * Touchpad
 * -----------------*/

/*Initialize your touchpad*/
static void touchpad_init(void)
{
    XPT2046_Init();
}

/*Will be called by the library to read the touchpad*/
static void touchpad_read(lv_indev_drv_t * indev_drv, lv_indev_data_t * data)
{
    static lv_coord_t last_x = 0;
    static lv_coord_t last_y = 0;

    /*Save the pressed coordinates and the state*/
    if(touchpad_is_pressed()) {

    	last_x = get_xy.x;
    	last_y = get_xy.y;
        data->state = LV_INDEV_STATE_PR;
    }
    else {
        data->state = LV_INDEV_STATE_REL;
    }

    /*Set the last pressed coordinates*/
    data->point.x = last_x;
    data->point.y = last_y;
}


/*Return true is the touchpad is pressed*/
static bool touchpad_is_pressed(void)
{
	static uint16_t prevx = ILI9341_WIDTH;
	static uint16_t prevy = ILI9341_HEIGHT;
	uint16_t intx, inty;
	XPT2046_Update(&intx, &inty);

	if (XPT2046_IsReasonable(intx, inty))
	{



		ConvXPTtoILI(&intx, &inty);

		if (intx != prevx || inty != prevy)
		{
			prevx = intx;
			prevy = inty;
			get_xy.x = (int32_t)intx;
			get_xy.y = (int32_t)inty;
			return true;
		}
	}
	return 0;
}

/*Get the x and y coordinates if the touchpad is pressed*/
static void touchpad_get_xy(lv_coord_t * x, lv_coord_t * y)
{
    /*Your code comes here*/

    (*x) = 0;
    (*y) = 0;
}

#include "TouchController.h"

lv_port_indev_init();