stm32 触摸屏 XPT2046

引脚功能描述 

控制字的控制位命令 

控制字节各位描述 

单端模式输入配置 

差分模式输入配置 

时序 

前8个时钟用来通过DIN引脚输入控制字节，接着的12个时钟周期将完成真正的模数转换，剩下的3个多时钟周期将用来完成被转换器忽略的最后字节（DOUT置低）

举例 

#define TOUCH_READ_TIMES    40 //读取次数

#define TOUCH_ERR_RANGE 20 //误差范围

#define TOUCH_X_CMD 0xD0 //读取X轴

#define TOUCH_Y_CMD 0x90 //读取Y轴

#define TOUCH_Continue_Read 0xFF

#define TOUCH_X_MAX 4000 //X最大值

#define TOUCH_X_MIN 100 //X最小值

#define TOUCH_Y_MAX 4000 //Y最大值

#define TOUCH_Y_MIN 100 //X最小值

#define LCD_CALx_MIN (10) //校准点最小值X

#define LCD_CALx_MAX (tftlcd_data.width - LCD_CALx_MIN) //校准点最大值X

#define LCD_CALy_MIN (10) //校准点最小值Y

#define LCD_CALy_MAX (tftlcd_data.height - LCD_CALy_MIN) //校准点最大值Y

#define LCD_CAL_X   (LCD_CALx_MAX - LCD_CALx_MIN) //方框的宽度

#define LCD_CAL_Y   (LCD_CALy_MAX - LCD_CALy_MIN) //方框的高度

#define TOUCH_CAL_OK        'Y' //校准OK标志

#define TOUCH_CAL_ADDR  200  //校准参数在at24c02的保存地址

typedef struct

{

    u8 flag; 

    short xoffset;

    short yoffset; 

    float xFactor;

    float yFactor;

} calibrate_t;

calibrate_t calibrate = {0};

u16 touchX;

u16 touchY;

void TOUCH_init()

{

    GPIO_InitTypeDef gpioa = 

    {

        GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7,

        GPIO_Speed_50MHz,

        GPIO_Mode_AF_PP

    };

    GPIO_InitTypeDef gpiod6 = 

    {

        GPIO_Pin_6,

        GPIO_Speed_50MHz,

        GPIO_Mode_Out_PP

    };

    GPIO_InitTypeDef gpiod7 = 

    {

        GPIO_Pin_7,

        GPIO_Speed_50MHz,

        GPIO_Mode_IPU

    };

    SPI_InitTypeDef spi = 

    {

        SPI_Direction_2Lines_FullDuplex,

        SPI_Mode_Master, //0x0104

        SPI_DataSize_8b,

        SPI_CPOL_High,

        SPI_CPHA_2Edge,

        SPI_NSS_Soft,

        SPI_BaudRatePrescaler_256,

        SPI_FirstBit_MSB,

        7

    };

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOD, ENABLE);

    GPIO_Init(GPIOA, &gpioa);

    GPIO_Init(GPIOD, &gpiod6);

    GPIO_Init(GPIOD, &gpiod7);

    SPI_Init(SPI1, &spi); //初始化SPI

    SPI_Cmd(SPI1, ENABLE); //使能SPI

}

u16 TOUCH_read(u16 cmd)

{

    u8 i = 0, j = 0;

    u16 tmp;

    u16 value[TOUCH_READ_TIMES] = {0};

    u32 total_value = 0;

    SPI1_SetSpeed(SPI_BaudRatePrescaler_32); //设置SPI速度

    for(i = 0; i < TOUCH_READ_TIMES; i++) //读取次数

    {

        TOUCH_CS = 0;

        SPI1_read_write(cmd);

        value[i] = SPI1_read_write(TOUCH_Continue_Read) << 8; //详见时序

        value[i] |= SPI1_read_write(TOUCH_Continue_Read);

        value[i] >>= 3;

        TOUCH_CS = 1;

    }

    for (i = 0; i < TOUCH_READ_TIMES; i++) //排序

    {

        for (j = i + 1; j < TOUCH_READ_TIMES; j++)

        {

            if (value[i] < value[j])

            {

                tmp = value[i];

                value[i] = value[j];

                value[j] = tmp;

            }

        }

    }

    for (i = 1; i < TOUCH_READ_TIMES - 1; i++) //去掉一个最大值，一个最小值

    {

        total_value += value[i];

    }

    total_value /= (TOUCH_READ_TIMES - 2); //求平均值

    return total_value;

}

u8 TOUCH_readXY(u16 *x, u16 *y)

{

    u16 valueX1, valueY1, valueX2, valueY2;

    valueX1 = TOUCH_read(TOUCH_X_CMD); //读取触摸值

    valueY1 = TOUCH_read(TOUCH_Y_CMD);

    valueX2 = TOUCH_read(TOUCH_X_CMD);

    valueY2 = TOUCH_read(TOUCH_Y_CMD);

    *x = valueX1 > valueX2 ? (valueX1 - valueX2) : (valueX2 - valueX1); 

    *y = valueY1 > valueY2 ? (valueY1 - valueY2) : (valueY2 - valueY1);

    if((*x > TOUCH_ERR_RANGE) || (*y > TOUCH_ERR_RANGE)) //判断容错范围

    {

        return 0xFF;

    }

    *x = (valueX1 + valueX2) / 2;

    *y = (valueY1 + valueY2) / 2;

    if((*x < TOUCH_X_MIN || *x > TOUCH_X_MAX) || //判断边界范围

        (*y < TOUCH_Y_MIN || *y > TOUCH_Y_MAX))

    {

        return 0xFF;

    }

    return 0;

}

void TOUCH_start_calibrate(u16 x, u16 y, u16 *valueX,u16 *valueY) //开始校准

{

    u8 i = 0;

    LCD_Clear(BACK_COLOR); //清屏

    LCD_DrowSign(x, y, BACK_COLOR); //画十字

    while(1)

    {

        if(TOUCH_readXY(valueX, valueY) != 0xFF)

        {

            i++;

            if(i > 10)

            {

                LCD_DrowSign(x, y, BACK_COLOR);

                break;

            }

        }

    }

}

void TOUCH_calibrate()

{

    u16 px[2], py[2], valueX[4], valueY[4];

    float xFactor = 0, yFactor = 0;

    TOUCH_start_calibrate(LCD_CALx_MIN, LCD_CALy_MIN, &valueX[0], &valueY[0]); //第一次校准

    delay_ms(500);

    TOUCH_start_calibrate(LCD_CALx_MIN, LCD_CALy_MAX, &valueX[1], &valueY[1]);

    delay_ms(500);

    TOUCH_start_calibrate(LCD_CALx_MAX, LCD_CALy_MIN, &valueX[2], &valueY[2]);

    delay_ms(500);

    TOUCH_start_calibrate(LCD_CALx_MAX, LCD_CALy_MAX, &valueX[3], &valueY[3]);

    delay_ms(500);

    //整合成对角的两点

    px[0] = (valueX[0] + valueX[1]) / 2;

    py[0] = (valueY[0] + valueY[2]) / 2;

    px[1] = (valueX[3] + valueX[2]) / 2;

    py[1] = (valueY[3] + valueY[1]) / 2;

    //求出比例因子

    xFactor = (float)LCD_CAL_X / (px[1] - px[0]);

    yFactor = (float)LCD_CAL_Y / (py[1] - py[0]); 

    //求出偏移量

    calibrate.xoffset = (short)LCD_CALx_MAX - ((float)px[1] * xFactor);

    calibrate.yoffset = (short)LCD_CALy_MAX - ((float)py[1] * yFactor);

    calibrate.xFactor = xFactor ;

    calibrate.yFactor = yFactor ;

    printf("xoffset %d\n", calibrate.xoffset);

    printf("yoffset %d\n", calibrate.yoffset);

    printf("xFactor %f\n", calibrate.xFactor);

    printf("yFactor %f\n", calibrate.yFactor);

    //保存校准数据到at24c02

    calibrate.flag = TOUCH_CAL_OK;

    at24c02Write_buf((u8*)&calibrate, TOUCH_CAL_ADDR, sizeof(calibrate));   

}

u8 TOUCH_scan() //查看是否触摸

{

    u16 valueX;

    u16 valueY; 

    if(TOUCH_readXY(&valueX, &valueY) == 0xFF)

    {

        return 0xFF;

    }

    //根据物理坐标，计算彩屏坐标

    touchX = valueX * calibrate.xFactor + calibrate.xoffset;

    touchY = valueY * calibrate.yFactor + calibrate.yoffset;

    if((touchX > tftlcd_data.width) || (touchY > tftlcd_data.height))

    {

        return 0xFF;

    }

    return 0;

}

int main(void)

{

    I2C_init();

    TOUCH_init();

    at24c02Read_buf((u8*)&calibrate, TOUCH_CAL_ADDR, sizeof(calibrate));

    if(calibrate.flag != TOUCH_CAL_OK) //判断是否已经校准

    {

        TOUCH_calibrate();

    }

    LCD_ShowString(tftlcd_data.width-40,0,tftlcd_data.width,tftlcd_data.height,16,"clear");

    while(1)

    {

        if(TOUCH_scan() == 0)

        {

            LCD_Fill(touchX-1, touchY-1, touchX+2, touchY+2, FRONT_COLOR); //画粗线

            if((touchX > tftlcd_data.width-40) && (touchY < 20))

            {

                LCD_Fill(0, 0, tftlcd_data.width,tftlcd_data.height, BACK_COLOR); //清屏

                LCD_ShowString(tftlcd_data.width-40,0,tftlcd_data.width,tftlcd_data.height,16,"clear");

            }

        }

    }

}