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");            }        }    }}