XPT2046驱动代码

以下是XPT2046触摸屏控制器的驱动代码示例，供参考：

#include "stm32f10x.h"
#include "stm32f10x_spi.h"
#include "xpt2046.h"

#define XPT2046_CS_LOW()    GPIO_ResetBits(GPIOB, GPIO_Pin_12)
#define XPT2046_CS_HIGH()   GPIO_SetBits(GPIOB, GPIO_Pin_12)

static void XPT2046_SPI_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    SPI_InitTypeDef SPI_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_SPI2, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_15;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
    SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
    SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
    SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
    SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
    SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_2;
    SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_InitStructure.SPI_CRCPolynomial = 7;
    SPI_Init(SPI2, &SPI_InitStructure);

    SPI_Cmd(SPI2, ENABLE);
}

static uint8_t XPT2046_SPI_ReadWrite(uint8_t data)
{
    while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);
    SPI_I2S_SendData(SPI2, data);
    while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == RESET);
    return SPI_I2S_ReceiveData(SPI2);
}

void XPT2046_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    XPT2046_CS_HIGH();
    XPT2046_SPI_Init();
}

int16_t XPT2046_GetData(uint8_t addr)
{
    uint8_t tx_data[3], rx_data[3];
    uint16_t data = 0;

    XPT2046_CS_LOW();
    tx_data[0] = addr;
    tx_data[1] = 0x00;
    tx_data[2] = 0x00;
    XPT2046_SPI_ReadWrite(tx_data[0]);  // Start bit
    rx_data[0] = XPT2046_SPI_ReadWrite(tx_data[1]);  // High byte
    rx_data[1] = XPT2046_SPI_ReadWrite(tx_data[2]);  // Low byte
    XPT2046_CS_HIGH();

    data = ((rx_data[0] << 5) | (rx_data[1] >> 3)) & 0xFFF;

    return data;
}

void XPT2046_GetCoordinates(uint16_t *x, uint16_t *y)
{
    *x = XPT2046_GetData(0xD0);
    *y = XPT2046_GetData(0x90);
}

使用时可调用`XPT2046_Init()`进行初始化，然后调用`XPT2046_GetCoordinates()`获取坐标数据。其中，`XPT2046_GetData()`函数用于读取指定地址的16位数据。