为何读取电阻触摸屏的例子都是模拟SPI，写了一个硬件SPI发现漂移非常大

abnerle

为何读取电阻触摸屏的例子都是模拟SPI，写了一个硬件SPI发现漂移非常大很不准确难道硬件SPI读取触摸屏有bug？
你们也都是用原子例子的模拟方法吗？我用的4.3寸电阻屏，例子的模拟方法是准确的，硬件SPI就不不准确

abnerle

SPI_InitTypeDef  SPI_InitStructure;

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);
  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_256;
  SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
  SPI_InitStructure.SPI_CRCPolynomial = 7;
  SPI_Init(SPI2, &SPI_InitStructure);
  /* Enable SPI2 */
  SPI_Cmd(SPI2, ENABLE);
SPI速度已经很低了，读取flash是对的，读取触摸屏漂移很大，，

jackwei86

请教下我每次读取 X Y值总读取不到
uint8_t WR_Cmd(uint8_t cmd)
{
        uint8_t Tx_DATA = cmd;
        uint8_t Rx_DATA = 0;
        HAL_StatusTypeDef ndef = HAL_SPI_TransmitReceive(&hspi1,&Tx_DATA,&Rx_DATA,1,500);
        return Rx_DATA;
}
//读取X轴或y轴的ADC值
uint16_t TP_Read_AD(uint8_t cmd)
{
        uint8_t i, j;
        uint16_t NUMH,NUML;
        uint16_t NUM;
        TOUCH_CS_LOW();        /* 打开片选 */
        WR_Cmd(cmd);
        NUMH = WR_Cmd(0xff);
        NUML = WR_Cmd(0xff);
        NUM = (NUMH<<8)+ NUML;
        NUM >>= 4;                //高12位有效
        //printf("NUM[%d] = %d\r\n",i,NUM[i]);
        //TCS=1;
        TOUCH_CS_HIGH();        /*关闭片选 */

  return NUM;
}
值一直都是0xff


SPI 配置:
hspi1.Instance = SPI1;
  hspi1.Init.Mode = SPI_MODE_MASTER;
  hspi1.Init.Direction = SPI_DIRECTION_2LINES;
  hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
  hspi1.Init.CLKPolarity = SPI_POLARITY_HIGH;
  hspi1.Init.CLKPhase = SPI_PHASE_2EDGE;
  hspi1.Init.NSS = SPI_NSS_SOFT;
  hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_16;
  hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
  hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
  hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
  hspi1.Init.CRCPolynomial = 10;