STM32 SPI CRC 出错求解

2013-2-20 13:53

使用SPI的CRC校验的时候每次都是发现同样的数据 0XAA 但是后面发生的SPI CRC校验值都是不一样的，这是什么原因  求指点求讨论。

int main(void)
{
  unsigned char temp_data,p[3];
  SystemInit();
  RCC_Configuration();

  SPI2_Init();

  LED_GPIO_Config();
  LED1(OFF);

  while (1)
  {
      SPI2_CS_LOW();

      while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);

      SPI_I2S_SendData(SPI2, 0xAA);
      SPI_TransmitCRC(SPI2);
      while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == RESET);
      p[0]= SPI_I2S_ReceiveData(SPI2);
      while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == RESET);
      if ((SPI_I2S_GetFlagStatus(SPI2, SPI_FLAG_CRCERR)) == SET)
      {
            p[2]=1;
      }
      else       p[2]=0;
      p[1] = SPI_I2S_ReceiveData(SPI2);
      SPI2_CS_HIGH();
      Delay(0xff);
  }
}

void SPI2_Init(void)
{
  SPI_InitTypeDef  SPI_InitStructure;
  GPIO_InitTypeDef GPIO_InitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB , ENABLE);

  /*!< SPI_FLASH_SPI Periph clock enable */

  /*!< AFIO Periph clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);

  /*!< Configure SPI_FLASH_SPI pins: SCK */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  /*!< Configure SPI_FLASH_SPI pins: MISO */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  /*!< Configure SPI_FLASH_SPI pins: MOSI */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  /*!< Configure SPI_FLASH_SPI_CS_PIN pin: SPI_FLASH Card CS pin */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  /* Deselect the FLASH: Chip Select high */
  //SPI2_CS_HIGH();

  /* SPI2 configuration */
  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;       //CPOL=0 时钟悬空低
  //SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
  //SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;          //CPHA=0 数据捕获第1个
  SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
  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_CR1|=(1<<13);

  SPI_Init(SPI2, &SPI_InitStructure);
// SPI_CalculateCRC(SPI1,ENABLE);
  SPI_CalculateCRC(SPI2,ENABLE);
  /* Enable SPI2  */
  SPI_Cmd(SPI2, ENABLE);

}

2013-2-20 13:53

2013-2-20 13:55

连着多个数据数据都是0xaa 后面的校验码没一个相同的一会一个样纳闷啊使用STM8S 写类似的程序，情况是一样的

2013-2-21 09:22

这么快就沉了啊

2013-2-22 00:02

真的沉了

2013-2-25 21:56

SPI2 时钟发生 0XAA 后面跟CRC校验值生成多项式也没有变啊 CRC校验值怎么老变呢求高手指点一下。先谢谢了

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STM32 SPI CRC 出错求解

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