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);
}
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