关于STM32F1的SPI通信问题

AuroraWU · 发表于 2019-9-24 17:14:11

利用SPI与ws1850通信，基础配置如下：系统时钟72M
oid SPI1_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  SPI_InitTypeDef  SPI_InitStructure;
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOB, ENABLE );//PORTBÊ±ÖÓÊ¹ÄÜ
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOA, ENABLE );//PORTBÊ±ÖÓÊ¹ÄÜ
RCC_APB2PeriphClockCmd( RCC_APB2Periph_SPI1,  ENABLE );//SPI1Ê±ÖÓÊ¹ÄÜ

  /*!< Configure pins: SCK */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  /*!< Configure pins: MISO */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  /*!< Configure pins: MOSI */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  /*!< Configure pins: CS */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;  //ÉèÖÃSPIµ¥Ïò»òÕßË«ÏòµÄÊý¾ÝÄ£Ê½:SPIÉèÖÃÎªË«ÏßË«ÏòÈ«Ë«¹¤
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;  //ÉèÖÃSPI¹¤×÷Ä£Ê½:ÉèÖÃÎªÖ÷SPI
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;  //ÉèÖÃSPIµÄÊý¾Ý´óÐ¡:SPI·¢ËÍ½ÓÊÕ8Î»Ö¡½á¹¹
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;  //´®ÐÐÍ¬²½Ê±ÖÓµÄ¿ÕÏÐ×´Ì¬Îª¸ßµçÆ½
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge; //´®ÐÐÍ¬²½Ê±ÖÓµÄµÚ¶þ¸öÌø±äÑØ£¨ÉÏÉý»òÏÂ½µ£©Êý¾Ý±»²ÉÑù
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;  //NSSÐÅºÅÓÉÓ²¼þ£¨NSS¹Ü½Å£©»¹ÊÇÈí¼þ£¨Ê¹ÓÃSSIÎ»£©¹ÜÀí:ÄÚ²¿NSSÐÅºÅÓÐSSIÎ»¿ØÖÆ
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;  //¶¨Òå²¨ÌØÂÊÔ¤·ÖÆµµÄÖµ:²¨ÌØÂÊÔ¤·ÖÆµÖµÎª256
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; //Ö¸¶¨Êý¾Ý´«Êä´ÓMSBÎ»»¹ÊÇLSBÎ»¿ªÊ¼:Êý¾Ý´«Êä´ÓMSBÎ»¿ªÊ¼
SPI_InitStructure.SPI_CRCPolynomial = 7; //CRCÖµ¼ÆËãµÄ¶àÏîÊ½
SPI_Init(SPI1, &SPI_InitStructure);  //¸ù¾ÝSPI_InitStructÖÐÖ¸¶¨µÄ²ÎÊý³õÊ¼»¯ÍâÉèSPIx¼Ä´æÆ÷

SPI_Cmd(SPI1, ENABLE); //Ê¹ÄÜSPIÍâÉè
//SPI2_ReadWriteByte(0xff);//Æô¶¯´«Êä

SPI1_SetSpeed(SPI_BaudRatePrescaler_256);

// GPIO_ResetBits(PINB,CS);
// delay_us(10);
// GPIO_SetBits(PINB,CS);
// delay_us(10);

}
！！问题在于，读取SPI数据的时候，我得先读取两次空值（0），第三次读取才是正确的值，这是为什么？！！
读取函数如下：

unsigned char ReadRawRC(unsigned char Address)
{
  unsigned char ucAddr;
  unsigned char ucResult=0,h,l;
  GPIO_ResetBits(PINB,CS);
  ucAddr = ((Address<<1)&0x7E)|0x80;

  SPI_I2S_SendData(SPI1,ucAddr);
while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI1, 0xff);
h=SPI_I2S_ReceiveData(SPI1);
while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
l=SPI_I2S_ReceiveData(SPI1);//红色部分不可删去，否则数据读取出错，至于怎么确定是对的数值，我先往该寄存器写入，然后再读取。

while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
ucResult=SPI_I2S_ReceiveData(SPI1);
  GPIO_SetBits(PINB,CS);
  return ucResult;
}
顺便附上写入函数：
void WriteRawRC(unsigned char Address, unsigned char value)
{
  unsigned char ucAddr;
GPIO_ResetBits(PINB,CS);
  ucAddr = ((Address<<1)&0x7E);
SPI_I2S_SendData(SPI1,ucAddr);
while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);

  SPI_I2S_SendData(SPI1, value);
  while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_BSY) == SET);
  GPIO_SetBits(PINB,CS);
}

AuroraWU · 发表于 2019-9-24 17:17:49

之前和2.4G模块通信，也是同样问题，要先读取两次没有关联的值，然后第三次才是对的。

翼行园子 · 发表于 2019-9-24 21:50:41

你试下用原子的驱动代码看看有这个情况吗

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