072RB-Nucleo上手之SPI

[复制链接]

woshilee 发布时间：2014-12-16 19:36

技术帖
文章封面:	-
文章简介:	-

本帖最后由 woshilee 于 2014-12-16 19:55 编辑

M0的SPI终于调通了，玩儿M3,M4多了现在玩M0就有了固定的思维模式，老路走不通的话就要找它们之间的不同之处了贴上程序吧
#include "stm32f0xx.h"
#include "stdio.h"
uint8_t       getbyte=0;
/**
  * @brief  Delay
  * @param  None
  * @retval None
  */
void delay1ms(unsigned int ms)
{
unsigned int i,j;
for(i=0; i<ms; i++)
      for(j=0; j<100; j++);
}

/**
  * @brief  GPIO Config
  * @param  None
  * @retval None
  */
void GPIO_Configuration(void)
{
GPIO_InitTypeDef       GPIO_InitStructure;

/* Configure  PA5£¬PA7 in output nopull mode */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_7;
      GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
      GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;
GPIO_Init(GPIOA, &GPIO_InitStructure);


GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
// GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;//ÍÆÍì¸´ÓÃÊä³ö
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;//Ðü¿Õ»òÉÏÀÊäÈë
GPIO_Init(GPIOA, &GPIO_InitStructure);

GPIO_PinAFConfig(GPIOA,GPIO_PinSource4, GPIO_AF_0);
GPIO_PinAFConfig(GPIOA,GPIO_PinSource5, GPIO_AF_0);
GPIO_PinAFConfig(GPIOA,GPIO_PinSource6, GPIO_AF_0);
GPIO_PinAFConfig(GPIOA,GPIO_PinSource7, GPIO_AF_0);
}
void RCC_Configuration(void)
{
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
}
void SPI_Configuration(void)
{
SPI_InitTypeDef SPI_InitStructure;
            SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
            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_InitStructure.SPI_Mode = SPI_Mode_Master;
            SPI_Init(SPI1, &SPI_InitStructure);
            SPI_NSSInternalSoftwareConfig(SPI1, SPI_NSSInternalSoft_Set);

            SPI_RxFIFOThresholdConfig(SPI1, SPI_RxFIFOThreshold_QF);

            SPI_Cmd(SPI1, ENABLE); /* SPI enable */

}

uint8_t SPI1_ReadWriteByte(uint8_t TxData)
{
      uint8_t RxData = 0;
      while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);       //µÈ´ý·¢ËÍ»º³åÇø¿Õ
      SPI_SendData8(SPI1, TxData);                                        //·¢Ò»¸ö×Ö½Ú

  while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
      RxData = SPI_ReceiveData8(SPI1);//SPI2                                  //·µ»Ø½ÓÊÕµ½µÄÊý¾Ý*/
      return (uint8_t)RxData;
}

int main(void)
{

      RCC_Configuration();
      GPIO_Configuration();
      SPI_Configuration();

// NVIC_Configuration();


      while (1)
      {

      getbyte=SPI1_ReadWriteByte(0x55);
            delay1ms(100);
}
}
红色的语句在M3中是没有的，在M0中这个函数的定义如下：

/**
  * @brief  Configures the FIFO reception threshold for the selected SPI.
  * @param  SPIx: where x can be 1 or 2 to select the SPI peripheral.
  * @param  SPI_RxFIFOThreshold: specifies the FIFO reception threshold.
  * This parameter can be one of the following values:
  *    @arg SPI_RxFIFOThreshold_HF: RXNE event is generated if the FIFO
  *       level is greater or equal to 1/2.
  *    @arg SPI_RxFIFOThreshold_QF: RXNE event is generated if the FIFO
  *       level is greater or equal to 1/4.
  * @retval None
  */
void SPI_RxFIFOThresholdConfig(SPI_TypeDef* SPIx, uint16_t SPI_RxFIFOThreshold)
{
  /* Check the parameters */
  assert_param(IS_SPI_ALL_PERIPH(SPIx));
  assert_param(IS_SPI_RX_FIFO_THRESHOLD(SPI_RxFIFOThreshold));

  /* Clear FRXTH bit */
  SPIx->CR2 &= (uint16_t)~((uint16_t)SPI_CR2_FRXTH);

  /* Set new FRXTH bit value */
  SPIx->CR2 |= SPI_RxFIFOThreshold;
}

如果不加这句话的话，肯定会卡在判断RXNE位的地方，因为没有产生这个标志，如果用延时的代替的话是可以发送出去的，但是时序就会有问题，因为发送语句执行后不是立即就完成的。希望大家注意到这一点

所有SPI 数据换都通过32 位的嵌入式FIFO，设置FRXTH 位。 RXFIFO 的阈值必须和对SPIx_DR 寄存器的读访问的字长对齐比如发送的是8位的数据，就要设置SPI_RxFIFOThreshold_QF: RXNE event is generated if the FIFO   *level is greater or equal to 1/4. 就是32/4=8--》1个字节
如果发送的是16位数据就要设置SPI_RxFIFOThreshold_HF: RXNE event is generated if the FIFO   *level is greater or equal to 1/2.就是 32/2=16--》2个字节