STM32F030C8T6的SPI配置不成功？

zenmvol · 发表于 2017-6-21 21:47:30

SPI配置完成后，在使用发送函数时
unsigned char SPI2_SendByte(unsigned char byte)
{
while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);/* Loop while DR register in not emplty */

SPI_SendData8(SPI2, byte);/* Send byte through the SPI1 peripheral */

while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == RESET);/* Wait to receive a byte */

return SPI_ReceiveData8(SPI2);/* Return the byte read from the SPI bus */
}

一直死在这个while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);是不是表示SPI没有配置成功？或是系统时钟配置不对导致的？
下面是时钟的配置
uint32_t SystemCoreClock = 8000000;
__I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};

/**
  * @}
  */

/** @addtogroup STM32F0xx_System_Private_FunctionPrototypes
  * @{
  */

static void SetSysClock(void);

/**
  * @}
  */

/** @addtogroup STM32F0xx_System_Private_Functions
  * @{
  */

/**
  * @brief  Setup the microcontroller system.
  *       Initialize the Embedded Flash Interface, the PLL and update the
  *       SystemCoreClock variable.
  * @param  None
  * @retval None
  */
void SystemInit (void)
{
  /* Set HSION bit */
  RCC->CR |= (uint32_t)0x00000001;

  /* Reset SW[1:0], HPRE[3:0], PPRE[2:0], ADCPRE and MCOSEL[2:0] bits */
  RCC->CFGR &= (uint32_t)0xF8FFB80C;

  /* Reset HSEON, CSSON and PLLON bits */
  RCC->CR &= (uint32_t)0xFEF6FFFF;

  /* Reset HSEBYP bit */
  RCC->CR &= (uint32_t)0xFFFBFFFF;

  /* Reset PLLSRC, PLLXTPRE and PLLMUL[3:0] bits */
  RCC->CFGR &= (uint32_t)0xFFC0FFFF;

  /* Reset PREDIV1[3:0] bits */
  RCC->CFGR2 &= (uint32_t)0xFFFFFFF0;

  /* Reset USARTSW[1:0], I2CSW, CECSW and ADCSW bits */
  RCC->CFGR3 &= (uint32_t)0xFFFFFEAC;

  /* Reset HSI14 bit */
  RCC->CR2 &= (uint32_t)0xFFFFFFFE;

  /* Disable all interrupts */
  RCC->CIR = 0x00000000;

  /* Configure the System clock frequency, AHB/APBx prescalers and Flash settings */
  SetSysClock();
}

/**
  * @brief  Update SystemCoreClock according to Clock Register Values
  *       The SystemCoreClock variable contains the core clock (HCLK), it can
  *       be used by the user application to setup the SysTick timer or configure
  *       other parameters.
  *
  * @note Each time the core clock (HCLK) changes, this function must be called
  *       to update SystemCoreClock variable value. Otherwise, any configuration
  *       based on this variable will be incorrect.
  *
  * @note - The system frequency computed by this function is not the real
  *          frequency in the chip. It is calculated based on the predefined
  *          constant and the selected clock source:
  *
  *          - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(*)
  *
  *          - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**)
  *
  *          - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**)
  *          or HSI_VALUE(*) multiplied/divided by the PLL factors.
  *
  *       (*) HSI_VALUE is a constant defined in stm32f0xx.h file (default value
  *          8 MHz) but the real value may vary depending on the variations
  *          in voltage and temperature.
  *
  *       (**) HSE_VALUE is a constant defined in stm32f0xx.h file (default value
  *             8 MHz), user has to ensure that HSE_VALUE is same as the real
  *             frequency of the crystal used. Otherwise, this function may
  *             have wrong result.
  *
  *       - The result of this function could be not correct when using fractional
  *          value for HSE crystal.
  * @param  None
  * @retval None
  */
void SystemCoreClockUpdate (void)
{
  uint32_t tmp = 0, pllmull = 0, pllsource = 0, prediv1factor = 0;

  /* Get SYSCLK source -------------------------------------------------------*/
  tmp = RCC->CFGR & RCC_CFGR_SWS;

  switch (tmp)
  {
case 0x00:  /* HSI used as system clock */
   SystemCoreClock = HSI_VALUE;
   break;
case 0x04:  /* HSE used as system clock */
   SystemCoreClock = HSE_VALUE;
   break;
case 0x08:  /* PLL used as system clock */
   /* Get PLL clock source and multiplication factor ----------------------*/
   pllmull = RCC->CFGR & RCC_CFGR_PLLMULL;
   pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;
   pllmull = ( pllmull >> 18) + 2;

   if (pllsource == 0x00)
   {
      /* HSI oscillator clock divided by 2 selected as PLL clock entry */
      SystemCoreClock = (HSI_VALUE >> 1) * pllmull;
   }
   else
   {
      prediv1factor = (RCC->CFGR2 & RCC_CFGR2_PREDIV1) + 1;
      /* HSE oscillator clock selected as PREDIV1 clock entry */
      SystemCoreClock = (HSE_VALUE / prediv1factor) * pllmull;
   }
   break;
default: /* HSI used as system clock */
   SystemCoreClock = HSI_VALUE;
   break;
  }
  /* Compute HCLK clock frequency ----------------*/
  /* Get HCLK prescaler */
  tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)];
  /* HCLK clock frequency */
  SystemCoreClock >>= tmp;
}

/**
  * @brief  Configures the System clock frequency, AHB/APBx prescalers and Flash
  *       settings.
  * @note This function should be called only once the RCC clock configuration
  *       is reset to the default reset state (done in SystemInit() function).
  * @param  None
  * @retval None
  */
static void SetSysClock(void)
{
  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;

/******************************************************************************/
/*          PLL (clocked by HSE) used as System clock source             */
/******************************************************************************/

  /* SYSCLK, HCLK, PCLK configuration ----------------------------------------*/
  /* Enable HSE */
  RCC->CR |= ((uint32_t)RCC_CR_HSEON);

  /* Wait till HSE is ready and if Time out is reached exit */
  do
  {
HSEStatus = RCC->CR & RCC_CR_HSERDY;
StartUpCounter++;
  } while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));

  if ((RCC->CR & RCC_CR_HSERDY) != RESET)
  {
HSEStatus = (uint32_t)0x01;
  }
  else
  {
HSEStatus = (uint32_t)0x00;
  }

  if (HSEStatus == (uint32_t)0x01)
  {
/* Enable Prefetch Buffer and set Flash Latency */
FLASH->ACR = FLASH_ACR_PRFTBE | FLASH_ACR_LATENCY;

   /* HCLK = SYSCLK / 1 */
   RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;

   /* PCLK = HCLK / 2 */
   RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE_DIV2;

/* PLL configuration */
RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_PREDIV1 | RCC_CFGR_PLLMULL2);
RCC->CFGR2 &= (uint32_t)((uint32_t)~(RCC_CFGR2_PREDIV1));
RCC->CFGR2 |= (uint32_t)(RCC_CFGR2_PREDIV1_DIV6);

/* Enable PLL */
RCC->CR |= RCC_CR_PLLON;

/* Wait till PLL is ready */
while((RCC->CR & RCC_CR_PLLRDY) == 0)
{
}

/* Select PLL as system clock source */
RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;

/* Wait till PLL is used as system clock source */
while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_PLL)
{
}
  }
  else
  { /* If HSE fails to start-up, the application will have wrong clock
      configuration. User can add here some code to deal with this error */
  }
}

这是SPI的配置
void spi2_Init(void)
{
GPIO_InitTypeDef  GPIO_InitStructure;
SPI_InitTypeDef  SPI_InitStructure;

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);//使能GPIOB时钟
RCC_APB1PeriphResetCmd(RCC_APB1Periph_SPI2, ENABLE);//使能SPI2时钟

GPIO_PinAFConfig(GPIOB,GPIO_PinSource13,GPIO_AF_0);
GPIO_PinAFConfig(GPIOB,GPIO_PinSource14,GPIO_AF_0);
GPIO_PinAFConfig(GPIOB,GPIO_PinSource15,GPIO_AF_0);

//GPIO初始化设置
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13|GPIO_Pin_14|GPIO_Pin_15;//PB13~15复用功能输出
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//复用功能
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;//推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;//50MHz
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;//
GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化

//这里只针对SPI口初始化
SPI_I2S_DeInit(SPI2);

SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;  //设置SPI单向或者双向的数据模式:SPI设置为双线双向全双工
SPI_InitStructure.SPI_Mode = SPI_Mode_Master; //设置SPI工作模式:设置为主SPI
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b; //设置SPI的数据大小:SPI发送接收8位帧结构
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low; //串行同步时钟的空闲状态为低电平
SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge; //串行同步时钟的第一个跳变沿（上升或下降）数据被采样
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft; //NSS信号由硬件（NSS管脚）还是软件（使用SSI位）管理:内部NSS信号有SSI位控制
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8; //定义波特率预分频的值:波特率预分频值为2
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; //指定数据传输从MSB位还是LSB位开始:数据传输从MSB位开始
SPI_InitStructure.SPI_CRCPolynomial = 7; //CRC值计算的多项式
SPI_Init(SPI2, &SPI_InitStructure);  //根据SPI_InitStruct中指定的参数初始化外设SPIx寄存器

SPI_Cmd(SPI2, ENABLE); //使能SPI外设

}