写一个STM32 SPI的demo程序

好的，下面是一个STM32 SPI的demo程序：

#include "stm32f10x.h"
#include "stm32f10x_spi.h"
#include "stm32f10x_gpio.h"
#include "stm32f10x_rcc.h"

void SPI_Configuration(void)
{
  SPI_InitTypeDef SPI_InitStructure;
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_SPI1, ENABLE);

  /* Configure SPI pins: SCK, MISO and MOSI ---------------------------------*/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Configure GPIO PIN for Chip select */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* SPI 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;
  SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
  SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
  SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;
  SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
  SPI_InitStructure.SPI_CRCPolynomial = 7;
  SPI_Init(SPI1, &SPI_InitStructure);

  /* Enable SPI1 */
  SPI_Cmd(SPI1, ENABLE);
}

void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOC, &GPIO_InitStructure);
}

void delay_ms(uint32_t ms)
{
  volatile uint32_t nCount;
  RCC_ClocksTypeDef RCC_Clocks;
  RCC_GetClocksFreq(&RCC_Clocks);
  nCount = (RCC_Clocks.HCLK_Frequency / 10000) * ms;
  for (; nCount != 0; nCount--);
}

int main(void)
{
  uint8_t data_tx, data_rx;

  GPIO_Configuration();
  SPI_Configuration();

  while (1)
  {
    GPIO_SetBits(GPIOA, GPIO_Pin_4); // Set CS high
    delay_ms(1000);
    GPIO_ResetBits(GPIOA, GPIO_Pin_4); // Set CS low

    data_tx = 0x55; // Send data 0x55
    SPI_I2S_SendData(SPI1, data_tx);
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
    while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_BSY) == SET);
    data_rx = SPI_I2S_ReceiveData(SPI1);

    GPIO_SetBits(GPIOC, GPIO_Pin_13); // LED on
    delay_ms(500);
    GPIO_ResetBits(GPIOC, GPIO_Pin_13); // LED off
    delay_ms(500);
  }
}

此示例程序使用了STM32的SPI1模块和GPIO，其中PA5、PA6、PA7分别连接到SPI的SCK、MISO和MOSI引脚，PA4用于片选控制，PC13用于控制LED灯。程序中的主函数循环中通过SPI发送0x55，然后通过SPI接收到的数据控制LED灯闪烁。具体实现过程中，需要根据实际硬件连接情况进行相应修改。