main.c

stm32初级例程

/**************************************************************
**  精英STM32开发板
**  版本：V1.0
**  功能：	不断查询串口状态，看串口是否收到数据
			串口1配置如下
			 115200,8,N,1
			本串口程序是接收到什么字符就返回什么字符
			使用我提供的串口调试工具，选择【串口超级终端】波特率设置115200
***************************************************************/

/* Includes ------------------------------------------------------------------*/
#define SYS_GLOBALS
#include "include.h"


/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void NVIC_Configuration(void);
void GPIO_Configuration(void);
void USART1_InitConfig(uint32 BaudRate);
/* Private functions ---------------------------------------------------------*/

//考虑到效率问题，串口初始化用库函数
//串口收发函数仍然直接操作寄存器
/*----------------------------------------------------------------------------
  从串口发送一个字节数据
  Write character to Serial Port.
 *----------------------------------------------------------------------------*/
int SendChar (int ch)  {

  //等待发送结束
  while (!(USART1->SR & USART_FLAG_TXE));
  //将数据放入发送寄存器
  USART1->DR = (ch & 0x1FF);

  return (ch);
}

/*----------------------------------------------------------------------------
  从串口读取一个字节数据，直到读到数据才返回
  Read character to Serial Port.
 *----------------------------------------------------------------------------*/
int GetKey (void)  {

  //等待接收结束
  while (!(USART1->SR & USART_FLAG_RXNE));
  //从接受寄存器读取数据并返回
  return ((int)(USART1->DR & 0x1FF));
}

/*******************************************************************************
* Function Name  : main
* Description    : Main program.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
int main(void)
{
#ifdef DEBUG
  debug();
#endif

  /* System Clocks Configuration */
  RCC_Configuration();//配置系统时钟   

  GPIO_Configuration();//配置GPIO
  

  /* NVIC configuration */
  NVIC_Configuration();//配置中断

  //配置串口
  USART1_InitConfig(115200);

  //串口实验开始
  printf ("Polling mode Serial I/O Example\r\n\r\n");

  while (1)
  {                                     // Loop forever
    unsigned char c;
    //提示从串口输入1个字符
    printf ("Press a key. ");
    //从串口接收1个字符
    c = getchar ();
    //从串口输出回车换行
    printf ("\r\n");
    //从串口输出接收到的字符
    printf ("You pressed '%c'.\r\n\r\n", c);
  } // end while
  
}

//串口初始化函数
void USART1_InitConfig(uint32 BaudRate)
{USART_InitTypeDef USART_InitStructure;
 GPIO_InitTypeDef GPIO_InitStructure; 
  
  //使能串口的RCC时钟
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);
  
  //串口使用的GPIO口配置
  //配置串口接收脚
  /* Configure USART1 Rx (PA.10) as input floating */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  
  /* Configure USART1 Tx (PA.09) as alternate function push-pull */
  //配置串口发送脚
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  //配置串口
  USART_InitStructure.USART_BaudRate = BaudRate;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

  /* Configure USART1 */
  USART_Init(USART1, &USART_InitStructure);//配置串口1

  /* Enable the USART1 */
  USART_Cmd(USART1, ENABLE);//使能串口1
}
/*******************************************************************************
* Function Name  : RCC_Configuration
* Description    : Configures the different system clocks.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void RCC_Configuration(void)
{ErrorStatus HSEStartUpStatus;   
  
  /* RCC system reset(for debug purpose) */
  RCC_DeInit();

  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);//使能外部时钟 

  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();//等待外部时钟就绪

  if(HSEStartUpStatus == SUCCESS)
  {
    /* Enable Prefetch Buffer 启用预取缓冲器 */
    FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

    /* Flash 2 wait state FLASH设置2个等待周期*/
    FLASH_SetLatency(FLASH_Latency_2);
 
    /* HCLK = SYSCLK 设置系统设置*/
    RCC_HCLKConfig(RCC_SYSCLK_Div1); 
  
    /* PCLK2 = HCLK PCLK2时钟=主时钟*/
    RCC_PCLK2Config(RCC_HCLK_Div1); 

    /* PCLK1 = HCLK/2 PCLK1时钟为主时钟1/2*/
    RCC_PCLK1Config(RCC_HCLK_Div2);

    /* PLLCLK = 8MHz * 9 = 72 MHz 设置时钟为72M*/
    RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

    /* Enable PLL 使能PLL*/ 
    RCC_PLLCmd(ENABLE);

    /* Wait till PLL is ready 等待PLL工作稳定*/
    while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
    {
    }

    /* Select PLL as system clock source 选择PLL做为系统时钟源*/
    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

    /* Wait till PLL is used as system clock source 准备就绪，开始干活*/
    while(RCC_GetSYSCLKSource() != 0x08)
    {
    }
  }
}

/*******************************************************************************
* Function Name  : GPIO_Configuration
* Description    : Configures the different GPIO ports.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  
  /* Enable GPIO_LED clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);//使能GPIO时钟
  //LED_init-------------------------------------------------------

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(GPIOC, &GPIO_InitStructure);			 //设置GPIO为输出
  
}

/*******************************************************************************
* Function Name  : NVIC_Configuration
* Description    : Configures Vector Table base location.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void NVIC_Configuration(void)
{

//#ifdef  VECT_TAB_RAM
#if defined (VECT_TAB_RAM)
  /* Set the Vector Table base location at 0x20000000 */ 
  NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0); //设置中断向量在RAM中
//#elif defined(VECT_TAB_FLASH_IAP)
//  NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x2000);
#else  /* VECT_TAB_FLASH  */
  /* Set the Vector Table base location at 0x08000000 */ 
  NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0); //设置中断向量在FLASH中  
#endif


}




#ifdef  DEBUG
/*******************************************************************************
* Function Name  : assert_failed
* Description    : Reports the name of the source file and the source line number
*                  where the assert_param error has occurred.
* Input          : - file: pointer to the source file name
*                  - line: assert_param error line source number
* Output         : None
* Return         : None
*******************************************************************************/
void assert_failed(u8* file, u32 line)
{ 
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
}
#endif

/******************* (C) COPYRIGHT 2008 STMicroelectronics *****END OF FILE****/