main.c

stm32初级例程

/**************************************************************
**  精英STM32开发板
**  版本：V1.0
**  功能：LED循环闪烁
***************************************************************/


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

#define u16  unsigned short
#define u32  unsigned long

u32 volatile gTimer_1ms=0;



/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void NVIC_Configuration(void);
void GPIO_Configuration(void);

/*------------------------------------------------------------------------------
  Systick 中断函数
  SysTick 1 ms中断1次
 *------------------------------------------------------------------------------*/
void SysTickHandler(void) 
{
    gTimer_1ms++;
} // end SysTick_Handler

void SysTick_Init(void)
{
  
  /* SysTick end of count event each 1ms with input clock equal to 9MHz (HCLK/8, default) */
  //设置系统定时器中断时间为1ms
  SysTick_SetReload(9000);
  /* Enable SysTick interrupt */
  //允许系统定时器中断
  SysTick_ITConfig(ENABLE);
  /* Enable the SysTick Counter */
  //使能系统定时器
  SysTick_CounterCmd(SysTick_Counter_Enable);
}

//LED循环闪烁
void LedFlash(void)
{
  static u16 leds = 0x01;
  u16 temp;
    
    //先读出PC端口状态
    temp = GPIO_ReadInputData(GPIOC);
    
    //先屏蔽掉PC0~PC2
    temp |= 0x0007;
    
    //重新设置PC0~PC2输出状态，IO输出低电平点亮LED
    temp &= (~(leds));
    GPIO_Write(GPIOC, temp);
    leds <<= 1;
    if ( (leds&0x0f) == 0)
	     leds = 0x01;
}

//精确的延时
void Delay(u32 nTime)
{u32 counter;
  
  counter=gTimer_1ms;
  while( gTimer_1ms-counter < nTime);//定时时间到才退出
  
}

/* Private functions ---------------------------------------------------------*/

/*******************************************************************************
* 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
  
  SysTick_Init();//系统定时器初始化
  
  //关闭所有LED
  GPIO_Write(GPIOC, GPIO_ReadInputData(GPIOC)|0x0000007);
  
  Delay(20);  
  
  while (1)
  {
     Delay(50);
	   
	   //循环显示1位LED
	   LedFlash();
	   
	   Delay(50);
	   
	   //关闭所有LED
	   GPIO_Write(GPIOC, GPIO_ReadInputData(GPIOC)|0x00000007);
  }
}


/*******************************************************************************
* 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-------------------------------------------------------
  ////配置管脚
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;//最大输出速度为50MHz
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;////通用推挽输出
  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****/