main.c

stm32初级例程

/*----------------------------------------------------------------------------
例子使用TIM4,的通道3，通道4产生2个固定占空比的PWM脉冲，其中
通道 3（PB8）产生占空比50% 的PWM脉冲
通道 4（PB9）产生占空比25% 的PWM脉冲
本例最好使用示波器观察不同的占空比波形

 *---------------------------------------------------------------------------*/

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



TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
u16 CCR1_Val = 2047;
u16 CCR2_Val = 1535;
u16 CCR3_Val = 1023;
u16 CCR4_Val = 511;
uint32  TIM_Period;

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

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

void delay(uint32 time)
{uint32 i, j;
   
   for(i=0; i<time; i++)
   {
      for(j=0; j<14000; j++);
   }
}

/*******************************************************************************
* 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

  PWM_Configuration();
  while (1)
  {
     ;
  }
  
}

/*******************************************************************************
PWM配置
*******************************************************************************/
void PWM_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;   
  /* TIM1, GPIOA clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOA, ENABLE);

  /* GPIOA Configuration: Channel 1, 2, 3 and 4 as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//GPIO_Mode_Out_PP;//;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

	/* TIM1 Configuration ---------------------------------------------------
   Generates 7 PWM signals with 4 different duty cycles:
   TIM1CLK = 72 MHz, Prescaler = 0, TIM1 counter clock = 72 MHz
   TIM1 frequency = TIM1CLK/(TIM1_Period + 1) = 17.57 KHz
  - TIM1 Channel1 & Channel1N duty cycle = TIM1->CCR1 / (TIM1_Period + 1) = 50% 
  - TIM1 Channel2 & Channel2N duty cycle = TIM1->CCR2 / (TIM1_Period + 1) = 37.5% 
  - TIM1 Channel3 & Channel3N duty cycle = TIM1->CCR3 / (TIM1_Period + 1) = 25%
  - TIM1 Channel4 duty cycle = TIM1->CCR4 / (TIM1_Period + 1) = 12.5% 
  目前关闭了反向通道
  ----------------------------------------------------------------------- */

  /* Time Base configuration */
  TIM_TimeBaseStructure.TIM_Prescaler = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseStructure.TIM_Period = 8191;//4095; //8191=8.789 KHz, 4095=17.57 KHz,频率太高超过人耳听力范围
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;

  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

  /* Channel 1, 2,3 and 4 Configuration in PWM mode */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
  TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCPolarity_Low;//TIM_OCNPolarity_High //关闭反向通道
  TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
  TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;

  TIM_OC1Init(TIM1, &TIM_OCInitStructure);

  TIM_OCInitStructure.TIM_Pulse = CCR2_Val;
  TIM_OC2Init(TIM1, &TIM_OCInitStructure);

  TIM_OCInitStructure.TIM_Pulse = CCR3_Val;
  TIM_OC3Init(TIM1, &TIM_OCInitStructure);

  TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
  TIM_OC4Init(TIM1, &TIM_OCInitStructure);

  /* TIM1 counter enable */
  TIM_Cmd(TIM1, ENABLE);

  /* TIM1 Main Output Enable */
  TIM_CtrlPWMOutputs(TIM1, ENABLE);

  //TIM_TimeBaseStructure.TIM_Period = 4095;
  //TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
   
  //delay(1);
  //delay(10);
  //delay(100);
  //delay(1000);
  TIM_Period=7200;
  TIM_TimeBaseStructure.TIM_Period = TIM_Period;
  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
}


/*******************************************************************************
* 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****/