简单的PWM波形输出配置

只看该作者 · 2011-1-29 22:58

#include "stm32f10x_lib.h"
#include "stm32f10x_conf.h"
/*********************************/
u16             CCR1_Val = 250;
u16             CCR2_Val = 500;

/*********************************/
void RCC_Configuration(void);
void GPIO_Configuration(void);
void NVIC_Configuration(void);
void TIM_Configuration(void);

/*******************/
int main(void)
{
      RCC_Configuration();
      GPIO_Configuration();
      NVIC_Configuration();
      TIM_Configuration();

      while(1);
}

/*****************/
void RCC_Configuration(void)
{
      ErrorStatus             HSEStartUpStatus;

      RCC_DeInit();
      RCC_HSEConfig(RCC_HSE_ON);
      HSEStartUpStatus = RCC_WaitForHSEStartUp();
      if(HSEStartUpStatus == SUCCESS)
      {
               FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
            FLASH_SetLatency(FLASH_Latency_2);
            RCC_HCLKConfig(RCC_SYSCLK_Div1);
            RCC_PCLK2Config(RCC_HCLK_Div1);
            RCC_PCLK1Config(RCC_HCLK_Div4);
            RCC_PLLConfig(RCC_PLLSource_HSE_Div1,RCC_PLLMul_9);
            RCC_PLLCmd(ENABLE);
            while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);
            RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
            while(RCC_GetSYSCLKSource() != 0x08);
      }
      RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);
      RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);
}

/***************/
void GPIO_Configuration(void)
{
      GPIO_InitTypeDef       GPIO_InitStructure;

      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
      GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF_PP;
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_Init(GPIOA, &GPIO_InitStructure);
}

/***********************/
void NVIC_Configuration(void)
{
      #ifdef VECT_TAB_RAM
            NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
      #else
            NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0X0);
      #endif
}

/*****************************/
void TIM_Configuration(void)
{
      TIM_TimeBaseInitTypeDef             TIM_TimeBaseStructure;
      TIM_OCInitTypeDef                      TIM_OCInitStructure;

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

            TIM3的内部时钟频率为36MHz,每个PWM通道的频率经
      (TIM_Period + 1)后为36KHz.
            输出的占空比为:
                     duty cycle = TIM_Pulse/(TIM_Period + 1) * 100%

      *******************************************************/
      TIM_TimeBaseStructure.TIM_Period             = 999;
      TIM_TimeBaseStructure.TIM_Prescaler             = 0;
      TIM_TimeBaseStructure.TIM_ClockDivision       = 0;
      TIM_TimeBaseStructure.TIM_CounterMode       = TIM_CounterMode_Up;

      TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

      //------------- 占空比为 50% 输出波形 ----------------
      TIM_OCInitStructure.TIM_OCMode             = TIM_OCMode_PWM1;
      TIM_OCInitStructure.TIM_OutputState       = TIM_OutputState_Enable;
      TIM_OCInitStructure.TIM_Pulse             = CCR1_Val;
      TIM_OCInitStructure.TIM_OCPolarity       = TIM_OCPolarity_High;

      TIM_OC1Init(TIM3, &TIM_OCInitStructure);
      TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
      //------------- 占空比为 25% 输出波形 ---------------
      TIM_OCInitStructure.TIM_Pulse             = CCR2_Val;
      TIM_OC2Init(TIM3, &TIM_OCInitStructure);
      TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
      //------------------

      TIM_ARRPreloadConfig(TIM3, ENABLE);
      TIM_Cmd(TIM3, ENABLE);
}

/*********************/
#ifdef             DEBUG
void assert_failed(u8 *file, u32 line)
{
      while(1);
}
#endif