诡异现象之TIM2 ——大侠救命

只看该作者 · 2010-3-26 21:50

用tim2做个250us的定时
用来把led翻转  本来是2s的翻转
但现在实际是1s翻转
看了半天不知道为什么
各位大侠帮分析下，程序如下：
谢谢大家！
//////////////////////////////////////////////////////////////////////
void TIM2_config(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
  TIM_TimeBaseInitTypeDef  TIM_BaseInitStructure;
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); //使能时钟
  NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel; //使能中断
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
//时基模块设置
/////////////////////////////////////////////////////////////////
//
//中断频率= apb1 clock/(perscaler+1) /period
//
/////////////////////////////////////////////////////////////////
//TIM2 使用内部时钟
//TIM_InternalClockConfig(TIM2);
//TIM2基本设置
//设置预分频器分频系数35，即APB1=72M/2, TIM1_CLK=36M/36=1MHz
//TIM_Period（TIM2_ARR）=250，计数器向上计数到250后产生更新事件，计数值归零
//向上计数模式
//TIM_RepetitionCounter(TIM2_RCR)=0，每次向上溢出都产生更新事件
// wave文件为4KHz mono pcm编码，所以取中断时间为250us  4kHz=1M/250
TIM_DeInit(TIM2);
TIM_BaseInitStructure.TIM_Period = 250;
TIM_BaseInitStructure.TIM_Prescaler = 35;//0
TIM_BaseInitStructure.TIM_ClockDivision = 0;
TIM_BaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_BaseInitStructure.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM2, &TIM_BaseInitStructure);
//TIM_PrescalerConfig(TIM2, 35, TIM_PSCReloadMode_Immediate);//35+1预分频
//清中断，以免一启用中断后立即产生中断
TIM_ClearFlag(TIM2, TIM_FLAG_Update);
//使能TIM1中断源
TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
//TIM1总开关：开启
TIM_Cmd(TIM2, ENABLE);
}
//////////////////////////////////////////////////////////////////////
void RCC_Configuration(void)
{
  ErrorStatus HSEStartUpStatus;
  /* RCC system reset(for debug purpose) */
  RCC_DeInit();
  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);
  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();
  if(HSEStartUpStatus == SUCCESS)
  {
/* Enable Prefetch Buffer */
FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
/* Flash 2 wait state */
FLASH_SetLatency(FLASH_Latency_2);

/* HCLK = SYSCLK */
RCC_HCLKConfig(RCC_SYSCLK_Div1);

/* PCLK2 = HCLK */
RCC_PCLK2Config(RCC_HCLK_Div1);
/* PCLK1 = HCLK/2 */
RCC_PCLK1Config(RCC_HCLK_Div2);
/* PLLCLK = 8MHz * 9 = 72 MHz */
RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);
/* Enable PLL */
RCC_PLLCmd(ENABLE);
/* Wait till PLL is ready */
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
{
}
/* Select PLL as system clock source */
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
/* Wait till PLL is used as system clock source */
while(RCC_GetSYSCLKSource() != 0x08)
{
}
  }
}
/////////////////////////////////////////////////////////////////////////
void NVIC_Configuration(void)
{
//  NVIC_InitTypeDef NVIC_InitStructure;
  NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
  /* Configure the NVIC Preemption Priority Bits */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
//  NVIC_InitStructure.NVIC_IRQChannel = SDIO_IRQChannel;
//  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
//  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
//  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
//  NVIC_Init(&NVIC_InitStructure);
}
////////////////////////////////////////////////////////////////////////

中断程序

void TIM2_IRQHandler(void)
{
  vu16 i;
if(TIM_GetITStatus(TIM2,TIM_IT_Update)!=RESET)
  {
TIM_ClearITPendingBit(TIM2,TIM_IT_Update);
m++;
if(m>=8000)
{
m=0;
itcount++;
  i= GPIO_ReadOutputData(GPIOF);
i=i^0x0200;
GPIO_Write(GPIOF,i);
}
  }
}

1万 · 2010-3-26 22:17

请注意，按照你的配置TIM_CLK是72MHz而不是36MHz。

这个问题已经讨论过无数次，请搜索一下吧。

只看该作者 · 2010-3-26 22:27

可是这里设为div/2 了啊？
void RCC_Configuration(void)
{
  ErrorStatus HSEStartUpStatus;
  /* RCC system reset(for debug purpose) */
  RCC_DeInit();

  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);

  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();

  if(HSEStartUpStatus == SUCCESS)
  {
/* Enable Prefetch Buffer */
FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

/* Flash 2 wait state */
FLASH_SetLatency(FLASH_Latency_2);

/* HCLK = SYSCLK */
RCC_HCLKConfig(RCC_SYSCLK_Div1);

/* PCLK2 = HCLK */
RCC_PCLK2Config(RCC_HCLK_Div1);

/* PCLK1 = HCLK/2 */
RCC_PCLK1Config(RCC_HCLK_Div2);//、、、、、

/* PLLCLK = 8MHz * 9 = 72 MHz */
RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

/* Enable PLL */
RCC_PLLCmd(ENABLE);

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

/* Select PLL as system clock source */
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

/* Wait till PLL is used as system clock source */
while(RCC_GetSYSCLKSource() != 0x08)
{
}
  }

}