如何确认总线时钟配置正确？

我在使用STM32F105外接8M,为了验证我的总线时钟配置，我分别用TIM1,和TIM3做了一个测试代码

void TimerTestInit(void)
{
        TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
        NVIC_InitTypeDef         NVIC_InitStructure;

        RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
        //NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
        NVIC_InitStructure.NVIC_IRQChannel = TIM1_UP_IRQn;  
        NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
        NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;   
        NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  
        NVIC_Init(&NVIC_InitStructure);

  TIM_TimeBaseStructure.TIM_Period = 10000;
  TIM_TimeBaseStructure.TIM_Prescaler =7200;  
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

  TIM_ITConfig(TIM1,TIM_IT_Update,ENABLE);
  TIM_Cmd(TIM1, ENABLE);  
       
        //tim3
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
       

        //³õʼ»¯TIM2 (×¢£ºTIM2ʱÖÓΪ×ÜÏßʱÖÓµÄÁ½±¶£¬Ò²¾ÍÊÇ72MHz,ÏéÇé²Î¿¼STM32²Î¿¼ÊÖ²á7.2½Ú)
        TIM_TimeBaseStructure.TIM_Period =10000;                        //ÉÏÏÞÖµ
        TIM_TimeBaseStructure.TIM_Prescaler = 7200;                //Ô¤·ÖƵ
        TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1  ;        //Â˲¨Æ÷·ÖƵ
        TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;        //
        TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
       
       
        NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
        NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
        NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
        NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
        NVIC_Init(&NVIC_InitStructure);

        TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);//ÖжÏÔÊÐí
        TIM_Cmd(TIM3, ENABLE);       
}

void TIM1_UP_IRQHandler(void)  
{  
        TIM_ClearITPendingBit(TIM1, TIM_FLAG_Update);
        BEEP_FLASH;
}  
void TIM3_IRQHandler(void)
{
        TIM_ClearITPendingBit(TIM3, TIM_IT_Update);       
        LED_FLASH;
}

观察发现TIM1的中断频率是2秒，TIM3的中断频率是1秒；我配置的APB1总线频率是36M,APB2总线频率为72M
所以TIM3的中断频率应该是正确的，就不知道TIM1的中断频率为什么只有2秒？？？

再贴上时钟配置：

复制

/**

  * [url=home.php?mod=space&uid=247401]@brief[/url]  Sets System clock frequency to 72MHz and configure HCLK, PCLK2

  *         and PCLK1 prescalers.

  * [url=home.php?mod=space&uid=536309]@NOTE[/url]   This function should be used only after reset.

  * @param  None

  * @retval None

  */

static void SetSysClockTo72(void)

{

  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;



  /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/

  /* Enable HSE */

  RCC->CR |= ((uint32_t)RCC_CR_HSEON);



  /* Wait till HSE is ready and if Time out is reached exit */

  do

  {

    HSEStatus = RCC->CR & RCC_CR_HSERDY;

    StartUpCounter++;

  } while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));



  if ((RCC->CR & RCC_CR_HSERDY) != RESET)

  {

    HSEStatus = (uint32_t)0x01;

  }

  else

  {

    HSEStatus = (uint32_t)0x00;

  }



  if (HSEStatus == (uint32_t)0x01)

  {

    /* Enable Prefetch Buffer */

    FLASH->ACR |= FLASH_ACR_PRFTBE;



    /* Flash 2 wait state */

    FLASH->ACR &= (uint32_t)((uint32_t)~FLASH_ACR_LATENCY);

    FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_2;





    /* HCLK = SYSCLK */

    RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;



    /* PCLK2 = HCLK */

    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;



    /* PCLK1 = HCLK */

    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV2;



#ifdef STM32F10X_CL

    /* Configure PLLs ------------------------------------------------------*/

    /* PLL2 configuration: PLL2CLK = (HSE / 5) * 8 = 40 MHz */

    /* PREDIV1 configuration: PREDIV1CLK = PLL2 / 5 = 8 MHz */



    RCC->CFGR2 &= (uint32_t)~(RCC_CFGR2_PREDIV2 | RCC_CFGR2_PLL2MUL |

                              RCC_CFGR2_PREDIV1 | RCC_CFGR2_PREDIV1SRC);



    /* Configure PLLs ------------------------------------------------------*/

    /* PLL2 configuration: PLL2CLK = (HSE / 2) * 10 = 40 MHz */

    /* PREDIV1 configuration: PREDIV1CLK = PLL2 / 5 = 8 MHz */

    RCC->CFGR2 |= (uint32_t)(RCC_CFGR2_PREDIV2_DIV2 | RCC_CFGR2_PLL2MUL10 |

                             RCC_CFGR2_PREDIV1SRC_PLL2 | RCC_CFGR2_PREDIV1_DIV5);







    /* Enable PLL2 */

    RCC->CR |= RCC_CR_PLL2ON;

    /* Wait till PLL2 is ready */

    while((RCC->CR & RCC_CR_PLL2RDY) == 0)

    {

    }





    /* PLL configuration: PLLCLK = PREDIV1 * 9 = 72 MHz */

    RCC->CFGR &= (uint32_t)~(RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLSRC | RCC_CFGR_PLLMULL);

    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLSRC_PREDIV1 |

                            RCC_CFGR_PLLMULL9);

#else

    /*  PLL configuration: PLLCLK = HSE * 9 = 72 MHz */

    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE |

                                        RCC_CFGR_PLLMULL));

    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMULL9);

#endif /* STM32F10X_CL */



    /* Enable PLL */

    RCC->CR |= RCC_CR_PLLON;



    /* Wait till PLL is ready */

    while((RCC->CR & RCC_CR_PLLRDY) == 0)

    {

    }



    /* Select PLL as system clock source */

    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));

    RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;



    /* Wait till PLL is used as system clock source */

    while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)0x08)

    {

    }

  }

  else

  { /* If HSE fails to start-up, the application will have wrong clock

         configuration. User can add here some code to deal with this error */

  }

}





#endif

只能测试总线的读写时间了