如题，下面贴上我的时钟设置代码：
#define PLL_SOURCE_HSI        // HSI (~8MHz) used to clock the PLL, and the PLL is used as system clock source
static void SetSysClock(void)
{
  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;
 
  /* SYSCLK, HCLK, PCLK configuration ----------------------------------------*/
#if defined (PLL_SOURCE_HSI)
  /* At this stage the HSI is already enabled */
  /* Enable Prefetch Buffer and set Flash Latency */
  FLASH->ACR = FLASH_ACR_PRFTBE | FLASH_ACR_LATENCY;
 
  /* HCLK = SYSCLK */
  RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
     
  /* PCLK = HCLK */
  RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE_DIV1;
  /* PLL configuration = (HSI/2) * 12 = ~48 MHz */
  RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
  RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSI_Div2 | RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLMULL12);
           
  /* 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)RCC_CFGR_SWS_PLL)
  {
  }
#else
 #if defined (PLL_SOURCE_HSE)
  /* Enable HSE */   
  RCC->CR |= ((uint32_t)RCC_CR_HSEON);
 #elif defined (PLL_SOURCE_HSE_BYPASS)
  /* HSE oscillator bypassed with external clock */   
  RCC->CR |= (uint32_t)(RCC_CR_HSEON | RCC_CR_HSEBYP);
 #endif /* PLL_SOURCE_HSE */
  
  /* 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 and set Flash Latency */
    FLASH->ACR = FLASH_ACR_PRFTBE | FLASH_ACR_LATENCY;
 
    /* HCLK = SYSCLK */
    RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
     
    /* PCLK = HCLK */
    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE_DIV1;
    /* PLL configuration = HSE * 6 = 48 MHz */
    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_PREDIV1 | RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLMULL6);
           
    /* 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)RCC_CFGR_SWS_PLL)
    {
    }
  }
  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 /* PLL_SOURCE_HSI */ 
}
 
 
当我调试到
RCC->CR |= RCC_CR_PLLON;这条语句的时候，仿真器就不能调试了
不知是怎么回事？

今天搞定这个问题了，原因是我的VDDA没有上电

很好的问答。。。

刚才试了下内部时钟，发现死在了
while((RCC->CR & RCC_CR_PLLRDY) == 0)
跟楼主情况差不多，不知什么原因

请问楼主，VDDA没有上电  的意思是硬件有问题吗？还是代码没有讲VDDA打开？