关于STM32F072启动的问题,MCU不能工作

qq4056 · 发表于 2019-6-6 20:01:24

[mw_shl_code=c,true]static void SetSysClock(void)
{
  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;

  /* SYSCLK, HCLK, PCLK configuration ----------------------------------------*/
  /* Enable HSE */
//RCC->CR |= ((uint32_t)RCC_CR_HSEON);
      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 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 * 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 */
  }
}[/mw_shl_code]由于所用的DEMO版需要，我把第7行改为第8行，程序一直在第10行到第14行的地方循环执行，MCU无法正常工作，请问各位问题出在哪？