STM32F401 AHB时钟大于30MHz 就不运行了，手册数据是84MHz，是什么问题？

按照cubeMX下图的配置，系统时钟配置的代码好像与楼主配置的有点不同：

1. RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
   
2.   RCC_OscInitStruct.HSIState = RCC_HSI_ON;
   
3.   RCC_OscInitStruct.HSICalibrationValue = 16;
   
4.   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
   
5.   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
   
6.   RCC_OscInitStruct.PLL.PLLM = 8;
   
7.   RCC_OscInitStruct.PLL.PLLN = 84;
   
8.   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
   
9.   RCC_OscInitStruct.PLL.PLLQ = 4;
   
10.   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
    
11.   {
    
12.     _Error_Handler(__FILE__, __LINE__);
    
13.   }
    
14. 
    
15.     /**Initializes the CPU, AHB and APB busses clocks
    
16.     */
    
17.   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
    
18.                               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
    
19.   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
    
20.   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
    
21.   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
    
22.   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

复制代码

非常感谢帮助，重新生成的系统时钟配置代码AHB时钟可以跑到42MHz，但是84MHz 不行，
配置代码：
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
  RCC_OscInitStruct.PLL.PLLM = 8;
  RCC_OscInitStruct.PLL.PLLN = 84;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 4;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
  /**Initializes the CPU, AHB and APB busses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV2;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }

RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV2; 42MHz可以，
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1; 84MHz 就不运行了