新手求问F407仿真频率问题

HCHDaLeiGe · 发表于 2018-2-1 08:46:15

请问使用 Simulator 模式进行debug如何修改频率？我尝试改了 target 选项卡里的频率值，但运行代码的时间未发生变化（时间取得是 keil5 右下角的时间，不知道是否准确）。ST-Link debug 模式进行 debug 频率是否为168M？

我在代码里找到了设置时钟频率的位置，尝试修改了几个相关参数，运行时间也未发生明显改变

   PLL_VCO = (HSE_VALUE or HSI_VALUE / PLLM) * PLLN
   SYSCLK = PLL_VCO / PLLP
*=============================================================================
  *=============================================================================
  *                   Supported STM32F40xxx/41xxx devices
  *-----------------------------------------------------------------------------
  *       System Clock source                   | PLL (HSE)
  *-----------------------------------------------------------------------------
  *       SYSCLK(Hz)                            | 168000000
  *-----------------------------------------------------------------------------
  *       HCLK(Hz)                            | 168000000
  *-----------------------------------------------------------------------------
  *       AHB Prescaler                         | 1
  *-----------------------------------------------------------------------------
  *       APB1 Prescaler                      | 4
  *-----------------------------------------------------------------------------
  *       APB2 Prescaler                      | 2
  *-----------------------------------------------------------------------------
  *       HSE Frequency(Hz)                   | 25000000
  *-----------------------------------------------------------------------------
  *       PLL_M                               | 25
  *-----------------------------------------------------------------------------
  *       PLL_N                               | 336
  *-----------------------------------------------------------------------------
  *       PLL_P                               | 2
  *-----------------------------------------------------------------------------
  *       PLL_Q                               | 7
  *-----------------------------------------------------------------------------
  *       PLLI2S_N                            | NA
  *-----------------------------------------------------------------------------
  *       PLLI2S_R                            | NA
  *-----------------------------------------------------------------------------
  *       I2S input clock                      | NA
  *-----------------------------------------------------------------------------
  *       VDD(V)                               | 3.3
  *-----------------------------------------------------------------------------
  *       Main regulator output voltage       | Scale1 mode
  *-----------------------------------------------------------------------------
  *       Flash Latency(WS)                   | 5
  *-----------------------------------------------------------------------------
  *       Prefetch Buffer                      | ON
  *-----------------------------------------------------------------------------
  *       Instruction cache                   | ON
  *-----------------------------------------------------------------------------
  *       Data cache                            | ON
  *-----------------------------------------------------------------------------
  *       Require 48MHz for USB OTG FS,       | Disabled
  *       SDIO and RNG clock                   |
  *-----------------------------------------------------------------------------
  *=============================================================================