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修改STM32库函数中的晶振值

作者：时间：2016-11-19 来源：网络

STM32F407的库文件中默认晶振值为25MHz，若外接晶振8MHz，则需修改以下几个地方：

1）修改HSE_VALUE的值

将#define HSE_VALUE ((uint32_t)25) /*!< Value of the External oscillator in Hz */

修改为 #define HSE_VALUE ((uint32_t)8) /*!< Value of the External oscillator in Hz */

2）修改PLL_M的值

将#define PLL_M 25修改为 #define PLL_M 8

3）修改STM32F407工程的Options设置

在Option for target"Flash"窗口中，选择Target页面，修改STMicroelectronics STM32F407VG栏中Xtal(MHz)的值为8.0

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关键词： STM32库函数晶振

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