1、功能说明

    /* 简单描述工程功能 */
        这个例程配置并演示设置不同的系统时钟，并用MCO从PA8输出出来


2、使用环境

    /* 硬件环境：工程对应的开发硬件平台 */
        开发板：N32G030C8L7-STB V1.0
        

3、使用说明

    /* 描述相关模块配置方法；例如:时钟，I/O等 */
        USART：TX - PA9，波特率115200
        GPIO：PA8 - 复用为MC0时钟输出

    /* 描述Demo的测试步骤和现象 */
        1.编译后下载程序复位运行；
        2.分别配置系统时钟为HSI、HSE、PLL，分别使用串口打印出当前SYSCLK、HCLK、PCLK1、PCLK2等信息，并且可以使用PA8复用引脚输出时钟PLL 2分频，用示波器查看时钟频率；


4、注意事项
   使用LSE或LSI作系统时钟源时，由于时钟频率过低会导致无法打印，需屏蔽打印函数，通过MCO查看频率

1. Function description

     /* Briefly describe the engineering function */
     This example configures and demonstrates the setting of different system clocks, and uses MCO to output from PA8


2. Use environment

      
     /* Hardware environment: development hardware platform corresponding to the project */
     Development board: N32G030C8L7-STB V1.0

3. Instructions for use

     /* Describe the configuration method of related modules; for example: clock, I/O, etc. */
     USART: TX-PA9, baud rate 115200
     GPIO: PA8-multiplexed as MC0 clock output

     /* Describe the test steps and phenomena of Demo */
     1. After compiling, download the program to reset and run;
     2. Configure the system clock as HSI, HSE, and PLL respectively, and use the serial port to print out the current SYSCLK, HCLK, PCLK1, PCLK2 and other information, and use the PA8 multiplex pin to output the clock PLL 2 frequency division and view clock frequency with an oscilloscope;


4. Attention
    when using LSE as the system clock source, the clock frequency is too low, which will lead to failure to print, you need to block the pint function, and view the frequency through the MCO.