1、功能说明

    /* 简单描述工程功能 */
        这个例程配置并演示NVIC优先级设置


2、使用环境

        软件开发环境：KEIL MDK-ARM V5.34.0.0
                      IAR EWARM 8.50.1
    
        硬件环境：基于评估板N32G401C8L7-STB V1.0开发


3、使用说明

    /* 描述相关模块配置方法；例如:时钟，I/O等 */
        SystemClock：72MHz

        USART: TX-PA9, RX-PA10，波特率115200
        EXIT：PA0为浮空输入模式，外部中断线 - EXIT_LINE0，开启外部中断，优先级为0
        SysTick：中断优先级设置为0

    /* 描述Demo的测试步骤和现象 */
        1.编译后下载程序复位运行；
        2.正常情况下打印SysTick中断信息，当按键外部中断和SysTick中断同时触发时，修改SysTick中断优先级为2，并打印相关信息，程序运行正常；


4、注意事项


1. Function description
    /* A brief description of the engineering function */
    This routine configures and demonstrates NVIC priority Settings

2. Use environment

    Software development environment: KEIL MDK-ARM V5.34.0.0
                                      IAR EWARM 8.50.1
    Hardware environment: Developed based on the evaluation board N32G401C8L7-STB V1.0
        
3. Instructions for use    
    /* Describe the related module configuration method; For example: clock, I/O, etc. */
    SystemClock: 72MHZ
    USART: TX-PA9, RX-PA10, baud rate 115200
    EXIT: PA0 is floating input mode, external interrupt line -exit_line0, external interrupt is enabled, and the priority is 0
    SysTick: Set the interrupt priority to 0
    
    /* Describes the test steps and symptoms of Demo */
    1. Reset and run the downloaded program after compilation;
    2. In normal cases, SysTick interrupt information is displayed. If both the external interrupt and SysTick interrupt are triggered at the same time, change the SysTick interrupt priority to 2 and print related information.

4. Precautions
    None