1、功能说明
    1、LPTIM 定时产生EXTI24，唤醒CPU进行IO翻转
2、使用环境
    软件开发环境：  KEIL MDK-ARM V5.30.0.0
    硬件环境：      基于N32L43XM-STB开发
3、使用说明
    系统配置；
        1、时钟源：
            HSE=8M,PLL=108M,AHB=108M,APB1=27M,APB2=54M,LPTIM CLK=LSI
        2、中断：
            LPTIM周期触发EXTI24中断，唤醒CPU
        3、端口配置：
            PB0选择为IO输出
        4、LPTIM：
            LPTIM连续定时模式
    使用方法：
        1、编译后打开调试模式，可观察到PB0引脚周期性翻转，且CPU不断进入低功耗模式
4、注意事项
    无


1. Function description
     1. LPTIM generates EXTI24 regularly, wakes up the CPU for IO flipping
2. Use environment
     Software development environment: KEIL MDK-ARM V5.30.0.0
     Hardware environment: Based on N32L43XM-STB development
3. Instructions for use
     System Configuration;
         1. Clock source:
             HSE=8M,PLL=108M,AHB=108M,APB1=27M,APB2=54M,LPTIM CLK=LSI
         2. Interrupt:
             LPTIM cycle triggers EXTI24 interrupt, wakes up CPU
         3. Port configuration:
             PB0 is selected as IO output
         4. LPTIM:
             LPTIM Continuous Timing Mode
     Instructions:
         1. Turn on the debug mode after compiling, and the PB0 pin can be observed to periodically toggle, and the CPU continues to enter the low-power mode
4. Attention
     none