本源码为基于STM32低功耗原理实验程序，主要实现根据最低电源消耗、最快速启动时间和可用的唤醒源等条件，选定一个最佳的低功耗模式(The source code is an external interrupt program based on STM32, and the point to focus on is the corresponding port clock configuration, pin initialization configuration, and interrupt