说明：  仅只占用一个定时器，代码量仅200多字节，最多可管理255个任务，使用简单方便。本实例基于stm8s103，通过修改定时器的具体代码可移植到其它单片机上。
(Only one timer is used, and the code volume is only 200 bytes. It can manage 255 tasks at most. It is simple and convenient to use. This example is based on stm8s103, and can be transplanted to other microcontrollers by modifying the specific code of the timer.)