采用汇编写的可调定时器，可定时999秒，采用数码管显示，自己可定时，改动源程序即可调最长定时时间，用Protues仿真。-The adjustable timer written in assembler, may from time to time of 999 seconds, the digital display, timing, and changes to the source code can be adjusted to the maximum timing Protues si