. 应用MCS-51单片机设计电子秒表电路；
2. 选用4位LED数码显示，计数时间0-9999s，定时时间可调；
3. 硬件设计根据设计的任务选定合适的单片机，根据控制对象设计接口电路。设计的单元电路必须有工作原理，器件的作用，分析和计算过程；
4. 软件设计根据电路工作过程，画出软件流程图，根据流程图编写相应的程序，进行调试并打印程序清单；
5. 原理图设计根据所确定的设计电路，利用Protel等有关工具软件绘制电路原理图、PCB板图、(Design of electronic stopwatch circuit with MCS-51 microcontroller;
2., select 4 digit LED digital display, counting time 0-9999s, adjustable timing time;
3., the hardware design selects the appropriate microcontroller according to the design task, and designs the interface circuit according to the control object. The designed unit circuit must have the working principle, the function of the device, the analysis and calculation process;
4. software design, according to the circuit work process, draw a software flow chart, according to the flow chart to write the corresponding procedures, debugging, and print list of procedures;
5. schematic design, according to the identified design circuit, the use of Protel and other related software tools to draw circuit schematics, PCB board diagram,)