1.上电后，在数码管或者液晶上显示数字“0000”；(5分)

2.实现计时，单位为0.1S，由1计数到50，循环反复，即从“0000”显示至“0050”，后循环；(10分)

3.编写程序，使可通过按键，设置计数周期，范围为0~6000可调；(15分)

4.编写程序，使可通过按键，实现计数暂停、继续与复位的功能；(25分)

5.编写程序，通过数码管或液晶实现人机交互，即在通过按键设置计数周期时，在其上面显示当前设置的周期数；(15分)

6.*附加要求：使系统有序，即在计数中与计数暂停的时候不可设置计数周期，只有在复位之后才可进行计数周期的设置；

-1. After power up, display the number " 0000"　in the digital tube or LCD on　(5 points) 2. timing, and the unit is 0.1S, by one count to 50, the cycle repeated,　" 0000"　display to the " 0050 " After the circulation　(10 points) 3. Write a program that by pressing a button, set the counting period, adjustable in the range 0 to 6000　(15 points) 4. Write a program that by pressing a button, to achieve counts pause, resume and reset functions　(25 points) 5. Write a program implemented by digital tube or LCD computer interaction, that is, when the counting period set by the button to display the number of cycles currently set thereon　(15 points) 6.* Additional requirements: the system ordered, namely in the count and the count can not be set to pause when the counting period, can be conducted only after the reset cycle count set