1
摘要 2
一、课题背景与设计要求...............................................................................................................2
1、设计要求与设计说明.........................................................................................................2
2、课题分析 ............................................................................................................................3
3、方案论证 ............................................................................................................................3
4、方案选择 ............................................................................................................................4
二、设计思路与原理.......................................................................................................................5
1、 系统方框图.......................................................................................................................5
2 、总体设计思路与工作原理...............................................................................................6
三．各主要电路及部件工作原理...................................................................................................6
1， 2Hz 脉冲及分频电路（NE555、JK 触 发器构成 T'触发器） ......................................6
2. 循环控制部分（74ls194 移位寄存器）与上电复位电路 ..............................................7
3. 计数电路 ............................................................................................................................9
4. 输出控制电路及译码显示电路.......................................................................................10
四． 总体调试及仿真...................................................................................................................11
1. NE555 与分频器的调试....................................................................................................11
2. 复位电路调试...................................................................................................................12
3. 74ls194 模式选择移位寄存器调试................................................................................12
4. 74ls161 十进制计数器调试............................................................................................12
5. 译码显示电路调试...........................................................................................................13
五． 元器件清单 ..........................................................................................................................13
六． 设计总结 ..............................................................................................................................14
暂无 ................................................................................................................................................14
参考文献 ........................................................................................................................................14
