字符液晶显示的频率计.doc

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目录
1设计要求························································2
2设计方案与论证··················································2
2.1设计的思路··················································2
2.2总体方案····················································2
2.3总体框图····················································3
3设计原理及电路图················································3
3.1硬件原理·····················································3
3.1.1AT89C51介绍···············································3
3.1.2单片机最小系统·············································4
3.1.3液晶显示电路···············································4
3.2电路图······················································5
3.2.1液晶显示电路···············································5
3.2.2时钟电路···················································6
3.2.3控制电路···················································6
3.2.4字符液晶显示频率计的完整电路图·····························7
3.3软件设计···················································7
3.3.1软件环境···················································7
3.3.2软件原理···················································8
3.3.3软件流程图·················································8
4器件清单······················································8
5器件识别与检测··············································9
6控制系统实现·················································9
6.1软件编程···················································9
6.2KeilC与Proteus的联调及仿真结果·····················12
7设计心得························································13
8参考文献························································13

1.设计要求
（1）单片机通过I/O口接收输入信号。
（2）单片机要通过I/O口控制液晶的初始化、显示方式以及要显示的字符。
（3）液晶屏上能够完成部分数字或常用字符的显示。
（4）能通过改变程序，提高测量精度。
（5）设计字符液晶频率计的电路图，并用proteus软件进行仿真。
（6）用单片机的c语言编写程序并导入单片机中进行模拟仿真。
2.设计方案与论证
2.1设计的思路
（1）单片机部分：
考虑到目前所学习的内容和设计的目的，决定选取AT89C51.此单片机虽然属于低端机型，但足以满足设计的要求。选取其它的高端机型有些浪费。
（2）显示部分：
该课程设计要求能够完成部分数字和常用字符的显示。若用数码管只能显示0~F，不能显示其他的字符和符号，所以不能用数码管。而选用LCD1602恰好符合要求，所以应用LCD1602。
综上可得：采用定时器T1实现外部信号的频率输入，并利用T1计数器的计数功能和T0定时器