2.1 硬件系统总体设计..............................................................................................6
2.2 软件系统总体设计..............................................................................................8
3 硬件器件的选择......................................................................................................8
3.1 单片机的选择......................................................................................................8
3.2 电源电路器件的选择..........................................................................................8
3.3 显示电路芯片的选择..........................................................................................9
3.4 D/A 和 A/D 转换电路滤波放大电路的选择 ....................................................10
3.5 串口芯片的选择................................................................................................11
3.6 电平转换电路....................................................................................................12
4 硬件电路图分析......................................................................................................12
4.1 复位电路设计.......................................................................................................12
4.2 电源电路的设计...................................................................................................13
4.3 电平转换电路的设计方案................................................................................17
4.4 晶振电路的布局................................................................................................19
4.6 键盘电路设计....................................................................................................20
4.7 串口通信电路硬件设计....................................................................................21
4.8 A/D 转换电路.....................................................................................................22
5 系统软件设计..........................................................................................................25
5.1 键盘功能的实现................................................................................................25
5.1.1
键盘输入的软件问题
.................................................................................25
5.1.2
主程序设计
..................................................................................................26
5.2 显示电路程序设计............................................................................................26
5.3 显示状态计算子程序........................................................................................27
5.4 A/D 和 D/A 转换程序设计...............................................................................28
5.5 串口通信软件设计............................................................................................29
5.5 压力采集子程序...............................................................................................30
5.6 干扰及其应用.................................................................................................31
5
.
6
.
1
硬件措施
...............................................................................................32
5.6.2
软件措施
.....................................................................................................32
5.6 与微机的通信 ...................................................................................................33
6 全文总结................................................................................................................33
参考文献......................................................................................................................35