1硬件连接图3-1所示为简易计算器的电路原理图
P3口用于键盘输入，接4*4矩阵键盘，键值与键盘的对应表如表----所示，p0口和p2口用于显示，p2口用于显示数值的高位，po口用于显示数值的低位
图3-1简易计算器电路原理图键值与功能对应表1/25键值0123456789+-×/=ON/C功能0123456789+-×÷=清零表3-13
2计算器的软件设计#include//头文件#defineuintunsignedint//#defineucharunsignedcharsbitlcden=P2^3
//定义引脚sbitrs=P2^4
sbitrw=P2^0
sbitbusy=P0^7
chari,j,temp,num,num_1
longa,b,c
//a,第一个数b,第二个数c,得数floata_c,b_c
ucharflag,fuhao
//flag表示是否有符号键按下，fuhao表征按下的是哪个符号ucharcodetable[]={7,8,9,0,4,5,6,0,1,2,3,0,0,0,0,0}
2/25ucharcodetable1[]={7,8,9,0x2f-0x30,4,5,6,0x2a-0x30,1,2,3,0x2d-0x30,0x01-0x30,0,0x3d-0x30,0x2b-0x30}
voiddelay(ucharz>//延迟函数{uchary
z-->for(y=0
}voidcheck(>//判断忙或空闲{do{P0=0xFF
//指令rw=1
//读lcden=0
//禁止读写delay(1>
//等待，液晶显示器处理数据lcden=1
//允许读写}while(busy==1>
//判断是否为空闲，1为忙，0为空闲3/25}voidwrite_com(ucharcom>//写指令函数{P0=com
