51单片机LCD计算器程序

以下是一个基于51单片机的LCD计算器程序，可以实现加、减、乘、除四则运算：

#include<reg51.h>
#define uchar unsigned char
#define uint unsigned int

sbit RS = P2^6;  //LCD1602控制引脚
sbit RW = P2^5;
sbit EN = P2^7;
sbit KEY1 = P3^0;  //按键
sbit KEY2 = P3^1;
sbit KEY3 = P3^2;
sbit KEY4 = P3^3;
sbit KEY5 = P3^4;

uchar num1[5], num2[5], result[8];  //存储数字和结果的数组
uchar op;  //运算符

void delay(uint t)  //延时函数
{
    uint i, j;
    for(i=0; i<t; i++)
        for(j=0; j<120; j++);
}

void write_com(uchar com)  //写指令函数
{
    RS = 0;
    RW = 0;
    P0 = com;
    EN = 1;
    delay(5);
    EN = 0;
}

void write_data(uchar dat)  //写数据函数
{
    RS = 1;
    RW = 0;
    P0 = dat;
    EN = 1;
    delay(5);
    EN = 0;
}

void init_LCD()  //LCD初始化函数
{
    write_com(0x38);  //8位数据接口，2行显示，5x7点阵
    write_com(0x0c);  //显示开，光标关，闪烁关
    write_com(0x06);  //文字不动，光标自动右移
    write_com(0x01);  //清屏，光标回到起始位置
}

void write_string(uchar x, uchar y, uchar *str)  //写字符串函数
{
    uchar i=0;
    if(x<16)
    {
        if(y==0)  //第一行
            write_com(0x80+x);
        else  //第二行
            write_com(0x80+0x40+x);
        while(str[i]!='\0')
        {
            write_data(str[i]);
            i++;
        }
    }
}

void get_num1()  //获取第一个数字
{
    uchar i=0;
    while(KEY5==0)  //等待按键松开
    {
        if(KEY1==0)  //数字1
        {
            num1[i] = '1';
            i++;
            write_string(i-1, 0, "1");
            delay(500);
        }
        else if(KEY2==0)  //数字2
        {
            num1[i] = '2';
            i++;
            write_string(i-1, 0, "2");
            delay(500);
        }
        else if(KEY3==0)  //数字3
        {
            num1[i] = '3';
            i++;
            write_string(i-1, 0, "3");
            delay(500);
        }
        else if(KEY4==0)  //加号
        {
            op = '+';
            write_string(i, 0, "+");
            delay(500);
            break;
        }
    }
}

void get_num2()  //获取第二个数字
{
    uchar i=0;
    while(KEY5==0)  //等待按键松开
    {
        if(KEY1==0)  //数字1
        {
            num2[i] = '1';
            i++;
            write_string(i, 0, "1");
            delay(500);
        }
        else if(KEY2==0)  //数字2
        {
            num2[i] = '2';
            i++;
            write_string(i, 0, "2");
            delay(500);
        }
        else if(KEY3==0)  //数字3
        {
            num2[i] = '3';
            i++;
            write_string(i, 0, "3");
            delay(500);
        }
        else if(KEY4==0)  //减号
        {
            op = '-';
            write_string(i, 0, "-");
            delay(500);
            break;
        }
    }
}

void calculate()  //计算结果
{
    uint n1=0, n2=0, res=0;
    n1 = (num1[0]-48)*100 + (num1[1]-48)*10 + (num1[2]-48);
    n2 = (num2[0]-48)*100 + (num2[1]-48)*10 + (num2[2]-48);
    switch(op)
    {
        case '+':
            res = n1 + n2;
            break;
        case '-':
            res = n1 - n2;
            break;
        case '*':
            res = n1 * n2;
            break;
        case '/':
            res = n1 / n2;
            break;
    }
    sprintf(result, "%d", res);  //将结果转换为字符串
    write_string(0, 1, result);
}

void main()
{
    init_LCD();
    write_string(0, 0, "CALCULATOR");
    while(1)
    {
        while(KEY5==1);  //等待按键按下
        if(KEY1==0)  //乘号
        {
            op = '*';
            write_string(3, 0, "*");
            delay(500);
            get_num1();
            get_num2();
            calculate();
        }
        else if(KEY2==0)  //除号
        {
            op = '/';
            write_string(3, 0, "/");
            delay(500);
            get_num1();
            get_num2();
            calculate();
        }
    }
}

需要注意的是，该程序只能进行三位数以内的整数运算，如果需要支持更大的数或实现浮点数运算，需要进行相应的修改。