用PROTEUS仿真单片机与小键盘接口通信

（protues高版本不兼容低版本真是不方便啊）

设计要求：

实现Proteus ISIS中的键盘矩阵与8051微控制器的接口。在上一个项目中，实现了LCD与8051微控制器的接口，可以在上面显示数据和不同的值，接下来的项目将从键盘上获取按键值，并在LCD上显示这些值。

#include<reg51.h>
void cct_init(void);
void delay(int);
void lcdinit(void);
void writecmd(int);
void writedata(char);
void Return(void);
char READ_SWITCHES(void);
char get_key(void);
sbit RowA = P1^0;
sbit RowB = P1^1;
sbit RowC = P1^2; 
sbit RowD = P1^3;  
sbit C1   = P1^4;     
sbit C2   = P1^5;   
sbit C3   = P1^6;    
sbit C4   = P1^7;    
sbit E    = P3^6;  
sbit RS   = P3^7;    
int main(void)
{
   char key;            
   cct_init();      
   lcdinit();            
   while(1)
   { 
     key = get_key();     
     writedata(key);      
   }
}
void cct_init(void)
{
    P0 = 0x00;  
    P1 = 0xf0;   
    P2 = 0x00; 
    P3 = 0x00; 
}
void delay(int a)
{
   int i;
   for(i=0;i<a;i++); 
}
void writedata(char t)
{
   RS = 1;           
   P2 = t;          
   E  = 1;      
   delay(150);
   E  = 0;        
   delay(150);
}
void writecmd(int z)
{
   RS = 0;         
   P2 = z;    
   E  = 1;        
   delay(150);
   E  = 0;       
   delay(150);
}
void lcdinit(void)
{
     delay(15000);
   writecmd(0x30);
     delay(4500);
   writecmd(0x30);
     delay(300);
   writecmd(0x30);
     delay(650);
   writecmd(0x38); 
   writecmd(0x0c); 
   writecmd(0x01);   
   writecmd(0x06);  
}
void Return(void)
{
  writecmd(0x02);
    delay(1500);
}
char READ_SWITCHES(void)    
{    
    RowA = 0; RowB = 1; RowC = 1; RowD = 1;
    if (C1 == 0) { delay(10000); while (C1==0); return '7'; }
    if (C2 == 0) { delay(10000); while (C2==0); return '8'; }
    if (C3 == 0) { delay(10000); while (C3==0); return '9'; }
    if (C4 == 0) { delay(10000); while (C4==0); return '/'; }
    RowA = 1; RowB = 0; RowC = 1; RowD = 1;
    if (C1 == 0) { delay(10000); while (C1==0); return '4'; }
    if (C2 == 0) { delay(10000); while (C2==0); return '5'; }
    if (C3 == 0) { delay(10000); while (C3==0); return '6'; }
    if (C4 == 0) { delay(10000); while (C4==0); return 'x'; }
    RowA = 1; RowB = 1; RowC = 0; RowD = 1; 
    if (C1 == 0) { delay(10000); while (C1==0); return '1'; }
    if (C2 == 0) { delay(10000); while (C2==0); return '2'; }
    if (C3 == 0) { delay(10000); while (C3==0); return '3'; }
    if (C4 == 0) { delay(10000); while (C4==0); return '-'; }
    RowA = 1; RowB = 1; RowC = 1; RowD = 0;
    if (C1 == 0) { delay(10000); while (C1==0); return 'C'; }
    if (C2 == 0) { delay(10000); while (C2==0); return '0'; }
    if (C3 == 0) { delay(10000); while (C3==0); return '='; }
    if (C4 == 0) { delay(10000); while (C4==0); return '+'; }
    return 'n';   
}
char get_key(void)
{
    char key = 'n';
    while(key=='n')
        key = READ_SWITCHES();
    return key;             
}

别的就没啥了，没太大问题的情况下是都可以正常运行的。