概要

1.系统通过4x4的矩阵键盘输入数字及运算符。 
2.可以进行4位十进制数以内的加法运算，如果计算结果超过4位十进制数，则屏幕显示E
3.可以进行加法以外的计算 (乘、除、减) 。

仿真图

 

 

部分代码

void main(){while(1){keyScan();                       pd();                                       display(num);                       }
}
void keyAdd(){              if(numKey<10000){num=num*10+numKey;numKey=10000;}
}
void pd(){keyAdd();                               if(fuhao=='c'){                       num=0;num0=0;fuhao0='0';fuhao='0';}if(fuhao=='+'){                       fuhao0='+';                       fuhao='0';                       num0=num;                       num=0;}if(fuhao=='-'){                               fuhao0='-';fuhao='0';num0=num;num=0;}       if(fuhao=='*'){                               fuhao0='*';fuhao='0';num0=num;num=0;}       if(fuhao=='/'){                       fuhao0='/';fuhao='0';num0=num;num=0;}if(fuhao=='='){                       if(fuhao0=='+')num=num0+num;else if(fuhao0=='-')num=num0-num;else if(fuhao0=='*')num=num0*num;else if(fuhao0=='/')num=num0/num;fuhao='0';num0=0;}
}
void keyScan(){P3=0xef;//1110 1111if(!P3_3){numKey=7;while(!P3_3);}if(!P3_2){numKey=8;while(!P3_2);}if(!P3_1){numKey=9;while(!P3_1);}if(!P3_0){fuhao='/';while(!P3_0);}P3=0xdf;if(!P3_3){numKey=4;while(!P3_3);}if(!P3_2){numKey=5;while(!P3_2);}if(!P3_1){numKey=6;while(!P3_1);}if(!P3_0){fuhao='*';while(!P3_0);}P3=0xbf;if(!P3_3){numKey=1;while(!P3_3);}if(!P3_2){numKey=2;while(!P3_2);}if(!P3_1){numKey=3;while(!P3_1);}if(!P3_0){fuhao='-';while(!P3_0);}P3=0x7f;if(!P3_3){fuhao='c';while(!P3_3);}if(!P3_2){numKey=0;while(!P3_2);}if(!P3_1){fuhao='=';while(!P3_1);}if(!P3_0){fuhao='+';while(!P3_0);}
}
void display(int num1){if(num1<= 9999)       {n4=num1%10;n3=num1/10%10;n2=num1/100%10;n1=num1/1000%10;P2=0x01;P0=duan[n1];DelayXms(4);P2=0x02;P0=duan[n2];DelayXms(4);P2=0x04;P0=duan[n3];DelayXms(4);P2=0x08;P0=duan[n4];DelayXms(4);}else{P2=0x01;P0=duan[10];DelayXms(4);P2=0x02;P0=duan[10];DelayXms(4);P2=0x04;P0=duan[10];DelayXms(4);P2=0x08;P0=duan[10];DelayXms(4);}}
void DelayXms(unsigned int x)               
{        unsigned char i, j;while(x--){        i = 2;j = 239;do{while (--j);}while (--i);}
}