16键计算器 c51实现

开辟一显示缓冲区，显示中断程序定时读取缓冲区显示各灯位，每灯位显示2.5ms，显示4只灯需要10ms,也就是显示的刷新频率是100Hz，亮度为25%。这样既保证亮度又不闪烁，同时CPU还有足够时间做其他事情。

2、键盘中断扫描

利用键盘中断扫描程序，读出按键的键码，存入键盘缓冲区，供主程序读区。

3、计算器的主程序读取键盘缓冲区的键码，驱动计算器的运行，计算器的运行过程要清晰明了；

4、计算中需要十进制与十六进制（或二进制）转化。

#define LED_seg      XBYTE[0x6000]     //段码地址#define LED_light    XBYTE[0x8000]      //灯位地址#include "reg51.h"#include "absacc.h"unsigned char read_key(unsigned char);unsigned char display(unsigned char,unsigned char);void delay(unsigned int);unsigned char light[4]={0xfe,0xfd,0xfb,0xf7};   //扫描值 灯位码unsigned char seg[16]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71}; //段码unsigned char disp_buffer[5]={1,0,0,0,0};            //当前灯位、 显示区unsigned char key_buffer[2]={0,0xff};           //缓冲区满标志、键码void main(){Unsigned char temp[5];unsigned char i;unsigned char operator=0;unsigned int tempa,tempb;bit first=1;TMOD=0x01;       //置T0为方式1TL0=0x0;          //延时2.5mS的定时器初始值TH0=0xf7;          //赋初值PT0=1;             //定时中断0优先设置TR0=1;           //启动定时ET0=1;           //允许定时IT1=0;        //电平触发低电平有效EX1=1;       //允许外中断PX1=1;       // 外部中断1优先级设定EA=1;        //中断总允许while(1){P1=0xf0;                           //扫描if (key_buffer[0]){switch(key_buffer[1])              //缓冲区满{case 0:case 1:case 2:case 3:case 4:case 5:case 6:case 7:case 8:case 9: if (first)  for(i=1;i<=4;i++)   //保存数据，等待另一个数据输入{temp[i]=disp_buffer[i];disp_buffer[i]=0;                                           }first=0;for(i=1;i<=3;i++)  disp_buffer[i]=disp_buffer[i+1];disp_buffer[4]=key_buffer[1];break;case 10:case 11:case 12:case 13:case 14: first=1;tempa=1000*disp_buffer[1]+100*disp_buffer[2]+10*disp_buffer[3]+disp_buffer[4];tempb=1000*temp[1]+100*temp[2]+10*temp[3]+temp[4];switch(operator){case 10:tempa+=tempb;break;case 11:tempa=tempb-tempa;break;case 12:tempa*=tempb;break;case 13:tempa=tempb/tempa;}tempa%=10000;disp_buffer[1]=tempa/1000;tempa%=1000;disp_buffer[2]=tempa/100;tempa%=100;disp_buffer[3]=tempa/10;disp_buffer[4]=tempa%10;operator=key_buffer[1];break;case 15: for(i=1;i<=4;i++)  disp_buffer[i]=temp[i]=0;first=1;operator=0;}key_buffer[0]=0;                     //缓冲区空}          }}void disp_LED() interrupt 1{TL0=0x0;         //延时2.5mS的定时器初始值TH0=0xf7;if (disp_buffer[0]==5)  disp_buffer[0]=1;display(disp_buffer[disp_buffer[0]],disp_buffer[0]);disp_buffer[0]++;}void get_keypad_code() interrupt 2{unsigned char i,key;EA=0;for (i=0;i<=3;i++){key=read_key(light[i]);    //读键码if (key!=0xff) delay(10);                //延时5-10ms,去抖动if (read_key(light[i])!=key) key=0xff;    //读键码比较if (key!=0xff){key_buffer[0]=1;                //缓冲区满key_buffer[1]=key;      //键码}                     }EA=1;}unsigned char read_key(unsigned char scan){P1=scan;       //扫描switch(P1)     //返回扫描码->键码{case 0x77:return(0x7);case 0xb7:return(0x8);case 0xd7:return(0x9);case 0xe7:return(0xd);case 0x7b:return(0x4);case 0xbb:return(0x5);case 0xdb:return(0x6);case 0xeb:return(0xc);case 0x7d:return(0x1);case 0xbd:return(0x2);case 0xdd:return(0x3);case 0xed:return(0xb);case 0x7e:return(0xf);case 0xbe:return(0x0);case 0xde:return(0xe);case 0xee:return(0xa);default:  return(0xff);}}unsigned char display(unsigned char disp_key,unsigned char n) //disp_key 显示字符,n 灯位{if ((n<=4)&&(n>=1)) LED_light=light[n-1];else  LED_light=0xff;if ((disp_key>=0)&&(disp_key<=16)) LED_seg=seg[disp_key];else  LED_seg=0x00;return light[n-1];}void delay(unsigned int k)     //延时k*1ms{unsigned int i,j;for (j=0;j<=k;j++)for(i=0;i<=1085;i++);}