二、方案论证
我们在这里选用了C8051F单片机，它是完全集成的混合信号系统级芯片（SoC），具有与8051兼容的高速CIP-51内核，与MCS-51指令集完全兼容，片内集成了数据采集和控制系统中常用的模拟、数字外设及其他功能部件；内置FLASH程序存储器、内部RAM，大部分器件内部还有位于外部数据存储器空间的RAM，即XRAM。C8051F单片机具有片内调试电路，通过4脚的JTAG接口可以进行非侵入式、全速的在系统调试。

三、 系统硬件电路设计
该系统分为两个部分，主控电路和扫描电路，其中键盘扫描和LED扫描为今后节省I/O口线，我将键盘的扫描和LED的扫描共用，在扫描LED的同时也扫描键盘，这样不但方便，而且为今后的扩展留下了相当大的余地。
3.1主控制器
单片机使用c8051f310，并且使用它的开发板易于烧录，改变程序和外围电路。
3.2显示电路
显示板因为常用，是我自己画出来交给工厂做的，采用4个两位共阳数码管，从P0口输出，8位段码分别和P0相接，通过定时器实现秒钟的加一，又因为310有推挽输出，所以不必再加外部电路对数码管进行驱动，直接将它们与P0口相连就可以
3.3键盘电路
键盘是是与数码管的位选相连，通过二极管使它们具有单向性，同时将开头最终通过三极管接单片机的P3.4，只要有按键按下，P3.4就一定会发生变化，通过这个变化在去扫描位就可以得出是哪个按键了。
附电路图：

四、系统程序设计
系统和程序主要包括：显示程序，键盘扫描程序，自动加秒，分，时，日，月，年，
附程序：

#include "c8051f310.h"
#define uchar unsigned char
#define unchar unsigned char
uchar code duan[10] ={0xa0,0xbd,0x26,0x2c,0x39,0x68,0x60,0xad,0x20,0x28};
//段码表 0 1 2 3 4 5 6 7 8 9
uchar code wei[8]={0x02,0x01,0x08,0x04,0x20,0x10,0x80,0x40};//位码表
uchar code week1[7]={0xbd,0x26,0x2c,0x39,0x68,0x60,0xad} ;//星期一到星期日
uchar dataa,sec,min,hour,ymd,year,year1=9,year2=20,month=8，day=22,week=6;//初始值是7-00:00:00,日期是2009-08-22；
uchar n,cnt,sw1=0,sw2,sw3,cnt1,sw5;
uchar key1,key2,key3,key4=0,key5=0;
sbit P3_4=P3^4;
void scan_key(void);
void delay(ms);

void init(void)
{
IE =0x8A;
TCON =0x50;
TMOD =0x11;
IP =0x0A;
TH0 =(65536-1270)/256;
TL0 =(65536-1270)%256;
TH1 =(65536-500)/256;
TL1 =(65536-500)%256;
}

void time0(void) interrupt 1
{
TH0 =(65536-1270)/256;
TL0 =(65536-1270)%256;
dataa++;
if(sw1!=0&&key4==0) //第一个按键按下，且第四个没有按下
{
if(++cnt1==40)
{
cnt=0;
if(sw5==0&&sw1==1)
{
for(n=0;n<20;n++)
{
P1 =0x00;
P1 =P1&0xf3; //闪烁程序
P0 =duan[sec%10];
P1 =wei[0];
delay(8);
P1 =0x00;
P0 =duan[sec/10];
P1 =wei[1];
delay(8);
P1 =0x00;
P0 =duan[hour%10];
P1 =wei[4];
delay(8);
P1 =0x00;
P0 =duan[hour/10];
P1 =wei[5];
delay(8);
P1=0x00;
P0 =0x7f;
P1 =wei[6];
delay(8);
P1=0x00;
P0 =week1[week];
P1 =wei[7];
delay(8);
}
scan_key();
}
if(sw5==0&&sw1==2)
{
for(n=0;n<20;n++)
{
P1 =0x00;
P1 =P1&0xcf;
P0 =duan[sec%10];
P1 =wei[0];
delay(8);
P1 =0x00;
P0 =duan[sec/10];
P1 =wei[1];
delay(8);
P1 =0x00;
P0 =duan[min%10];
P1 =wei[2];
delay(8);
P1 =0x00;
P0 =duan[min/10];
P1 =wei[3];
delay(8);
P1 =0x00;
P0 =0x7f;
P1 =wei[6];
delay(8);
P1 =0x00;
P0 =week1[week];
P1 =wei[7];
delay(8);
}
scan_key();
}
if(sw5==0&&sw1==3)
{
for(n=0;n<20;n++)
{
P1 =0x00;
P1 =P1&0x7f;
P0 =duan[sec%10];
P1 =wei[0];
delay(8);
P1 =0x00;
P0 =duan[sec/10];
P1 =wei[1];
delay(8);
P1 =0x00;
P0 =duan[min%10];
P1 =wei[2];
delay(8);
P1 =0x00;
P0 =duan[min/10];
P1 =wei[3];
delay(8);
P1=0x00;
P0=duan[hour%10];
P1=wei[4];
delay(8);
P1 =0x00;
P0 =duan[hour/10];
P1 =wei[5];
delay(8);
P1 =0x00;
P0 =0x7f;
P1 =wei[6];
delay(8);
}
scan_key();
}
if(sw5==1&&sw1==9)
{
for(n=0;n<20;n++)
{
P1 =0x00;
P1 =P1&0x3f;
P0 =duan[month%10];
P1 =wei[2];
delay(8);
P1 =0x00;
P0 =duan[month/10];
P1 =wei[3];
delay(8);
P1 =0x00;
P0 =duan[year1%10];
P1 =wei[4];
delay(8);
P1 =0x00;
P0 =duan[year1/10];
P1 =wei[5];
delay(8);
P1 =0x00;
P0 =duan[year2%10];
P1 =wei[6];
delay(8);
P1 =0x00;
P0 =duan[year2/10];
P1 =wei[7];
delay(8);
}
scan_key();
}
if(sw5==1&&sw1==8)
{
for(n=0;n<20;n++)
{
P1 =0x00;
P1 =P1&0xf3;
P0 =duan[day%10];
P1 =wei[0];
delay(8);
P1 =0x00;
P0 =duan[day/10];
P1 =wei[1];
delay(8);
P1 =0x00;
P0 =duan[year1%10];
P1 =wei[4];
delay(8);
P1 =0x00;
P0 =duan[year1/10];
P1 =wei[5];
delay(8);
P1 =0x00;
P0 =duan[year2%10];
P1 =wei[6];
delay(8);
P1 =0x00;
P0 =duan[year2/10];
P1 =wei[7];
delay(8);
}
scan_key();
}
if(sw5==1&&sw1==7)
{
for(n=0;n<20;n++)
{
P1 =0x00;
P1 =P1&0xc3;
P0 =duan[day%10];
P1 =wei[0];
delay(8);
P1 =0x00;
P0 =duan[day/10];
P1 =wei[1];
delay(8);
P1 =0x00;
P0 =duan[month%10];
P1 =wei[2];
delay(8);
P1 =0x00;
P0 =duan[month/10];
P1 =wei[3];
delay(8);
P1 =0x00;
P0 =duan[year2%10];
P1 =wei[6];
delay(8);
P1 =0x00;
P0 =duan[year2/10];
P1 =wei[7];
delay(8);
}
scan_key();
}
if(sw5==1&&sw1==6)
{
for(n=0;n<20;n++)
{
P1 =0x00;
P1 =P1&0xc3;
P0 =duan[day%10];
P1 =wei[0];
delay(8);
P1 =0x00;
P0 =duan[day/10];
P1 =wei[1];
delay(8);
P1 =0x00;
P0 =duan[month%10];
P1 =wei[2];
delay(8);
P1 =0x00;
P0 =duan[month/10];
P1 =wei[3];
delay(8);
P1 =0x00;
P0 =duan[year1%10];
P1 =wei[4];
delay(8);
P1 =0x00;
P0 =duan[year1/10];
P1 =wei[5];
delay(8);
}
scan_key();
}
}

}
}

void time1(void) interrupt 3
{
TH1 =(65536-500)/256;
TL1 =(65536-500)%256;
if(++cnt>8) cnt=0;
if(sw5==0) //显示时分秒
{switch(cnt)
{
case 0: P1 =0x00;
P0 =duan[sec%10];
P1 =wei[cnt]; break;
case 1: P1 =0x00;
P0 =duan[sec/10];
P1 =wei[cnt];break;
case 2: P1 =0x00;
P0 =duan[min%10];
P1 =wei[cnt]; break;
case 3: P1 =0x00;
P0 =duan[min/10];
P1 =wei[cnt];
scan_key(); break;
case 4: P1 =0x00;
P0 =duan[hour%10];
P1 =wei[cnt];
scan_key();break;
case 5: P1 =0x00;
P0 =duan[hour/10];
P1 =wei[cnt];
scan_key();break;
case 6: P1 =0x00;
P0 =0x7f;
P1 =wei[cnt];
scan_key(); break;
case 7: P1 =0x00;
P0 =week1[week];
P1 =wei[cnt];
scan_key();break;
default: break;
}
}
if(sw5==1) //显示年月日
{switch(cnt)
{
case 0: P1 =0x00;
P0 =duan[day%10];
P1 =wei[cnt]; break;
case 1: P1 =0x00;
P0 =duan[day/10];
P1 =wei[cnt];break;
case 2: P1 =0x00;
P0 =duan[month%10];
P1 =wei[cnt]; break;
case 3: P1 =0x00;
P0 =duan[month/10];
P1 =wei[cnt];
scan_key(); break;
case 4: P1 =0x00;
P0 =duan[year1%10];
P1 =wei[cnt];
scan_key();break;
case 5: P1 =0x00;
P0 =duan[year1/10];
P1 =wei[cnt];
scan_key();break;
case 6: P1 =0x00;
P0 =duan[year2%10];
P1 =wei[cnt];
scan_key(); break;
case 7: P1 =0x00;
P0 =duan[year2/10];
P1 =wei[cnt];
scan_key();break;
default: break;
}
}
}

void conv(void)
{
if(dataa>=201)
{dataa=0;sec++;}
if(sec>=60)
{sec=0;min++;}
if(sw1==0&&min>=60)
{min=0;hour++;}
if(sw1==0&&hour>=24)
{
if(year%4==0)
{
if(month==2)
{
if(day==29)
{
day =1;
month++;
}
else day++;
}
else
{
if(month==4||month==6||month==9||month==11)
{
if(day==30)
{
day =1;
month++;
}
else day++;
}
else
{
if(day==31)
{
day =1;
month++;
if(month==13)
{
month =1;
year++;
}
}
else day++;
}
}
}