原理图:源程序:/＊*＊*＊＊＊＊＊＊＊＊*＊**＊＊＊＊＊＊*＊＊*＊＊＊＊*＊＊＊***＊＊＊＊＊＊**＊＊*****＊＊＊*＊＊＊＊*标题：ﻩ定时器中断精确到00、0１得秒表效果:能清零重新开始，暂停,继续计时,能精确到０、０1秒作者：皖绩小挺说明：ﻩ使用１2M晶振，四位数码管，3个按键***＊＊＊*＊＊*＊＊****＊****＊＊＊*＊*****＊＊＊＊*＊**＊＊＊＊**＊＊*＊*＊*＊*＊**＊＊*＊＊*＊/＃ｉncｌude〈ｒｅg52、h〉#ｄefineｕintunｓignｅｄint#ｄｅfｉnｅucｈａruｎｓigｎeｄcharuｉnttemp,ｔt,qian，bai，sｈi，ge；ｓbitsmｇ＿q=P1＾0;sbiｔsｍg＿b=P1^1;sbitsｍｇ_s=Ｐ１^２；sbitsmg_ｇ=P1^３;sbitkｅｙ1=P3^７；ﻩsbｉtkey2＝Ｐ3^6；sbitｋey3＝P３＾5;ucharｃoｄetable[]={０xc０，０ｘf９，0xa４,0ｘb0,0x９9,ﻩﻩ0x9２，0ｘ82，0xf８，0x80，0x9０｝；uｃｈarｃoｄetａble1［］={0x４０,０x７9,0x24，0x３0，0x19,ﻩ0ｘ12,0ｘ0２,0x７８，0x０0,0ｘ10}；／/带小数点voidｋeyscａｎ(）；ｖｏｉdｄisplay（uｉntｓhｉ，uｉntge）；voiｄｄelay（ｕintz）;ｖｏidｉniｔ(）;/＊***＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊*＊＊＊＊***＊*＊＊＊*＊＊＊***＊＊**＊＊*＊＊＊**＊**＊*＊*主函数＊＊＊＊＊＊＊*＊*＊*＊＊＊＊*＊＊＊***＊＊*＊＊**＊**＊＊*＊＊＊＊＊＊＊＊＊＊*＊＊＊＊*＊＊＊＊*＊＊＊***＊*＊／voidmain(）｛ﻩinit（）；／/初始化子程序wｈile（1）ﻩ｛ﻩiｆ（tt＝=1）ﻩ｛ﻩﻩﻩtt＝０;ﻩtemp＋+;ﻩﻩiｆ(ｔemｐ==１000０){ﻩﻩtｅmp=0;ﻩﻩ｝ﻩｑiaｎ=tｅmp/1000;ﻩbai=ｔeｍｐ%１000/１00；ﻩshi=teｍp%１0０/1０;ﻩｇe=temｐ%１0；ﻩﻩ｝keｙscaｎ（)；ﻩdiｓpｌａy（shi,ge）;}}／＊＊*＊＊*＊＊＊＊＊**＊****＊**＊*＊＊*＊＊**＊＊＊*＊＊＊*＊*＊*＊*＊**＊**＊＊＊＊***＊＊*＊＊＊＊*＊＊*＊ﻩﻩﻩ延时****＊＊＊***＊＊＊**＊***＊***＊＊＊*＊＊＊＊＊*＊****＊＊＊＊*＊*＊＊＊＊****＊＊*＊*＊＊*＊**＊＊＊＊*＊*/voiｄdelay（ｕinｔz）{ﻩuｉntx，ｙ;ﻩfor(x=ｚ；x>０；x－—）ﻩﻩfor（y=110;ｙ>０;ｙ－-);}/**＊＊**＊＊＊＊*＊*＊**＊**＊＊＊***＊＊＊*＊＊*＊＊＊＊＊＊＊****＊＊＊*＊*＊＊***＊*＊**＊＊***＊＊*＊＊ﻩ按键控制**＊＊**＊*＊＊＊＊＊＊＊＊＊＊＊**＊*＊＊*＊*＊＊＊＊＊＊****＊＊＊＊***＊*＊*＊＊＊**＊**＊**＊**＊*＊*＊*＊*/ｖｏiｄｋｅyscan（）{ﻩif(key１＝＝0)／／清零并重新开始计时{ﻩｔemp＝0;ﻩＴＲ0＝1；ﻩ｝ﻩｉf(ｋey2==0)／/暂停计时ﻩ{TR0=０;｝ｉf(key3=＝0）/／继续计时{ﻩTR0=1;｝}/＊＊*＊＊＊*＊*＊*＊＊＊*＊＊***＊***＊*＊*＊＊＊＊＊*＊****＊＊＊**＊*＊**＊*＊＊＊**＊＊＊*＊**＊*＊***显示＊＊*＊＊***＊*＊＊*＊**＊＊**＊*＊＊*＊＊*＊＊＊＊*＊*＊＊＊＊＊*＊＊＊＊***＊**＊*＊＊＊＊**＊＊***＊＊*＊*＊＊/voidｄisplay(ｕinｔshi,ｕintｇe)｛ｓｍｇ_q＝0;P０=taｂle［qｉan]；ﻩﻩdelay(１）；ﻩﻩｓmg＿ｑ＝１;ﻩP0=0xff；ﻩﻩsｍｇ_ｂ=0;ﻩＰ０=tａｂle１［ｂaｉ]；ﻩﻩｄelay（１）；ｓｍｇ_ｂ＝1;P0=0ｘｆf；ﻩﻩsmg_s=0；ﻩP0=tablｅ［shi];ﻩdelａy(1）；ﻩsmg_ｓ=1；ﻩＰ0=0xff;ﻩsmg＿g=0;ﻩﻩP0=ｔaｂle[ｇe］；dｅlaｙ(１）；ﻩsmｇ_g=1；P0=0xff;}/*＊*＊＊＊＊*****＊*＊＊＊***＊＊*