單片機(jī)課程設(shè)計(jì)倒計(jì)時(shí)秒表-資料下載頁
2025-06-30 18:46本頁面
【正文】 C:INC 23H 。23H為設(shè)定值十位緩存MOV A,23HCJNE A,10,K5MOV 23H,0AJMP K5SLINC:INC 22H 。22H為設(shè)定值個(gè)位緩存MOV A,22HCJNE A,10,K6MOV 22H,0AJMP K5ALARM:JB 7FH,ALARM0 。7FH為時(shí)間到標(biāo)志，RAM內(nèi)存2FH的D7位AJMP ALARMRT 。時(shí)間未到，跳出報(bào)警ALARM0:CPL ACALL DISP 。利用顯示子程序延時(shí)約2ms求反，產(chǎn)生250H的方波。AJMP ALARMALARMRT:RETT0INT: MOV TH0,03CH。 。定時(shí)中斷子程序。重裝定時(shí)常數(shù)MOV TL0,0B0H。DJNZ R0,T0INTR 。50msX20=1S，未滿20次，跳出中斷子程序MOV R0,20JNB 7FH,T0INT00 。時(shí)間未到轉(zhuǎn)T0INT00DJNZ R3,T0INTR 。未到3 S 跳出中斷子程序CLR 7FH 。3 S時(shí)間到，清計(jì)時(shí)時(shí)間到標(biāo)志CLR TR0 。關(guān)定時(shí)器AJMP T0INTR 。跳出中斷T0INT00:JNB 7EH,T0INT0 。7EH為倒計(jì)時(shí)標(biāo)志，1為倒計(jì)時(shí)DEC R4 。＝1,R4－1CJNE R4,0,T0INTR CLR 7EH SETB 7FH 。時(shí)間到標(biāo)志AJMP T0INTRT0INT0:INC R4CJNE R4,99,T0INTRSETB 7FH 。時(shí)間到標(biāo)志T0INTR:RETI DISP: JNB 7DH,DISP1MOV 20H,22H 。22H存設(shè)定個(gè)位MOV 21H,23H 。23H存設(shè)定十位MOV A,23H MOV B,10MUL ABADD A,22HMOV R4,ADISP1:MOV A,R4MOV B,10DIV AB 。當(dāng)前值除以10MOV 20H,A 。得出的商送給十位MOV 21H,B 。得出的余數(shù)送給個(gè)位 MOV A,20H 。十位顯示MOVC A,@A+DPTRMOV P0,ASETB LCALL DELAYCLR MOV A,21H 。個(gè)位顯示MOVC A,@A+DPTRMOV P0,ASETB LCALL DELAYCLR RETDELAY: 。誤差 0usMOV R6,10DL0:MOV R5,50DJNZ R5,$DJNZ R6,DL0RETTAB: DB 0C0H,0F9H,0A4H,0B0H,99H 。共陽極09顯示代碼DB 92H,82H,0F8H,80H,90H END13
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