【正文】 13．—應(yīng)用與設(shè)計(jì)。定時(shí)器T0中斷子程序 MOV TH0,03CH MOV A,24H JZ LOOP0 DJNZ 24H,LOOP0 CLR LOOP0: MOV A,26H JZ LOOP1 DJNZ 26H,LOOP1 CLR LOOP1: MOV A,27H JZ LOOP2 DJNZ 27H,LOOP2 SETB MOV 30H,0 MOV 31H,0 MOV 28H,30LOOP2: MOV A,28H JZ LOOP3 DJNZ 28H,LOOP3 CLR LOOP3: MOV A,25H JZ LOOP4 MOV B,5 DIV AB MOV A,B JNZ LOOP5 CPL LOOP5: DEC 25HLOOP4: RETISERVE1: MOV TL1,0B0H 。8. DB 0EFH。6. DB 087H。4. DB 0EDH。2. DB 0CFH。0. DB 086H。9 DB 077H。7 DB 07FH。5 DB 07DH。3 DB 066H。1 DB 05BH。20ms延時(shí)程序 MOV R4,250 DJNZ R4,$ DJNZ R5,$4 RETTAB0: DB 03FH。顯示總金額個(gè)位 MOVC A,A+DPTR CPL A MOV DPTR,0FF22H MOVX DPTR,A AJMP FLAGFLAG4: MOV DPTR,0FF21H MOV A,1 MOVX DPTR,A MOV DPTR,TAB0 MOV A,31H 。顯示牛奶剩余量 MOVC A,A+DPTR CPL A MOV DPTR,0FF22H MOVX DPTR,A AJMP FLAGFLAG2: CJNE A,3,FLAG3 MOV DPTR,0FF21H MOV A,4 MOVX DPTR,A MOV DPTR,TAB0 MOV A,R1 。顯示可樂(lè)剩余量 MOVC A,A+DPTR CPL A MOV DPTR,0FF22H MOVX DPTR,A AJMP FLAGFLAG0: CJNE A,1,FLAG1 MOV DPTR,0FF21H MOV A,10H MOVX DPTR,A MOV DPTR,TAB0 MOV A,21H 。DPTR指向8155控制寄存器端口 MOVX DPTR,A ?？偨痤~顯示程序 MOV B,10 DIV AB MOV R1,A MOV R2,B MOV A,3 。退幣指示燈初始化 MOV P1,0FFH 。無(wú)貨指示燈初始化 CLR 。退幣指示燈亮的計(jì)時(shí)長(zhǎng)度初始化 CLR 。取物指示燈亮的計(jì)時(shí)長(zhǎng)度初始化 MOV 27H,0 。投幣不足時(shí)指示燈亮的計(jì)時(shí)長(zhǎng)度初始化 MOV 25H,0 。總金額元位初始化 MOV 31H,0 。純水初始數(shù)量 MOV 22H,0 。啟動(dòng)定時(shí)器T1 MOV 20H,0 。允許CPU中斷 SETB TR0 。允許T0中斷 SETB ET1 。裝入T1計(jì)數(shù)值低8位 MOV TH1,0FCH 。裝入T0計(jì)數(shù)值低8位 MOV TH0,03CH 。購(gòu)買牛奶 JB ,KEY5 JNB ,$ LCALL D20MS MOV 27H,100 MOV A,22H JZ EMPTY5 MOV A,30H CJNE A,3,CMP5CMP5: JC LACK5 SUBB A,3 MOV 30H,A DEC 22H CLR MOV 25H,0 CLR SETB MOV 26H,30 LJMP KEY5LACK5: SETB MOV 25H,0 CLR CLR MOV 24H,30 LJMP KEY5EMPTY5: CLR MOV 25H,30 CLR CLR KEY5: LJMP KEYROUT6: LCALL D20MS JB ,KEY6 JNB ,$ LCALL D20MS SETB CLR MOV 25H,0 CLR CLR MOV 27H,0 MOV 28H,30 MOV 30H,0 MOV 31H,0KEY6: LJMP KEYINITIAL:MOV TMOD,11H 。熄滅取物指示燈KEY3: LJMP KEYROUT4: LCALL D20MS 。 CLR 。投幣不足指示燈延時(shí)3s熄滅 LJMP KEY3EMPTY3: CLR 。熄滅無(wú)貨指示燈 CLR 。取物指示燈延時(shí)3s熄滅 LJMP KEY3LACK3: SETB 。熄滅無(wú)貨指示燈 SETB ?？蓸?lè)數(shù)量減1 CLR 。角位為0時(shí)，則向元位借1元， 角位則為5，元位自減1元 MOV 31H,5 CJ3: MOV A,30H SUBB A,2 。元位小于2，則跳轉(zhuǎn)，即投幣不足LP3: MOV A,31H JZ FG3 MOV 31H,0 ?？偨痤~元位為2，則跳轉(zhuǎn) MOV A,31H 。判斷可樂(lè)是否有貨，無(wú)貨則跳轉(zhuǎn) MOV A,30H 。購(gòu)買可樂(lè) JB ,KEY3 JNB ,$ LCALL D20MS MOV 27H,100 ?？偨痤~寄存保護(hù) MOV 33H,31H MOV 27H,100 CLR MOV A,30H ADD A,5 ?？偨痤~元位加1KEY1: MOV A,30H CJNE A,100,NEXT3NEXT4: MOV 30H,32H MOV 31H,33H SETB MOV 28H,30 AJMP NEXT5NEXT3: JNC NEXT4NEXT5: LJMP KEYROUT2: LCALL D20MS 。投1元 JB ,KEY1 JNB ,$ LCALL D20MS MOV 32H,30H 。總金額角位加5 CJNE A,10,CMP0 MOV A,0 。設(shè)置退幣指示燈延時(shí)10s亮開(kāi)始 計(jì)時(shí) CLR 。投5角 JB