簡易數(shù)字萬用表設計-資料下載頁
2025-06-30 23:36本頁面
【正文】 DELAY_5ms3: djnz R7,DELAY_5ms3 。延時時間為 Time=( ( (R7*2)+2+1 )*R6+2+1 )*R5+1 djnz R6,DELAY_5ms2 。 djnz R5,DELAY_5ms1 。 ret SEGMENT7: DB 3Fh 。7段數(shù)碼管字符0的abcdefg的值,a在最低位,最高位始終保留為0 DB 06h DB 5Bh DB 4Fh DB 66h DB 6Dh DB 7Dh DB 07h DB 7Fh DB 6Fh DISPLAY: mov DPTR,0fEffh 。寫第一位數(shù)碼管 mov r1,40h mov A,@r1 movx @DPTR,A setb C mov ,C clr C mov ,C call DELAY_5ms setb C mov ,C inc r1 mov A,@r1 。寫第二位數(shù)碼管 movx @DPTR,A setb C mov ,C clr C mov ,C call DELAY_5ms setb C mov ,C inc r1 mov A,@r1 。寫第三位數(shù)碼管 movx @DPTR,A setb C mov ,C clr C mov ,C call DELAY_5ms setb C mov ,C inc r1 mov A,@r1 。寫第四位數(shù)碼管 movx @DPTR,A setb C mov ,C clr C mov ,C call DELAY_5ms setb C mov ,C ret 。雙字節(jié)二進制無符號數(shù)乘法。被乘數(shù)在R2(高位)、R3(低位)中，乘數(shù)在R6(高位)、R7(低位)中。乘積在R2(高位)、RRR5(低位)中。用到累加器A,B,PSW,R2~R7。永遠不會產(chǎn)生進位。在出口時總是清除C。若結果超出2個字節(jié)范圍則OV=1。MULD2: MOV A,R3 MOV B,R7 MUL AB MOV R4,B MOV R5,A MOV A,R3 MOV B,R6 MUL AB ADD A,R4 MOV R4,A CLR A ADDC A,B MOV R3,A MOV A,R2 MOV B,R7 MUL AB ADD A,R4 MOV R4,A MOV A,R3 ADDC A,B MOV R3,A CLR A RLC A XCH A,R2 MOV B,R6 MUL AB ADD A,R3 MOV R3,A MOV A,R2 ADDC A,B MOV R2,A ORL A,R3 JZ MULD21 SETB OV RETMULD21: CLR OV RET 。四字節(jié)無符號數(shù)除法。R0存放被除數(shù),除數(shù),商數(shù)的地址。從R0開始的連續(xù)四個字節(jié)為結果的余數(shù),入口時可以為任意，但在出口時發(fā)生變化。其后的連續(xù)4個字節(jié)在入口時是被除數(shù),出口時是商數(shù)。再其后的連續(xù)四個字節(jié)在入口時是除數(shù),出口時保持不變。用到累加器A,B,PSW,R0~R7。如果除數(shù)為零，則置OV=1標志，否則清零。在出口時總是清除C。DIVD4: MOV A,R0 MOV B,A ADD A,08h MOV R1,A MOV A,00h ORL A,@R1 INC R1 ORL A,@R1 INC R1 ORL A,@R1 INC R1 ORL A,@R1 JZ DIVD45 MOV R1,B MOV R2,04hDIVD41: MOV @R1,00h INC R1 DJNZ R2,DIVD41 MOV R3,20hDIVD42: MOV R2,08h MOV A,B MOV R0,A ADD A,07h MOV R1,A CLR CDIVD43: MOV A,@R1 RLC A MOV @R1,A DEC R1 DJNZ R2,DIVD43 MOV A,R0 ADD A,03h MOV R1,A MOV A,R0 ADD A,0Bh MOV R0,A MOV A,@R1 SUBB A,@R0 MOV R4,A DEC R1 DEC R0 MOV A,@R1 SUBB A,@R0 MOV R5,A DEC R1 DEC R0 MOV A,@R1 SUBB A,@R0 MOV R6,A DEC R1 DEC R0 MOV A,@R1 SUBB A,@R0 MOV R7,A JC DIVD44 MOV A,B MOV R0,A ADD A,03h MOV R1,A MOV A,R4 MOV @R1,A DEC R1 MOV A,R5 MOV @R1,A DEC R1 MOV A,R6 MOV @R1,A DEC R1 MOV A,R7 MOV @R1,A MOV A,R0 ADD A,07h MOV R1,A INC @R1DIVD44: DJNZ R3,DIVD42 MOV R0,B CLR OV CLR C RETDIVD45: SETB OV CLR C RET
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