超聲波測距儀的畢業設計-資料下載頁

　　

【正文】 次 CLR TR0 MOV TH0,00H MOV TL0,00H SETB ET1 SETB EA SETB TR0 。啟動計數器T0，用以計算超聲來回時間 SETB TR1 。開啟發超聲波用定時器T1OUT: RETIINTT1: CPL VOUT 。T1中斷，發超聲波用 DJNZ R4,RETIOUT CLR TR1 。超聲波發送完畢，關T1 CLR ET1 MOV R4,04H SETB EX0 。開啟接收回波中斷RETIOUT: RETIPINT0: CLR TR0 。外中斷0，收到回波時進入，關計數器 CLR TR1 CLR ET1 CLR EA CLR EX0 MOV 44H,TL0 。將計數值移入處理單元 MOV 45H,TH0 SETB 00H 。接收成功標志 RETI*************延時程序*************DL1MS: MOV R6,14HDL: MOV R7,19HDL1: DJNZ R7,DL1 DJNZ R6,DL RET ************距離計算程序（距離=計數值17／1000cm **********************MATH: PUSH ACC PUSH PSW PUSH B MOV PSW,18H MOV R3,45H MOV R2,44H MOV R1,00D MOV R0,17D LCALL MUL2BY2 MOV R3,03H MOV R2,0E8H LCALL DIV4BY2 LCALL DIV4BY2 MOV 40H,R4 MOV A,40H JNZ J0 MOV 40H,0AH 。最高位為0，不點亮J0: MOV A,R0 MOV R4,A MOV A,R1 MOV R5,A MOV R3,00D MOV R2,100D LCALL DIV4BY2 MOV 41H,R4 MOV A,41H JNZ J1 MOV A,40H 。次高位為0，先看最高位是否為不亮 SUBB A, 0AH JNZ J1 MOV 41H,0AH。 ；最高位不亮，次高位也不亮J1: MOV A, R0 MOV R4, A MOV A, R1 MOV R5, A MOV R3, 00D MOV R2, 10D LCALL DIV4BY2 MOV 42H, R4 MOV A, 42H JNZ J2 MOV A,41H。 ；次次高位為0，先看次高位是否為不亮 SUBB A, 0AH JNZ J2 MOV 42H,0AH。 ；次高位不亮，次次高位也不亮J2: MOV 43H, R0 POP B POP PSW POP ACC RET*******************************2字節無符號數乘法程序**************************MUL2BY2: CLR A MOV R7, A MOV R6, A MOV R5, A MOV R4, A MOV 46H, 10HMULLOOP1: CLR C MOV A, R4 RLC A MOV R4, A MOV A, R5 RLC A MOV R5, A MOV A, R6 RLC A MOV R6, A MOV A, R7 RLC A MOV R7, A MOV A, R0 RLC A MOV R0, A MOV A, R1 RLC A MOV R1, A JNC MULLOOP2 MOV A, R4 ADD A, R2 MOV R4, A MOV A, R5 ADDC A, R3 MOV R5, A MOV A, R6 ADDC A, 00H MOV R6, A MOV A, R7 ADDC A, 00H MOV R7, AMULLOOP2: DJNZ 46H, MULLOOP1 RET****************************4字節／2字節無符號數除發程序***********************DIV4BY2: MOV 46H, 20H MOV R0, 00H MOV R1, 00HDIVLOOP1: MOV A, R4 RLC A MOV R4, A MOV A, R5 RLC A MOV R5, A MOV A, R6 RLC A MOV R6, A MOV A, R7 RLC A MOV R7, A MOV A, R0 RLC A MOV R0, A MOV A, R1 RLC A MOV R1, A CLR C MOV A, R0 SUBB A, R2 MOV B, A MOV A, R1 SUBB A, R3 JC DIVLOOP2 MOV R0, B MOV R1, ADIVLOOP2: CPL C DJNZ 46H, DIVLOOP1 MOV A, R4 RLC A MOV R4, A MOV A, R5 RLC A MOV R5, A MOV A, R6 RLC A MOV R6, A MOV A, R7 RLC A MOV R7, A RET END。 ；程序結束