【正文】
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 RETdelay_250: push psw push 07h mov r7,0ffhdelay_250_1: nop nop nop nop djnz r7,delay_250_1 pop 07h pop psw ret END 附錄2:(電路原理圖)以下內(nèi)容與本文檔無關(guān)!??!以下內(nèi)容與本文檔無關(guān)!?。?。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四字節(jié)/兩字節(jié)無符號數(shù)除法程序 。* 兩字節(jié)無符號數(shù)乘法程序 。次次高位為0,先看次高位是否為不亮 SUBB A,0AH JNZ JJ2 MOV 42H,0AH 。次高位為0,先看最高位是否為不亮 SUBB A,0AH JNZ JJ1 MOV 41H,0AH 。***************************work: 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 JJ0 MOV 40H,0AH 。***************************。 延 時 程 序 *。G RR A MOV R5,A AJMP PLAY ENDOUT: MOV P2,0FFH MOV P0,0FFH RET TAB: DB 18h, 7Bh, 2Ch, 29h, 4Bh, 89h, 88h, 3Bh, 08h, 09h,0ffh 。G MOV R5,7fH。接收成功標志pint0_exit: RETI 顯 示 程 序 。將計數(shù)值移入處理單元 MOV 45H,TH0 。 CLR EX0 。外中斷0,收到回波時進入PINT0: nop jb ,pint0_exit CLR TR0 。延時,避開發(fā)射的直達聲波信號 SETB EX0 。40KHZ nop nop nop