MOV
TH000H
MOV
TL000H
SETB
ET1
SETB
EA
SETB
TR0
时间
SETB
TR1
OUT
RETI
；T1中断，发超声波用
INTT1
CPL
VOUT
DJNZ
R4RETOUT
CLR
TR1
CLR
ET1
MOV
R404H
SETB
EX0
RETIOUTRETI
外中断0，收到回波时进入
PINT0
CLR
TR0
CLR
TR1
CLR
ET1
CLR
EA
CLR
EX0
MOV
44HTL0
MOV
45HTH0
SETB
00H
RETI
启动计数器T0，用以计算超声来回；开启发超声波用定时器T1
超声波发完毕，关T1开启接收回波中断关计数器
将计数值移入处理单元接收成功标志
f※※※※※※显示程序※※※※※※
；40H为最高位，43H为最低位，先扫描高位
DISPLAYMOV
R140HG
MOV
R50E7HG
PLAY
MOV
AR5
MOV
P00FEH
MOV
P2A
MOV
R1
MOV
DPTRTAB
MOVC
AADPTR
MOV
P0A
LCALL
DL1MS
INC
R1
MOV
AR5
JNB
ACC0ENDOUTG
RR
A
MOV
R5A
AJMP
PLAY
ENDOUT
MOV
P20FEH
MOV
P00FEH
RET
TAB
DB
0C0H0F9H0A4H0B0H99H92H82H0F8H80H90H
0FEH88H0BFH
共阳段码表
“0”，“1”，“2”，“3”，“4”，“5”，“6”，“7”，
“8”，“9”，
“不亮”，“A”，“”
※※※※※※延时程序※※※※※※
DL1MS：DL1DL2
MOVMOVDJNZDJNZRET
R614HR719HR7DL2R6DL1
※※※※※※距离计算程序※※※※※※
Work
PUSHPUSHPUSHMOV
ACCPSWBPSW18h
fJJ0
不亮JJ1
亮JJ2
MOVMOVMOVMOVLCALLMOVMOVLCALLLCALLMOVMOVJNZMOVMOVMOVMOVMOVMOVMOVLCALLMOVMOVJNZMOV
SUBBJNZMOVM0VMOVMOVMOVMOVMOVLCALLMOVMOVJNZMOV
SUBBJNZMOVMOV
R345HR244HR100DR017DMUL2BY2R303HR20E8HDIV4BY2DIV4Y2400HR4A40HJJ040H0AHAR0R4AAR1R5AR300DR2100DDIV4BY241HR4A41HJJ1A40H
最高位为0，不点亮次高位为0，先看最高位是否为
A0AHJJ141H0AH最高位不亮，次高位也不亮AR0R4AAR1R5A
R300DR210DDIV4BY242HR4A42HJJ2A41H次次高位为0，先看次高位是否为不
A0AHJJ242H0AH次高位不亮，次次高位也不亮43HR0
fPOP
B
POP
PSW
POP
ACC
RET
※※※※※※2字节无符号数乘法程序※※※※※※
R7R6R5R4R3R2×R1R0MUL2BY2CLR
MOVMOVMOVMOVMOVMULLOOP1CLRMOVRLCMOVMOVRLCMOVMOVRLCMOVMOVRLCMOVMOVRLCMOVMOVRLCMOVJNCMOVADDMOVMOVADDCMOVMOVADDCMOVMOV
AR7AR6AR5AR4A46H10HCAR4AR4AAR5AR5AAR6AR6AAR7AR7AAR0AR0AAR1AR1AMULLOOP2AR4AR2R4AAR5AR3R5AAR6A00HR6AAR7
fMULLOOP2
ADDCMOVDJNZRET
A00HR7A46HMULLOOP1
※※※※※※4字节2字节无符号数除法程序※※※※※※
；R7R6R5R4R3R2R7R6R5R4商…R1R0余数
DIV4BY2MOV
46H20H
MOV
R000H
MOV
R100H
DIVLOOP1MOV
AR4
RLC
A
MOV
R4A
MOV
AR5
RLC
A
MOV
R5A
MOV
AR6
RLC
A
MOV
R6A
MOV
AR7
RLC
A
MOV
R7A
MOV
AR0
RLC
R0
MOV
R0A
MOV
AR1
RLC
r