用AT89C51制作八位數(shù)字頻率計源程序

ORG????? 00H?????????????? ；指定下條指令的地址

AJMP???? MAIN????????????? ；跳轉(zhuǎn)至MAIN

50M

??????? INC????? 23H

??????? RETI

??????? ORG????? 001BH????????????? ；定時器T1中斷入口，T1作定時，T0作計數(shù)

??????? PUSH???? A????????????????? ；累加器A壓入堆棧

?????? ?PUSH???? PSW??????????????? ；狀態(tài)寄存器壓入堆棧

??????? DJNZ???? 40H，JJ??????????? ；產(chǎn)生1s定時時標

??????? MOV????? 40H，#0C8H

??????? DJNZ???? 41H，JJ

??????? CLR????? P3.1?????????????? ；關(guān)閉閘門

??????? ANL????? 88H，#0AFH???????? ；1s末，關(guān)閉T0和T1

??????? MOV????? 20H，P1

????? ??MOV????? 21H，TL0?????????? ；T0計數(shù)值送21H和22H

? MOV????? 22H，TH0

? SETB???? P3.0?????????????? ；LS393清零

? ACALL??? COUNT??????????? ；調(diào)用二進制轉(zhuǎn)BCD碼程序

JJ：??? POP????? PSW

??????? POP????? A

??????? RETI

??????? ORG????? 50H??????????????? ；以下程序從地址50H開始

MAIN：? MOV????? SP，#50H?????????? ；將初始值賦予SP

MOV????? TH1，#06H????????? ；將初始值賦予TH0