jianyimiaobiao.asm

单片机简易秒表

TCNTA EQU 30H 
TCNTB EQU 31H 
SEC EQU 32H 
KEYCNT EQU 33H 
SP1 BIT P3.5 
ORG 00H 
LJMP START 
ORG 0BH 
LJMP INT_T0 

START: MOV KEYCNT,#00H 
MOV SEC,#00H 
MOV A,SEC 
MOV B,#10 
DIV AB 
MOV DPTR,#TABLE 
MOVC A,@A+DPTR 
MOV P0,A 
MOV A,B 
MOV DPTR,#TABLE 
MOVC A,@A+DPTR 
MOV P2,A 
MOV TMOD,#02H 
SETB ET0 
SETB EA 

WT: JB SP1,WT 
LCALL DELY10MS 
JB SP1,WT 
INC KEYCNT 
MOV A,KEYCNT 
CJNE A,#01H,KN1 
SETB TR0 
MOV TH0,#06H 
MOV TL0,#06H 
MOV TCNTA,#00H 
MOV TCNTB,#00H 
LJMP DKN 

KN1: CJNE A,#02H,KN2 
CLR TR0 
LJMP DKN 

KN2: CJNE A,#03H,DKN 
MOV SEC,#00H 
MOV A,SEC 
MOV B,#10 
DIV AB 
MOV DPTR,#TABLE 
MOVC A,@A+DPTR 
MOV P0,A 
MOV A,B 
MOV DPTR,#TABLE 
MOVC A,@A+DPTR 
MOV P2,A 
MOV KEYCNT,#00H 

DKN: JNB SP1,$ 
LJMP WT 

DELY10MS: 
MOV R6,#20 
D1: MOV R7,#248 
DJNZ R7,$ 
DJNZ R6,D1 
RET 

INT_T0: 
INC TCNTA 
MOV A,TCNTA 
CJNE A,#100,NEXT 
MOV TCNTA,#00H 
INC TCNTB 
MOV A,TCNTB 
CJNE A,#4,NEXT 
MOV TCNTB,#00H 
INC SEC 
MOV A,SEC
CJNE A,#100,DONE 
MOV SEC,#00H 

DONE: MOV A,SEC 
MOV B,#10 
DIV AB 
MOV DPTR,#TABLE 
MOVC A,@A+DPTR 
MOV P0,A 
MOV A,B 
MOV DPTR,#TABLE 
MOVC A,@A+DPTR 
MOV P2,A 

NEXT: RETI 

TABLE: DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH 

END