text.asm

ATMEL89S52 开机自检程序（需要电路支持）

    ORG 0000H
    JMP MAIN
    ORG 0100H
MAIN:
    MOV SP,#50H
    MOV P2,#00H
    MOV P0,#00H
    LCALL DELAY1
    MOV P0,#00H
    MOV P2,#0BEH
    SETB P2.0
    CLR P2.0
DISPLAY:
    MOV R1,#25H
    MOV R0,#00H
    MOV DPTR,#TAB
LOOP:
    MOV A,R0
    MOVC A,@A+DPTR
    MOV SBUF,A
WAIT:
    JNB TI,WAIT
    CLR TI
    INC R0
    LCALL DELAY2
    DJNZ R1,LOOP
    MOV P0,#0FFH
    SETB P2.6
    CLR  P2.0
    SJMP $
DELAY1:
    MOV R6,#08FH
DL1:
    MOV R7,#0F9H
DL2:
    NOP
    NOP
    DJNZ R7,DL2
    DJNZ R6,DL1
    RET
DELAY2:
    MOV R6,#28H
DL3:
    MOV R7,#0F9H
DL4:
    NOP
    NOP
    DJNZ R7,DL4
    DJNZ R6,DL3
    RET

TAB:
    DB 0FEH,0FDH,0FbH,0F7H,0EFH,0DFH,0bFH,7FH,
    DB 7EH,7DH,7BH,77H,6FH,5FH,3FH,
    DB 3EH,3DH,3BH,37H,2FH,1FH,
    DB 1EH,1DH,1BH,17H,0FH,
    DB 0EH,0DH,0BH,07H,
    DB 06H,05H,03H,
    DB 02H,01H,00H,0FFH