delay.asm

This ia a delay program for 8051

; Chip P89C51RD2 & 2051, Crystal 6 MHz, 12 CLK Mode.
		$TITLE(PROGRAM FOR 0.1m Sec.DELAY) 
		$DATE(14-10-04)
		$MOD51
		ORG 0H
	BACK:	;MOV P0,A   	;send 55H to port 0
		;MOV P1,A   	;send 55H to port 1
        MOV P2,A   	;send 55H to port 2
		;MOV P3,A   	;send 55H to port 3
        ACALL DELAY4	;time delay
		CPL A		;Load A with AA
		SJMP BACK	;keep doing this 

		ORG 100H
             ;Delay for 2.5mSec.
DELAY4:		;ORG 0A0H
			;MOV R2,#25	;1 Machine cycle
			;NOP
			;NOP
			;NOP
			;NOP
			;NOP
			;NOP 
			;NOP
LOOP4:		MOV R3,#245	;1 Machine cycle  
LOOP5:		DJNZ R3,LOOP5	;2 Machine cycle, loop3 total 4 machine cycle X 250
			;DJNZ R2,LOOP4	;2 Machine cycle
			RET	
            END