;Displaying "YES" on LCD Connected to MDE 8051 Trainer
;Modified and tested by M. Mazidi from prog 12-1 of 8051 Microcontroller book by Mazidis & McKinlay 
;P1.7-P1.0 is connected to D7-D0 of LCD
;P2.0=RS, P2.1=R/W, and P2.2=E (see chapter 12)

 			
 			ORG	 0
 			ACALL	DELAY 
 			ACALL	DELAY 
 			MOV	A,#38H		
			ACALL	COMNWRT    	
			ACALL	DELAY      	
			MOV	A,#0EH     	
			ACALL	COMNWRT		
			ACALL	DELAY		
			MOV	A,#01     	
			ACALL	COMNWRT    	
			ACALL	DELAY		
			MOV	A,#06H     	
			ACALL	COMNWRT    	
			ACALL	DELAY		
			MOV	A,#84H     	
			ACALL	COMNWRT    	
			ACALL	DELAY		
			MOV	A,#'Y'     	
			ACALL	DATAWRT    	
			ACALL	DELAY		
			MOV	A,#'E'     	
			ACALL	DATAWRT 
 			ACALL	DELAY		
			MOV	A,#'S'     	
			ACALL	DATAWRT 
AGAIN:			SJMP	AGAIN      	
COMNWRT:                   	
			MOV	P1,A       	
			CLR	P2.0       	
			CLR	P2.1       	
			SETB	P2.2       	
			ACALL	DELAY		
			CLR	P2.2       	
			RET
DATAWRT:                   	
			MOV	P1,A       	
			SETB	P2.0       	
			CLR	P2.1       	
			SETB	P2.2       	
			ACALL	DELAY		
			CLR	P2.2       	
			RET
			
;-------------------------
;200 msec. delay for DS89C4x0 with MDE8051 Trainer
;XTAL=11.0592 MHz on MDE8051
;9 x 255 x 242 x 4 x 90 ns = 199 msec
;Notice DS89C4x0 uses 4 clocks for Machine Cycle. 
   			
DELAY:
		MOV	 R5, #9
H3:		MOV	 R4, #242    
H2:  		MOV	 R3, #255    
H1:	 	DJNZ	 R3, H1 		
    		DJNZ	 R4, H2  
    		DJNZ	 R5, H3  
   		RET             
		   END