;----------------------------------------------------------------------------------------;
;THIS IS A 16X2 LCD DRIVING ROUTINE YOU CAN ADD IT TO YOUR CODES FOR DISPLAYING          ;
;DATA OR MESSAGES ON AN LCD.                                                             ;
;IF YOU WANT TO LEARN MORE ABOUT LCDs TRY THE FOLLOWING LINKS:                           ;
;   http://www.geocities.com/kool_projects/lcd1.pdf                                      ;
;and                                                                                     ;
;   http://www.geocities.com/kool_projects/lcd2.pdf                                      ; 
;----------------------------------------------------------------------------------------;
;This code is written by Mubashar Yasin(Islamabad,Pakistan).It is freely distributable   ;
;however please distribute it with my name and if you add this code to your website or   ;
;some other publication then mention about me along with this code.I have tested this    ;
;code to work properly even then there is no guarantee or warranty and i cannot be held  ; 
;responsible for any damage or loss due to this code.If you have any querries about this ; 
;code please contact me at:                                                              ;
;                                                                                        ;
;  kool_projects@yahoo.com                                                               ;
;  mubasharpk09@hotmail.com                                                              ;
;                                                                                        ;
;or visit my website:                                                                    ;
;                                                                                        ;
;  http://www.geocities.com/kool_projects                                                ;
;----------------------------------------------------------------------------------------;	
	




	EN EQU P3.5
	RW EQU P3.6
	RS EQU P3.7
	DAT EQU P1

	
	ORG 0000H
	LJMP MAIN

STRING1: DB '  MUBASHAR YASIN  ',0H
STRING2: DB '   ELECT. ENGG.   ',0H

;;;;;;;;;;;;;;;;;
INIT_LCD:
;;;;;;;;;;;;;;;;;
	CLR RS
	MOV DAT,#38h ;8-BIT DATA LINE, 5X8 DOT CHARACTER FONT
	SETB EN
	CLR EN
	LCALL WAIT_LCD 
	CLR RS
	MOV DAT,#0Eh  ;TURN ON (LCD + CURSOR)
	SETB EN
	CLR EN
	LCALL WAIT_LCD
	CLR RS
	MOV DAT,#06h  ;SHIFT THE CURSOR ONE POSITION RIGHT WHEN A CHAR. IS WRITTEN 
	SETB EN
	CLR EN
	LCALL WAIT_LCD
	RET
;;;;;;;;;;;;;;;;;
WAIT_LCD:
;;;;;;;;;;;;;;;;;
        	
WAIT:	CLR RS ;It's a command
	SETB RW ;It's a read command
	MOV DAT,#0xFF ;Set all pins to FF initially
	CLR EN ;Clock out command to LCD
	SETB EN;Status out
	JB P1.7,WAIT ;If bit 7 high, LCD still busy
	CLR EN ;Finish the command
	CLR RW ;Turn off RW for future commands
	RET
;;;;;;;;;;;;;;;;;
CLEAR_LCD:
;;;;;;;;;;;;;;;;;
	CLR RS
	MOV DAT,#01h
	SETB EN
	CLR EN
	LCALL WAIT_LCD
	RET
;;;;;;;;;;;;;;;;;
WRITE_CHAR:
;;;;;;;;;;;;;;;;;
	SETB RS
	MOV DAT,A
	SETB EN
	CLR EN
	LCALL WAIT_LCD
	RET
;;;;;;;;;;;;;;;;;
WRITE_STRING:
;;;;;;;;;;;;;;;;;
	MOV R0,#0H
RPT:	MOV A,R0
	MOVC A,@A+DPTR
	JZ EXIT1
	LCALL WRITE_CHAR
	INC R0
	LJMP RPT
EXIT1:	RET
;;;;;;;;;;;;;;;;;
SELECT_LINE1:
;;;;;;;;;;;;;;;;;
	CLR RS
	MOV DAT,#080H ;PLACE CURSOR ON FIRST LINE
	SETB EN
	CLR EN
	LCALL WAIT_LCD
	RET
;;;;;;;;;;;;;;;;;
SELECT_LINE2:
;;;;;;;;;;;;;;;;;
	CLR RS
	MOV DAT,#0C0H ;PLACE CURSOR ON SECOND LINE
	SETB EN
	CLR EN
	LCALL WAIT_LCD
	RET
;;;;;;;;;;;;;;;;;
MAIN:
;;;;;;;;;;;;;;;;;
	CLR RW
	LCALL INIT_LCD
	LCALL CLEAR_LCD
	LCALL SELECT_LINE1
	MOV DPTR,#STRING1
	LCALL WRITE_STRING
	LCALL SELECT_LINE2
	MOV DPTR,#STRING2
	LCALL WRITE_STRING
	JMP $
	END