ORG 00H
MAIN:
LCD_RS                EQU P3.5
LCD_RW                EQU P3.6
LCD_EN                EQU P3.7
DYTA                  EQU 50H






;*************
;LCD ROUTINES*
;*************

;INITIALIZE ROUTINE IS FOR INITIALIZING BOTH LCD 4*20 OR 2*16  
;WRITE_ON ROUTINE IS FOR WRITING A LETTER ON LCD
;TRANSFER ROUTINE IS FOR WRITING A MESSAGE ON LCD
;CLEAR_SCREEN ROUTINE IS FOR CLEARING THE SCREEN
;ADDRESS ROUTINE IS FOR LOADING ADDRESS IN DDRAM 
;OTHER LCD ROUTINES ARE SAME WITH NAMES

;FOR EXAMPLE
;MOV A,#80H
;LCALL ADDRESS
;MOV A,#'S'
;LCALL WRITE_ON

;OR
;MOV A,#0C0H
;LCALL ADDRESS
;MOV DPTR,#WORD
;LCALL TRANSFER

;OR

;MOV A,#0C0H
;LCALL ADDRESS
;LCALL CURSOR_BLINK

;**************
;KEYPAD ROUTIN*
;**************

;START ROUTNE IS FOR SCANNING KEYPAD
;FOR EXAMPLE 
;LCALL START
;CJNE A,#1,COMPARE1 ;ACC IS INCLUDED THE RETURNED CODE FROM START ROUTINE
;MEANS THAT IF KEY 1 IS PRESSED THEN ....  
 
;1  2  3  A  >>>   1    2    3    15    15=0FH 
;4  5  6  B  >>>   4    5    6    31    31=1FH
;7  8  9  C  >>>   7    8    9    47    47=2FH
;D  0  E  F  >>>   63   0    79   95    .......
  
  
;RELKEY ROUTINE IS WAITING LOOP UNTIL ALL KEYS IS RELEASED.
  
;SEE LOOK UP TABLE
  

  
  
  

INITIALIZE:
SETB LCD_EN  
CLR LCD_RW 
CLR LCD_RS
MOV P1,#00110000B            
CLR LCD_EN
LCALL DELAY1
SETB LCD_EN  
CLR LCD_RW 
CLR LCD_RS
MOV P1,#00110000B            
CLR LCD_EN
LCALL DELAY1
SETB LCD_EN  
CLR LCD_RW 
CLR LCD_RS
MOV P1,#00110000B            
CLR LCD_EN
LCALL DELAY1
SETB LCD_EN  
CLR LCD_RW 
CLR LCD_RS
MOV P1,#00111000B            
CLR LCD_EN
LCALL DELAY1
SETB LCD_EN  
CLR LCD_RW 
CLR LCD_RS
MOV P1,#00001100B            
CLR LCD_EN
LCALL DELAY1
SETB LCD_EN
CLR LCD_RW
CLR LCD_RS
MOV P1,#00000110B
CLR LCD_EN
LCALL DELAY1
RET

CURSOR_BLINK:
MOV A,#0FH
LCALL COMMAND
RET

CURSOR_OFF:
MOV A,#0CH
LCALL COMMAND
RET

CURSOR_CUSTOM:
MOV A,#0C0H
LCALL COMMAND
RET

SHIFT_LEFT_SCREEN:
MOV A,#18H
LCALL COMMAND
RET

SHIFT_RIGHT_SCREEN:
MOV A,#1CH
LCALL COMMAND
RET

COMMAND:
MOV P1,A
SETB LCD_EN
CLR LCD_RW
CLR LCD_RS
LCALL DELAY0
CLR LCD_EN
LCALL DELAY0
RET 

CLEAR_SCREEN:
SETB LCD_EN
CLR LCD_RS
CLR LCD_RW
MOV P1,#00000001B
LCALL DELAY0
CLR LCD_EN
LCALL DELAY0
RET


ADDRESS:
SETB LCD_EN
CLR LCD_RW
CLR LCD_RS
MOV P1,A
LCALL DELAY0
CLR LCD_EN
LCALL DELAY0
RET

WRITE_ON:
MOV P1,A
SETB LCD_EN
CLR LCD_RW
SETB LCD_RS
LCALL DELAY0
CLR LCD_EN
LCALL DELAY0
LCALL DELAY0
RET 

TRANSFER:
CLR A
MOVC A,@A+DPTR
INC DPTR
CJNE A,#0FFH,TRANS
LJMP EXIT3
TRANS:
MOV P1,A
LCALL WRITE_ON
LJMP TRANSFER
EXIT3:
RET

START:
  LCALL  RELKEY
  LCALL START0
  RET


START0:
SUB_0:
  MOV    R3,#04H
  MOV    R2,#0FEH
  MOV    R4,#00H
SUB_1:
  MOV    A,R2
  MOV    P0,A
  LCALL  DELAY2
  MOV    A,P0
  ANL    A,#0F0H
  CJNE   A,#0F0H,SUB_2
  INC    R4
  MOV    A,R2
  RL     A
  MOV    R2,A
  DJNZ   R3,SUB_1
  LJMP   SUB_0
SUB_2:
  CJNE   A,#0E0H,SUB_3
  MOV    R6,#00H
  LJMP   SUB_7
SUB_3:
  CJNE   A,#0D0H,SUB_5
SUB_4:
  MOV    R6,#01H
  LJMP   SUB_7
SUB_5:
  CJNE   A,#0B0H,SUB_6
  MOV    R6,#02H
  LJMP   SUB_7
SUB_6:
  CJNE   A,#70H,SUB_01
  MOV    R6,#03H
SUB_7:
  MOV    A,R4
  MOV DPTR,#INTIGER
  MOV    B,#4
  MUL    AB
  ADD    A,R6
  MOVC   A,@A+DPTR
  MOV    DYTA,A
  MOV A,DYTA
SUB_01:
  RET


RELKEY:
  CLR  LCD_EN  
  MOV DYTA,A
  L_0438:
  MOV    P0,#0F0H
  LCALL DELAY0
  MOV    A,P0
  ANL A,#0F0H
  CJNE   A,#0F0H,L_0438
  MOV A,DYTA
  RET



;****************************************
;****************************************
;****************************************
;****************************************
;****************************************

DELAY0:
PUSH 7
MOV R7,#1
SUB_DELAY:
MOV TMOD,#00000001B
MOV TH0,#0FCH
MOV TL0,#00H
SETB TR0
TF0?:
JNB TF0,TF0?
CLR TR0
CLR TF0
DJNZ R7,SUB_DELAY
POP 7
RET


DELAY1:
PUSH 7
MOV R7,#1
SUB_DELAY1Z:
MOV TMOD,#00000001B
MOV TH0,#0A0H 
MOV TL0,#00H
SETB TR0
TF0??:
JNB TF0,TF0??
CLR TR0
CLR TF0
DJNZ R7,SUB_DELAY1Z
POP 7
RET


DELAY2:
PUSH 7
MOV R7,#1
SUB_DELAY1B:
MOV TMOD,#00000001B
MOV TH0,#0D5H
MOV TL0,#68H
SETB TR0
TF0??????:
JNB TF0,TF0??????
CLR TR0
CLR TF0
DJNZ R7,SUB_DELAY1B
POP 7
RET

INTIGER:            DB 1,2,3,15,4,5,6,31,7,8,9,47,63,0,79,95
END