keypad and LCD interfacing to 8051 (code in .asm)

Hi

The following is the code to interface a 4x4 0r 4x3 keypad across P0 of 8051 based controllers
Here i also interfaced an LCD to display the pressed characters. LCD is interfaced across P1 of the controller.

I used LCD in 4 bit mode
P1.2 is used as Register select pin for LCD
P1.3 is used as EN pin for LCD
P1.4 to P1.7 are used as data pins


org 0000h
;MOV P1,#00H
ACALL LCD_INIT
MOV A,#'K'
ACALL DATAWRT
ACALL DELAY
mov P0,#0fh ;P0.7 to P0.4 output(row) and P0.3 to P0.0 input(col)

K1:
mov p0,#0fh
mov a,P0
anl a,#0fh
mov P0,a
mov a,P0
anl a,#0fh
cjne a,#0fh,K1

K2:acall delay2
mov a,P0
anl a,#0fh
cjne a,#0fh,over
sjmp K2

OVER:
acall delay2
mov a,P0
anl a,#0fh
cjne a,#0fh,over1
sjmp k2

OVER1:
clr P0.4 ; row 1 selected
setb P0.5
setb P0.6
setb P0.7

mov a,P0
anl a,#0fh
cjne a,#0fh,ROW0

clr P0.5 ; row 2 selected
setb P0.7
setb P0.6
setb P0.4

mov a,P0
anl a,#0fh
cjne a,#0fh,ROW1

clr P0.6 ; row 3 selected
setb P0.7
setb P0.5
setb P0.4

mov a,P0
anl a,#0fh
cjne a,#0fh,ROW2

clr P0.7 ; row 4 selected
setb P0.4
setb P0.6
setb P0.5

mov a,P0
anl a,#0fh
cjne a,#0fh,ROW3

sjmp k2
mov r0,#04h

ROW0: MOV DPTR,#KCODE0
SJMP FIND
ROW1: MOV DPTR,#KCODE1
SJMP FIND
ROW2: MOV DPTR,#KCODE2
SJMP FIND
ROW3: MOV DPTR,#KCODE3
FIND: RRC A
JNC MATCH
INC DPTR
djnz r0,FIND
MATCH:
CLR A
MOVC A,@A+DPTR
ACALL DATAWRT
LJMP K1

LCD_INIT:


; ACALL DELAY
ACALL DELAY
ACALL DELAY
MOV A,#30H
ACALL COMMD
ACALL DELAY

MOV A,#30H
ACALL COMMD
ACALL DELAY

MOV A,#30H
ACALL COMMD
ACALL DELAY

MOV A,#02H
ACALL COMMD
ACALL DELAY

MOV A,#01H
ACALL COMMD
ACALL DELAY

MOV A,#0CH
ACALL COMMD
ACALL DELAY

MOV A,#80H
ACALL COMMD
ACALL DELAY
RET

COMMD:
MOV R4,A
ANL A,#0F0H
MOV P1,A ;P1 FOR LCD
CLR P1.2 ;RS=0 COMMAND REG
SETB P1.3 ;ENABLE PIN
NOP
CLR P1.3
ACALL DELAY
MOV A,R4
SWAP A
ANL A,#0F0H
MOV P1,A
CLR P1.2
SETB P1.3
NOP
CLR P1.3
RET

DATAWRT:
ACALL DELAY
MOV R4,A
ANL A,#0F0H
MOV P1,A
SETB P1.2 ;RS=1
SETB P1.3
NOP
CLR P1.3
MOV A,R4
SWAP A
ANL A,#0F0H
MOV P1,A
SETB P1.2
SETB P1.3
NOP
CLR P1.3
RET

DELAY:
MOV R0,#7FH
AGAIN:MOV R1,#0FFH
HERE: DJNZ R1,HERE
DJNZ R0,AGAIN
RET

DELAY2:
MOV R0,#25H
AGAIN2:MOV R1,#0FFH
HERE2: DJNZ R1,HERE2
DJNZ R0,AGAIN2
RET


KCODE0: DB 'A ','#','0','*'
KCODE1: DB 'B ','9','8','7'
KCODE2: DB 'C ','6','5','4'
KCODE3: DB ' D','3','2','1'

END