; LCD demo
; By. Engr. Tarique R. Memon
; electronixforu.com 
; XTAL=12MHz
; date february 19, 2009, Thursday

org 0
;***********************initializing Addresses*******************
enable equ p3.7
RW     equ p3.6
RS     equ p3.5
port equ p2
mov p2, #00    ; turn off P2
mov p3, #00    ; turn OFF p3
;***********************starting main program****************
;setb enable

;******************************command section***************
command: mov dptr, #syntax 
               clr RS
               clr RW
loop:  clr a
               movc a, @a+dptr
               jz line1
               setb enable
               mov port, a
               clr enable
               acall delay10ms
               inc dptr
               sjmp loop
               
syntax: db 38h,0fh,01h,10h,00h
;*******************data section*******************
line1:  mov dptr, #mydata
               setb RS
               clr RW
loop1: clr a
               movc a, @a+dptr
               jz command2
               setb enable
               mov port, a
               clr enable
               acall delay10ms
               inc dptr
               sjmp loop1
               
mydata: db '       www.',0
;*******************Line 2
command2: mov dptr, #syntax1 
               clr RS
               clr RW
loop3:  clr a
               movc a, @a+dptr
               jz line2
               setb enable
               mov port, a
               clr enable
               acall delay10ms
               inc dptr
               sjmp loop3
               
syntax1: db 0c0h,00h

;*****************************line 2
line2:  mov dptr, #mydata1
               setb RS
               clr RW
loop2: clr a
               movc a, @a+dptr
               jz return
               setb enable
               mov port, a
               clr enable
               acall delay10ms
               inc dptr
               sjmp loop2
               
mydata1: db 'electronixforu.com',0


return:sjmp return
;*******************delay section*******************



delay10ms:     MOV   R3,#8
                   MOV   R2,#101
               MOV   R1,#115
TT1:           DJNZ  R1,TT1
               DJNZ  R2,TT1
               DJNZ  R3,TT1
               RET
wait:  
               sjmp wait               
               end