I try writing a string instead of writing letter by letter. So, I tried this code:
but the DPTR value is increasing until infinity and the string is not written on the LCD
what should I do to solve this problem ?
LCD:
ORG 00H
RS BIT P2.7
E BIT P2.6
MOV SP, #25H
MOV P1, #00H
MOV P2, #00H
MOV TMOD, #01H
;;;;;;;;;;;;;;;;;;;;;;;;;;;COMMANDS;;;;;;;;;;;;;;;;;;;;;;;;;;;
ACALL COMMANDS
;;;;;;;;;;;;;;;;;;;;;;;;;;;PRINTING;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
MOV DPTR, #STRING1
ACALL STRING_PRNT
;;;;;;;;;;;;;;;;;;;;;;;;;;;NO LOOPING;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
HERE: SJMP HERE
;;;;;;;;;;;;;;;;;;;;;;;;;;;COMMAND FUNCTION;;;;;;;;;;;;;;;;;;;;;;;;;;
COMMANDS:
MOV R1, #32H
ACALL DELAY_MS
MOV P1, #30H ;8-BIT INITIALIZATION
CLR RS ;COMMAND MODE
SETB E
ACALL DELAY_MS
CLR E
ACALL DELAY_MS
MOV R1, #05H ; 5MS DELAY
ACALL DELAY_MS
MOV P1, #30H ;8-BIT INITIALIZATION
CLR RS ;COMMAND MODE
SETB E
ACALL DELAY_MS
CLR E
ACALL DELAY_MS
MOV R1, #0DH ; 4MS DELAY
ACALL DELAY_US
MOV P1, #30H ;8-BIT INITIALIZATION
CLR RS ;COMMAND MODE
SETB E
ACALL DELAY_MS
CLR E
ACALL DELAY_MS
MOV R1, #0DH ; 4MS DELAY
ACALL DELAY_US
MOV P1, #20H ;4-BIT WITH 1 LINE INITIALIZATION
CLR RS ;COMMAND MODE
SETB E
ACALL DELAY_MS
CLR E
ACALL DELAY_MS
MOV R1, #0DH ;50 MICROSECONDS DELAY
ACALL DELAY_US
MOV R0, #28H ;4-BIT MODE OF LCD INITIALIZATION
ACALL CMD
MOV R1, #0DH ;50 MICROSECONDS DELAY
ACALL DELAY_US
MOV R0, #08H ;DISPLAY ON, CURSOR ON
ACALL CMD
MOV R1, #05H ;50 MICROSECONDS DELAY
ACALL DELAY_US
MOV R0, #01H ;CLEAR LCD
ACALL CMD
MOV R1, #02H ;2 MS DELAY
ACALL DELAY_MS
MOV R0, #06H ;ENTRY MODE
ACALL CMD
MOV R1, #05H ;50 MICROSECONDS DELAY
ACALL DELAY_US
MOV R0, #0EH
ACALL CMD
MOV R1, #05H
ACALL DELAY_US
MOV R0, #80H ;HOME CURSOR
ACALL CMD
MOV R1, #02H ;2 MS DELAY
ACALL DELAY_MS
MOV R1, #14H ;20 MS DELAY
ACALL DELAY_MS
RET
CMD:
;SENDING THE UPPER NIBBLE
MOV A, R0
ANL A, #0F0H
MOV P1, A
CLR RS ;COMMAND MODE
SETB E
MOV R1, #01H
ACALL DELAY_MS
CLR E
MOV R1, #01H
ACALL DELAY_MS
;SENDING THE LOWER NIBBLE
MOV A, R0
ANL A, #0FH
SWAP A
MOV P1, A
CLR RS
SETB E
MOV R1, #01H
ACALL DELAY_MS
CLR E
MOV R1, #01H
ACALL DELAY_MS
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;PRINT FUNCTION;;;;;;;;;;;;;;;;;;;;;;;;;;;
PRNT:
MOV R0, #0EH
ACALL CMD
MOV R1, #05H
ACALL DELAY_US
;SENDING THE UPPER NIBBLE
MOV A, R0
ANL A, #0F0H
MOV P1, A
SETB RS ;DATA MODE
SETB E
MOV R1, #01H
ACALL DELAY_MS
CLR E
MOV R1, #01H
ACALL DELAY_MS
;SENDING THE LOWER NIBBLE
MOV A, R0
ANL A, #0FH
SWAP A
MOV P1, A
SETB RS
SETB E
MOV R1, #01H
ACALL DELAY_MS
CLR E
MOV R1, #01H
ACALL DELAY_MS
MOV R0, #0CH
ACALL CMD
MOV R1, #05H
ACALL DELAY_US
MOV R1, #01H
ACALL DELAY_MS
RET
STRING_PRNT:
CLR A
MOVC A, @ A + DPTR
MOV R0, A
ACALL PRNT
INC DPTR
JZ SAD
SJMP STRING_PRNT
SAD: RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;DELAY FUNCTION;;;;;;;;;;;;;;;;;;;;;;;;;;
DELAY_MS:
MOV TH0, #0F8H
MOV TL0, #30H
SETB TR0
LOOP: JNB TF0, LOOP
CLR TR0
CLR TF0
DJNZ R1, DELAY_MS
RET
DELAY_US: MOV TH0, #0FFH
MOV TL0, #0ECH
SETB TR0
LOOP1: JNB TF0, LOOP1
CLR TR0
CLR TF0
DJNZ R1, DELAY_US
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
ORG 500H
STRING1: DB "HELLO WORLD",0
ENDwhat should I do to solve this problem ?
