Help me! Problem: Using 89C51 to control LCD

lepbinh — Fri, 13 Feb 2004 15:21:45 GMT

Hi!
I have a LCD two line, 20 character per line which name is TC2002A (made in China).
I using 89C51 microcontroler to control it.

And my program to load to 89C51 is writen follow:

; WRITE THE TEXT "HELLO WORLD" TO LCD PROGRAM
; I CONNECT THE PORT P2 OF 89C51 TO DATA BUS OF LCD
; WHERE P2.0, .. P2.7 AND DB0, .. DB7 CONNECT TOGETHER RESPECTIVELY

; AND THESE LINES CONTROL I CONNECT RS TO P3.0; RW TO P3.1; EN TO P3.2

RS BIT P3.0
RW BIT P3.1
EN BIT P3.2

DATA EQU P2
MESS: DB 'HELLO WORLD',0

ORG 0H
AJMP MAIN

SEND_STRING:
; TRANSMIT STRING WHICH POINTED TO BY DPTR.
; STRING MAY BE ANY OF LENGTH, BUT MUST BE MULL-TERMINATED.
SEND:
CLR A
MOVC A, @A+DPTR ; GET CHARACTER
JZ BREAK ; CHECK FOR TERMINATOR

ACALL WRITE_TEXT ; SEND CHARACTER TO LCD
INC DPTR ; POINT TO NEXT CHARACTER
AJMP SEND
BREAK
RET

WAIT_LCD:
SETB EN
CLR RS ; IT'S A COMMAND
SETB RW ; IT'S READ COMMAND
MOV DATA, #0FFH
MOV A,DATA ; READ THE RETURN VALUE
JB ACC.7,WAIT_LCD ; IF BIT 7 HIGH, LCD STILL BUSY
CLR EN ; FINISH THE COMMAND
CLR RW ; TURN OFF RW FOR FUTURE COMMAND
RET

INIT_LCD:
SETB EN
CLR RS ; IT'S A COMMAND
MOV DATA,#06H ; ENTRY MODE SET
CLR EN
LCALL WAIT_LCD
SETB EN
CLR RS
MOV DATA,#0EH ; TURN LCD ON AND THE CURSOR ON (DISPLAY ON/OFF CONTROL)
CLR EN
LCALL WAIT_LCD
SETB EN ; START LCD COMMAND
CLR RS ; IT'S A COMMAND
MOV DATA,#38H ; FUNCTION SET (8 BIT TWO LINE)
CLR EN
LCALL WAIT_LCD

SETB EN ; START LCD COMMAND
CLR RS ; IT'S A COMMAND
MOV DATA,#38H ; FUNCTION SET (8 BIT TWO LINE)
CLR EN
LCALL WAIT_LCD

SETB EN ; START LCD COMMAND
CLR RS ; IT'S A COMMAND
MOV DATA,#80H ; SET DISP RAM ADDR
SETB EN
LCALL WAIT_LCD
RET

CLEAR_LCD:
SETB EN ; START LCD COMMAND
CLR RS ; IT'S A COMMAND
MOV DATA,#01H
CLR EN
LCALL WAIT_LCD
RET

ADD_DDRAM_SET:
SETB EN ; START LCD COMMAND
CLR RS ; IT'S A COMMAND
MOV DATA,#80H
CLR EN
LCALL WAIT_LCD
RET

CURSOR_HOME:
SETB EN
CLR RS ; IT'S A COMMAND
MOV DATA,#02H
CLR EN
LCALL WAIT_LCD
RET

WRITE_TEXT:
SETB EN
SETB RS
MOV DATA,A
CLR EN
LCALL WAIT_LCD
RET

MAIN:
MOV SP,#5FH
CLR RW
LCALL INIT_LCD
LCALL CLEAR_LCD
LCALL ADD_DDRAM_SET
LCALL CURSOR_HOME
MOV DPTR, #MESS
ACALL SEND_STRING
AJMP $
END

; THE END OF PROGRAM

when i build and load the hex file into 89c51 and then turn of the power to run it. I see nothings in lcd, except the character which have ascii is 11111111B in the second line.

What wrongs?
Some once could help me.

Re: Help me! Problem: Using 89C51 to control LCD

Intel_Software_Netw1 — Sat, 21 Feb 2004 08:14:12 GMT

While this questionis outside the scope of topicscovered by Intel Developer Services, Intel does offer technicalsupport for MCS 51 Microcontrollers at this URL:

http://developer.intel.com/design/support/faq/microcontrollers/support_disclaimer.htm

We hope this is helpful.

Regards,

Lexi S.

IntelSoftware NetworkSupport

http://www.intel.com/software

Message Edited by intel.software.network.support on 12-07-2005 03:33 PM

topic Re: Help me! Problem: Using 89C51 to control LCD in Software Archive

Help me! Problem: Using 89C51 to control LCD

Re: Help me! Problem: Using 89C51 to control LCD