Emonk Posted July 17, 2010 Report Posted July 17, 2010 (edited) I use the code in the attachment, and it's my idea it will give me on my LCDisplay the letters "Camil" (and yes, that is my name) All the first subroutines i just copied form http://home.iae.nl/users/pouweha/lcd/lcd2.shtml - it has to work. From label start i did make anything myself. I'm sure i did connect the LCD and the PIC right, and i am sure the contrast is OK. I just think i don't understand how to use the subroutines. What happens is the following: the backlight does work, but there isn't any character. What's the problem - how do I solve it? And: I'm dutch, and my english isn't very well - could you please try to make your sentences easy?? :smile: Thanks for your help! here does the program stay too: ;********************************************************************** ; * ; Filename: LCDisplay test.asm * ; Date: 17/7/2010 * ; File Version: v1.0 * ; * ; Author: Camil Staps * ; Company: none * ; * ; * ;********************************************************************** ; * ; Files Required: P16F84A.INC * ; * ;********************************************************************** ; * ; Notes: * ; * ;********************************************************************** list p=16F84A ; list directive to define processor #include <p16F84A.inc> ; processor specific variable definitions __CONFIG _CP_OFF & _WDT_OFF & _PWRTE_ON & _XT_OSC ;********************************************************************** ORG 0000h ; processor reset vector GOTO start ; go to beginning of program ORG 0004h ; interrupt vector location GOTO start ;********************************************************************** lcdinit LCD_DATA EQU 06h ; PORTB LCD_DATA_TRIS EQU 86h ; TRISB LCD_CTRL EQU 05h ; PORTA LCD_TEMP EQU 0x020 DELAY EQU 0x023 X_DELAY EQU 0x024 ; PORTA Control Bits LCD_E EQU 02h ; Enable LCD_RW EQU 01h ; Read/Write LCD_RS EQU 00h ; Register Select CLRF LCD_CTRL ; all RA on 0 MOVLW 0x01E CALL X_DELAY500 MOVLW 0x038 CALL lcdputcmd MOVLW 0x000 CALL lcddmode ; disp.off, curs.off, noblink CALL lcdclear MOVLW 0x004 CALL lcddmode ; disp.on, curs.off MOVLW 0x002 CALL lcdemode ; auto-inc (shift-cursor) RETURN ;********************************************************************** ;Busy Flag lcdbusy BSF 03h,05h ; bank 1 MOVLW 0x0FF MOVWF LCD_DATA_TRIS ; PORTB input BCF 83h,05h ; bank 0 BCF LCD_CTRL,LCD_RS ; LCD Command Mode BSF LCD_CTRL,LCD_RW ; Setup busy flag BSF LCD_CTRL,LCD_E ; LCD Enable hoog MOVF LCD_DATA,0 BCF LCD_CTRL,LCD_E ; LCD Enable low ANDLW 0x080 ; check busy flag, high=busy BTFSS 03h,02h ; Zero Flag GOTO lcdbusy ; still busy... lcdnotbusy BCF LCD_CTRL,LCD_RW BSF 03h,05h CLRF LCD_DATA_TRIS ; PORTB output BCF 83h,05h RETURN ;Clear Display lcdclear MOVLW 0x001 CALL lcdputcmd RETURN ;Cursor Home lcdhome MOVLW 0x002 CALL lcdputcmd RETURN ;Entry Mode lcdemode ANDLW 0x003 IORLW 0x004 CALL lcdputcmd RETURN ;Display Mode lcddmode ANDLW 0x007 IORLW 0x008 CALL lcdputcmd RETURN ;Set Character generator RAM address lcdscga ANDLW 0x03F IORLW 0x040 CALL lcdputcmd RETURN ;Set Display data RAM address lcdsdda IORLW 0x080 CALL lcdputcmd RETURN ;Get address counter contents lcdgaddr BSF 03h,05h MOVLW 0x0FF ; PORTB input MOVWF LCD_DATA_TRIS BCF 83h,05h BCF LCD_CTRL,LCD_RS ; command mode BSF LCD_CTRL,LCD_RW ; setup busy flag BSF LCD_CTRL,LCD_E ; Enable high MOVF LCD_DATA,0 ; data to W register BCF LCD_CTRL,LCD_E ; Enable low ANDLW 0x07F BCF LCD_CTRL,LCD_RW BSF 03h,05h CLRF LCD_DATA_TRIS ; PORTB output BCF 83h,05h RETURN ;Write Character lcdputchar MOVWF LCD_TEMP ; char is in W CALL lcdbusy BCF LCD_CTRL,LCD_RW ; Read mode BSF LCD_CTRL,LCD_RS ; Data mode BSF LCD_CTRL,LCD_E ; Enable high MOVF LCD_TEMP,0 ; char back to W MOVWF LCD_DATA ; data to LCD BCF LCD_CTRL,LCD_E ; Enable low RETURN ;Write Command lcdputcmd MOVWF LCD_TEMP ; Command is in W CALL lcdbusy BCF LCD_CTRL,LCD_RW ; Read mode BCF LCD_CTRL,LCD_RS ; Command mode BSF LCD_CTRL,LCD_E ; Enable high MOVF LCD_TEMP,0 ; char back to W MOVWF LCD_DATA ; command to LCD BCF LCD_CTRL,LCD_E ; Enable low RETURN DELAY500 MOVLW D'165' MOVWF DELAY DELAY500_LOOP DECFSZ DELAY,1 GOTO DELAY500_LOOP RETURN X_DELAY500 MOVWF X_DELAY X_DELAY500_LOOP CALL DELAY500 DECFSZ X_DELAY,1 GOTO X_DELAY500_LOOP RETURN ;Here does my program start start CALL lcdinit MOVLW b'01000011' ; C CALL lcdputchar MOVLW b'01100001' ; a CALL lcdputchar MOVLW b'01101101' ; m CALL lcdputchar MOVLW b'01101001' ; i CALL lcdputchar MOVLW b'01101100' ; l CALL lcdputchar loop GOTO loop END ; directive 'end of program' Edited July 17, 2010 by Emonk
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