please dont rip this site
		;
		; LCD module commands and utilities
		;
		;*********************************************************************
DisLCD	; disable lcd module output
		;*********************************************************************
		; install this command in the CmdMenu lookup table
	CmdPC = $						; save current inline assembly PC value
	org CurCmdMenuAdr				; set assembly PC to addr for new entry
	; CmdMenu table entry
	data	"LCDOFF\r", CmdPC, "Disable LCD output\r\n"
	CurCmdMenuAdr = $				; set current CmdMenu addr for next entry
	org CmdPC						; begin cmd code gen at inline address
		bcf		lcdFlags, LCDPrsnt	; clear lcd present flag
		goto	DspLCD				; go display lcd status
		;
		;*********************************************************************
EnLCD	; enable lcd module output
		;*********************************************************************
		; install this command in the CmdMenu lookup table
	CmdPC = $						; save current inline assembly PC value
	org CurCmdMenuAdr				; set assembly PC to addr for new entry
	; CmdMenu table entry
	data	"LCDON\r", CmdPC, "Enable LCD output\r\n"
	CurCmdMenuAdr = $				; set current CmdMenu addr for next entry
	org CmdPC						; begin cmd code gen at inline address
		call	INIT_LCD			; initialize lcd module
		bsf		lcdFlags, LCDPrsnt	; set lcd present flag
		; fall through to display lcd status
		;
		;*********************************************************************
DspLCD	; display lcd module status
		;*********************************************************************
		; install this command in the CmdMenu lookup table
	CmdPC = $						; save current inline assembly PC value
	org CurCmdMenuAdr				; set assembly PC to addr for new entry
	; CmdMenu table entry
	data	"LCD\r", CmdPC, "Display LCD status\r\n"
	CurCmdMenuAdr = $				; set current CmdMenu addr for next entry
	org CmdPC						; begin cmd code gen at inline address
		; copy first part of output string into output buffer using FSR0
		CpyTbl2Out	LcdD
		btfsc	lcdFlags, LCDPrsnt	; if lcd isn't present then skip
		goto	LCDcont				; otherwise don't print NOT
		CpyTbl2Out	NotD			; print NOT
LCDcont	CpyTbl2Out	ActiveD			; complete output string
		return						; return from Cmd
		; This is the end of the functions executable code
		;
		; These data statements store constant ascii output strings in program 
		;  memory. They're accessed using the CpyTbl2Buf and CpyTblCont macros 
		;  with the addresses given by the labels.
LcdD	; constant string for lcd status display
	data	"\nLCD module is ",0
NotD	; constant string for NOT display
	data	"NOT ",0
ActiveD	; constant string for active display
	data	"active\n",0
		;
		; additional LCD routines
		;
InitLCD
		clrf	lcdFlags			; initalize lcd flags
		return
		;
Cmd2LCD	; send cmd line to LCD
		btfss	lcdFlags, LCDPrsnt	; skip if lcd present flag is set
		return						; otherwise return
		movlw	0x0D				; load CR char
		call	SEND_CHAR			; send it to LCD
		movlw	0x0A				; load LF char
		call	SEND_CHAR			; send it to LCD
		movlw	'>'					; load prompt char
		call	SEND_CHAR			; send it to LCD
		movfp	rxPtr, FSR0
LineLCD	incf	FSR0
		movfp	INDF0, WREG
		call	SEND_CHAR
		movlw	0x0D
		cpfseq	INDF0
		goto	LineLCD
		return
		;
Out2LCD	; send output line to LCD
		btfss	lcdFlags, LCDPrsnt	; skip if lcd present flag is set
		return						; otherwise return
		movfp	txPtr, FSR0
OutLCD	tstfsz	INDF0
		goto	$+2
		return
		movfp	INDF0, WREG
		call	SEND_CHAR
		incf	FSR0
		goto	OutLCD
;
; LM032L lcd module initialization and interface routines and variables
;	writteb in 17Cxx assembly.
;
;	include this file after the cblock and org statement in the main file
;
;	The interface is defined as 4 bit using D0-D3 of the port LCD defined
;   below. The control signals are on the upper nibble of the same port.

;
; set the port used for the LCD interface here
LCD				EQU     PORTC			; on the '756 demo board the LCD i/f is 
LCD_DDR			EQU     DDRC			; on PORTC
LCD_BNK			EQU		1				; which is in bank 1
;
; LCD Control Signal names.
;
E				EQU		6				; LCD Enable control line
RW				EQU		5				; LCD Read/Write control line
RS				EQU		4				; LCD Register Select control line
;
; set the dewice frequency here
Dev_Freq		EQU		D'16000000'			; Device Frequency is 4 MHz
LCD_INIT_DELAY	EQU		(HIGH ((( Dev_Freq / 4 ) * D'46' / D'10000' ) / 3 ) ) + 1
;
; LCD Module commands
;
DISP_ON			EQU		0x00C			; Display on
DISP_ON_C		EQU		0x00E			; Display on, Cursor on
DISP_ON_B		EQU		0x00F			; Display on, Cursor on, Blink cursor
DISP_OFF		EQU		0x008			; Display off
CLR_DISP		EQU		0x001			; Clear the Display
ENTRY_INC		EQU		0x006			;
ENTRY_INC_S		EQU		0x007			;
ENTRY_DEC		EQU		0x004			;
ENTRY_DEC_S		EQU		0x005			;
DD_RAM_ADDR		EQU		0x080			; Least Significant 7-bit are for address
DD_RAM_UL		EQU		0x080			; Upper Left coner of the Display
CURS_LEFT		EQU		0x10			; shift cursor left
CURS_RIGHT		EQU		0x14			; shift cursor right
;
	cblock					; variable declaration 
		lcdFlags			; status flags for LCD module
		temp				; used by SEND_CHAR and SEND_CMD
		busyread			; used by BUSY_CHECK
		TEMP0				; used for delay in INIT_LCD
		TEMP1				;	"			"
	endc
	; high active flags in lcdFlags
	LCDPrsnt	equ	0		; lcd module is present
;
;
;*******************************************************************
;* The LCD Module Subroutines                                      *
;*******************************************************************
;
;*******************************************************************
;* SEND_CHAR - Sends character in W to LCD                         *
;* This routine splits the character into the upper and lower      * 
;* nibbles and sends them to the LCD, upper nibble first.          *
;* The data is transmitted on the PORT<3:0> pins                   *
;*  Affects:  W and temp                                           *
;*******************************************************************
;
SEND_CHAR
		movlb	LCD_BNK				; select SFR bank for LCD
		movwf	temp				; save char to be sent
		call	BUSY_CHECK			; wait for LCD ready

;		movfp	busyread, WREG		; DEBUG fetch last cursor position
;		movwf	PORTD				; DEBUG display on leds

		movlw	0x08				; test for backspace
		cpfseq	temp
		goto	NOT_BACK			; if not keep going
		; process backspace with wrap araound
		movfp	busyread, WREG		; fetch cursor position
		bcf		WREG, 6				; clear row indicating bit
		tstfsz	WREG				; skip if 0 to process wrap
		goto	NOWRAP				; otherwise no wrap around

		movfp	busyread, WREG		; fetch cursor position
		btg		WREG, 6				; toggle row
		iorlw	D'19'				; set to last visible location
		bsf		WREG, 7				; set bit to create load addr cmd
		call	SEND_CMD			; send to display
		movlw	' '					; load space char to clear spot
		call	SEND_CHAR			; recursively call to send
		movfp	busyread, WREG		; fetch cursor position
		andlw	0x40				; clear all but row indicating bit
		iorlw	D'19'				; set to last visible location
		bsf		WREG, 7				; set bit to create load addr cmd
		call	SEND_CMD			; send to display
		return
NOWRAP
		movlw	CURS_LEFT			; load command to backup cursor
		call	SEND_CMD			; send the determined cmd to the display
		movlw	' '					; load space char to clear spot
		call	SEND_CHAR			; recursively call to send
		movlw	CURS_LEFT			; backup cursor again
		call	SEND_CMD			; send to display
		return

NOT_BACK
		movlw	0x0D				; test for carriage return
		cpfseq	temp
		goto	NOT_CR				; if not keep going
		; process carriage return
		movfp	busyread, WREG		; fetch current cursor position
		andlw	0x40				; clear all but row indicating bit
		bsf		WREG, 7				; set bit to create load addr cmd
		call	SEND_CMD
		return

NOT_CR
		movlw	0x0A				; test for line feed
		cpfseq	temp
		goto	NOT_LF				; if not keep going
		; process line feed and clear rest of line
		movfp	busyread, WREG		; fetch current cursor position
		btg		WREG, 6				; toggle row
		movwf	TEMP0				; save it
		bsf		WREG, 7				; set bit to create load addr cmd
		call	SEND_CMD			; toggle to other row on lcd
		movfp	busyread, WREG		; fetch curson position
		bcf		WREG, 6				; clear row indicating bit
		movwf	TEMP1				; save it
SPACES								; clear rest of new row
		movlw	18					; test for 19 or greater
		cpfsgt	TEMP1				; if cursor is in view skip
		goto	BACK_UP				; otherwise backup to original position
		movlw	' '					; load a space
		call	SEND_CHAR			; recursively call to send
		incf	TEMP1				; inc cursor position
		goto	SPACES
BACK_UP								; go back to original position
		movfp	TEMP0, WREG			; fetch old position
		bsf		WREG, 7				; set bit to create load addr cmd
		call	SEND_CMD
		return

NOT_LF
		; printable character
		swapf	temp, W				; get upper nibble into lower
		andlw	0x0F				; mask out D4-D7, clear RW
		movwf	LCD					; output upper data nibble
		bsf		LCD, RS				; set RS to data
		nop							; allow RS -> E > 140nS @ 33MHz
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz
		movfp	temp, WREG				; get lower nibble
		andlw	0x0F				; mask out D4-D7, clear RW
		movwf	LCD					; output lower data nibble
		bsf		LCD, RS				; set RS to data
		nop							; allow RS -> E > 140nS @ 33MHz
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz

		; test for wrap around
		movfp	busyread, WREG		; fetch last cursor position
		bcf		WREG, 6				; clear row indicating bit
		sublw	D'18'				; test for 19 or greater
		btfsc	ALUSTA, C			; if cursor is out of view skip
		return						; otherwise return
		; process carriage return and line feed
		movfp	busyread, WREG		; fetch current cursor position
		andlw	0x40				; clear all but row indicating bit
		btg		WREG, 6				; toggle row
		bsf		WREG, 7				; set bit to create load addr cmd
		call	SEND_CMD
		return
;
;*******************************************************************
;* SendCmd - Sends command in W to LCD                             *
;* This routine splits the command into the upper and lower        * 
;* nibbles and sends them to the LCD, upper nibble first.          *
;* The data is transmitted on the PORT<3:0> pins                   *
;*  Affects:  W and temp                                           *
;*******************************************************************
;
SEND_CMD
		movwf	temp				; save cmd to be sent
		movlb	LCD_BNK				; select SFR bank for LCD
		call	BUSY_CHECK			; wait for LCD ready
		swapf	temp, W				; get upper nibble into lower
		andlw	0x0F				; mask out D4-D7, clear RW and RS
		movwf	LCD					; output upper data nibble
		nop							; allow RS & RW -> E > 140nS @ 33MHz
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz
		movfp	temp, WREG			; get lower nibble
		andlw	0x0F				; mask out D4-D7, clear RW and RS
		movwf	LCD					; output lower data nibble
		nop							; allow RS & RW -> E > 140nS @ 33MHz
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz
		return
;
;*******************************************************************
;* This routine checks the busy flag, returns when not busy        *
;*  If a the routine checks for 
;*  Affects:  W and read value returned in busyread                *
;*******************************************************************
;
BUSY_CHECK

		call	SHORT_DELAY			; delay some

		movlw	0x0F				; set data pins to input
		iorwf	LCD_DDR				;
		bcf		LCD, RS				; clear for cmd mode
		bsf		LCD, RW				; set for read
		nop							; allow RW -> E > 140nS @ 33MHz
		bsf		LCD, E				; raise E
		nop							; allow data access > 320nS
		nop							; even at 33MHz
		swapf	LCD, W				; read upper nibble into W
		bcf		LCD, E				; lower E > 450nS @ 33MHz
		andlw	0xF0				; set lower nibble to 0
		movwf	busyread			; save in busyread
		nop							; allow > 1uS E cycle @ 33MHz
		bsf		LCD, E				; raise E
		nop							; allow data access > 320nS
		nop							; even at 33MHz
		movfp	LCD, WREG			; read lower nibble
		bcf		LCD, E				; lower E > 450nS @ 33MHz
		andlw	0x0F				; set upper nibble to 0
		iorwf	busyread, W			; merge nibbles
		btfsc	WREG, 7				; if busy don't skip
		goto	BUSY_CHECK			; check again
		movwf	busyread			; otherwise save read value in busyread
		movlw	0xF0				; set LCD port pins to output
		andwf	LCD_DDR				;
		return						; return with lcd present

;
; This routine takes the calculated times that the delay loop needs to
; be executed, based on the LCD_INIT_DELAY EQUate that includes the
; frequency of operation. 
;
LCD_DELAY   MOVLW   LCD_INIT_DELAY  ;
            MOVWF   TEMP0			; 
            CLRF    TEMP1			;
LOOP2       DECFSZ  TEMP1, F        ; Delay time = MSD * ((3 * 256) + 3) * Tcy
            GOTO    LOOP2           ; = 4.6mS - jea
            DECFSZ  TEMP0, F        ;
            GOTO    LOOP2           ;
            return

SHORT_DELAY
		clrf	WREG				; init WREG
		decfsz	WREG				; delay 3 * 256 * Tcy
		goto	$-1					; 
		return

;
; Initilize the LCD Display Module after power up
;
INIT_LCD
;
; Initialize port LCD to drive lcd module
;
		movlb	LCD_BNK				; select SFR bank for LCD
		bcf		LCD_DDR, E			; set E as an output
		bcf		LCD_DDR, RW			; set RW as an output
		bcf		LCD_DDR, RS			; set RS as an output
		movlw	0xF0				; 
		andwf	LCD_DDR				; set low nibble as data output
		clrf	LCD					; init all bits in LCD to 0
; delay > 15ms
		call	LCD_DELAY
		call	LCD_DELAY
		call	LCD_DELAY
		call	LCD_DELAY

		movlw	0x03				; Command for 8-bit interface
		movwf	LCD					; clearing RS & RW
		nop							; allow RS & RW -> E > 140nS @ 33MHz
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz

; delay > 4.1ms
		call	LCD_DELAY

		movlw	0x03				; Command for 8-bit interface
		movwf	LCD					; clearing RS & RW
		nop							; allow RS & RW -> E > 140nS @ 33MHz
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz

; delay > 100us
		call	LCD_DELAY

		movlw	0x03				; Command for 8-bit interface
		movwf	LCD					; clearing RS & RW
		nop							; allow RS & RW -> E > 140nS @ 33MHz
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz

; delay > 100us
		call	LCD_DELAY

		movlw	0x02				; Command for 4-bit interface
		movwf	LCD					; clearing RS & RW
		nop							; allow RS & RW -> E > 140nS @ 33MHz
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz

;
; Command sequence for 4-bit mode and 2 lines of 5x8 characters
;
		movlw	0x02				; 4-bit mode
		movwf	LCD					; output upper cmd nibble
		nop
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz
		movlw	0x08				; 2 line display
		movwf	LCD					; output lower cmd nibble
		nop							; allow > 1uS E cycle @ 33MHz
		bsf		LCD, E				; raise E
		nop							; 
		nop							; 
		nop							; 
		bcf		LCD, E				; lower E > 450nS @ 33MHz
;
; Busy Flag should be valid after this point
;
            MOVLW   DISP_OFF            ; Display Off
            CALL    SEND_CMD            ; Send This command to the Display Module
            MOVLW   CLR_DISP            ; Clear the Display
            CALL    SEND_CMD            ; Send This command to the Display Module
            MOVLW   ENTRY_INC           ; Set Entry Mode Inc., No shift
            CALL    SEND_CMD            ; Send This command to the Display Module
            MOVLW   DISP_ON             ; Display On, no Cursor
            CALL    SEND_CMD            ; Send This command to the Display Module
		movlw	0x0A				; load LF char
		call	SEND_CHAR			; send it to LCD
            RETURN



file: /Techref/piclist/andrewspicos/lcd.htm, 15KB, , updated: 2002/11/1 19:07, local time: 2017/10/22 05:08,
TOP NEW HELP FIND: 
54.167.202.184:LOG IN

 ©2017 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE! / 

<A HREF="http://www.piclist.com/techref/piclist/andrewspicos/lcd.htm"> piclist andrewspicos lcd</A>

After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.


Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?

  LCD Front Panel Set: $8.99!
- 2x16 LCD HD44780 controller
- 4 push buttons - 3 LEDs - 2x12 header
 

Welcome to www.piclist.com!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  .