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Pic18f4550 adc

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You can't use MOVLW to access what's in REG1... You must use " MOVF REG1, W "... If you use the first one the value of REG1 itself is loaded into W not it's contents.

RETLW means return literal... it must be a constant...

You don't need 16 bits to display characters... It's the table that has 16 bit addresses...
 
Hi Ian Rogers,

Can you please tell me where the 'MOVF REG1,W ... RETLW' should be placed? since it cannot be placed in the TEXT label, otherwise it will change the pointer address.

Below is the code as set earlier (ARROWS ARE USED TO INDICATE THE NEW CODING ):

OD EQU 60H
OE EQU 61H
OF EQU 62H
O5 EQU 65H
O6 EQU 63H
COUNT1 EQU 66H
COUNT2 EQU 64H
COUNT3 EQU 67H
table_temp EQU 68H
table EQU 69H
REG1 EQU 70H ;<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
;LCD DISPLAY PINOUTS
;1-GROUND, 2-VDD,
;3- VO(CONTRAST CONTROL)CONNECTED TO GROUND
;4-REGISTER SELECT = RE0 LOGIC 1 IF MICRO IS TRANSFERRING DATA
;LOGIC 0 IF MICRO IS TRANSFERRING A COMMAND
;5-READ/WRITE = RE1 LOGIC 1 TO READ FROM MODULE
; LOGIC 0 TO WRITE TO MODULE
;6-ENABLE LINE = RE2 DATA FROM MICRO TO MODULE IS TRANSFERRED FROM HIGH TO LOW OF THE ENABLE SIGNAL
; DATA READ FROM MODULE TO MICRO IS TRANSFERRD FROM LOW TO HI OF THE ENABLE SIGNAL
;7-DATA BIT 0 = NC
;8-DATA BIT 1 = NC
;9-DATA BIT 2 = NC
;10-DATA BIT 3 = NC
;11-DATA BIT 4 = RD4
;12-DATA BIT 5 = RD5
;13-DATA BIT 6 = RD6
;14-DATA BIT 7 = RD7
;15-BACK LIGHT +VE --CAN BE CONNECTED TO ANY PIN

ORG 0000H
;GOTO MAIN

;HIGH PRIORITY INTERRUPT VECTOR

ORG 0008H

;LOW PRIORITY INTERRUPT VECTOR

ORG 0018H

ORG 0020H

; INITIAIZATION

;MAIN PROGRAM

ORG 0050H

;INITIALIZATION

MOVLW 0FH ; INITIALIZE ALL PORTS AS DIGITAL INPUTS
MOVWF ADCON1

MOVLW 07H ;CONFIGURE COMPARATORS FOR DIGITAL INPUTS
MOVWF CMCON

CLRF TRISE
CLRF PORTE

MOVLW B'00000000' ;PORTD IS CONFIGURED AS OUTPUTS AND INPUTS
MOVWF TRISD
CLRF LATD
CLRF PORTD


MAIN

MOVLW B'00110001' ;ASSUMING THIS IS THE ADC RESULT <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
MOVWF REG1


CALL LONG_DELAY
CALL LONG_DELAY

FUNCTION_SET

BCF PORTE,0
BCF PORTE,1

movlw 38H
movwf PORTD
CALL PULSE_E
CALL SMALL_DELAY
CALL SMALL_DELAY ; I would initialise 0x33, 0x33, 0x38, 0xF, Ox1...

DISPLAY_ON
BCF PORTE,0
BCF PORTE,1
movlw 0FH
movwf PORTD
CALL PULSE_E
CALL SMALL_DELAY
CALL SMALL_DELAY

CLRF table

MESSAGE
MOVF table,W ; Increase message pointer
CALL TEXT
ANDLW 0FFH ; Check for NULL
BTFSC STATUS,Z
GOTO STOP ; Done
BSF PORTE,0
BCF PORTE,1
MOVWF PORTD ; Print
CALL PULSE_E
CALL SMALL_DELAY
CALL SMALL_DELAY
INCF table,F
GOTO MESSAGE

STOP
GOTO STOP

TEXT
MOVWF table_temp
BCF STATUS,C
RLCF table_temp,F
MOVLW HIGH(mess) ; Get High address
BTFSC STATUS, C ; If > 255
INCF WREG,W ;
MOVWF PCLATH
MOVLW LOW(mess) ; Get low address
ADDWF table_temp,W ; add message pointer
BTFSC STATUS,C ; if > 255
INCF PCLATH,F
MOVWF PCL
mess
RETLW REG1 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
RETLW 'E'
RETLW 'L'
RETLW 'L'
RETLW 'O'
RETLW 0H

PULSE_E
BSF PORTE,2
NOP
BCF PORTE,2
RETURN



LONG_DELAY
movlw D'2'
movwf COUNT1
movlw D'69'
movwf COUNT2
movlw D'169'
movwf COUNT3
loop
decfsz COUNT3
goto loop
decfsz COUNT2
goto loop
decfsz COUNT1
goto loop
RETURN



SMALL_DELAY
MOVLW .10
MOVWF COUNT2
LABEL2
CLRF COUNT1
LABEL1
DECFSZ COUNT1
GOTO LABEL1
DECFSZ COUNT2
GOTO LABEL2
RETURN

SEND

GOTO $

END
Click to expand...
 
Last edited:
You can't do that.... Lookup tables are stored in code... you need a variable... The idea for the lookup is to access fixed values..

Don't put REG1 in the table, you have to send the contents of REG1 directly to the screen....

1) Write the string / constants to the screen using the table.. ie "Value ="
2) Write the variables to the screen separately.. ie "1"

Remember that decimal values need to be converted to ascii characters first.... "1" = 0x31..


You really need to structure your code, so writing values to the LCD is easier..... When I get home I'll send you an example of what I mean..
 
Last edited:
hi adrian,
A would advise you not to use Labels for your Equates that start with a '0', use a more meaningful label name.

E.
 
Ohh finally i managed to do it.

After sending all characters to the display, i sent the pointer to another routine where i used the below coding to display the value:

SEND_A2D_RESULT ;label
MOVFF REG1,PORTD ;move the value of the A2C (reg1) to data pins
CALL PULSE_E ;write comand to LCD
END

Below is the fill coding (arrows included to mark new coding):

Code: 
	COUNT1        EQU 60H
	COUNT2        EQU 61H
    COUNT3        EQU 62H
	TABLE_TEMP    EQU 63H
	TABLE         EQU 64H
REG 1 EQU 65H   ;<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

 
	ORG 0000H


	;INITIALIZATION
 
	MOVLW 0FH			; INITIALIZE ALL PORTS AS DIGITAL INPUTS
	MOVWF ADCON1
 
	MOVLW 07H			;CONFIGURE COMPARATORS FOR DIGITAL INPUTS
	MOVWF CMCON	
 
	CLRF TRISE
	CLRF PORTE
 
	MOVLW B'00000000'	;PORTD IS CONFIGURED AS OUTPUTS AND INPUTS
	MOVWF TRISD 
	CLRF LATD
	CLRF PORTD
 
 
MAIN


MOVLW B'00110001'  ;<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
MOVWF REG1
 
	CALL LONG_DELAY
 
FUNCTION_SET
 
	BCF PORTE,0		
	BCF PORTE,1		
 
	MOVLW	38H
	MOVWF	PORTD
	CALL PULSE_E
	CALL SMALL_DELAY	; I would initialise 0x33, 0x33, 0x38, 0xF, Ox1...
 
DISPLAY_ON
	BCF PORTE,0		
	BCF PORTE,1	
	MOVLW	0CH
	MOVWF	PORTD
	CALL PULSE_E
	CALL SMALL_DELAY
 
	CLRF TABLE
 
MESSAGE
	MOVF TABLE,W		; Increase message pointer
	CALL TEXT
	ANDLW 0FFH		; Check for NULL
	BTFSC STATUS,Z
	GOTO SEND_A2D_RESULT   ;<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
	BSF PORTE,0		
	BCF PORTE,1	
	MOVWF PORTD		; Print
	CALL PULSE_E
	CALL SMALL_DELAY
	INCF TABLE,F
	GOTO MESSAGE
 
 
TEXT
	MOVWF TABLE_TEMP
	BCF STATUS,C
	RLCF TABLE_TEMP,F				
	MOVLW HIGH(mess) 	; Get High address
	BTFSC STATUS, C		; If > 255				
	INCF WREG,W		;			
	MOVWF PCLATH
	MOVLW LOW(mess)	 ; Get low address			
	ADDWF TABLE_TEMP,W	; add message pointer
	BTFSC STATUS,C		; if > 255			
	INCF PCLATH,F
	MOVWF PCL				
mess 
	RETLW 'I'
	RETLW 't'
	RETLW 's'
	RETLW ' '
    RETLW 'W'
    RETLW 'o'
	RETLW 'r'
	RETLW 'k'
	RETLW 'i'
	RETLW 'n'
    RETLW 'g'
	RETLW ' '
	RETLW 'X'
    RETLW 'D'
	RETLW 0H

SEND_A2D_RESULT   ;<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
MOVFF REG1,PORTD     
CALL PULSE_E
GOTO SEND
 
PULSE_E
	BSF PORTE,2
	NOP
	BCF PORTE,2
	RETURN
 
 
 
LONG_DELAY
	MOVLW	.2
	MOVWF	COUNT1
    MOVLW	.69
	MOVWF	COUNT2
	MOVLW	.169
	MOVWF	COUNT3
loop		
	DECFSZ	COUNT3
	GOTO	loop
	DECFSZ	COUNT2
	GOTO	loop
	DECFSZ	COUNT1
	GOTO	loop
	RETURN
 
 
 
SMALL_DELAY
	MOVLW .10
	MOVWF COUNT2
LABEL2
	CLRF COUNT1
LABEL1
	DECFSZ COUNT1
	GOTO LABEL1
	DECFSZ COUNT2
	GOTO LABEL2
	RETURN
 
SEND
 
GOTO $		; THIS WILL STOP THE MICRO FROM STARTING TO EXECUTRE THE PROGRAME AGAIN EVEN AFTER
			; SENDING IT TO THE END DIRECTIVE
 
END


Is it structured correctly, or is everything messed up??

Thanks
 
Hi ericgibbs,

Yes the program was giving me errors because of that. I used those labels temporary.

Apart from them, is the coding in post number 107 structured/organized correctly?

Edit: By the way, is there a limit of how many registers can be used? when declaring them (ex: reg1 equ 60h ... reg2 equ 61h) is there a limit?
and is it ok to used the same registers for different routines (example use the same registers for different delay routines)?

Thanks
 
Last edited:
I live in Mosta, but we have a summer residence in Qawra near the Suncrest Hotel. Yea Malta is definitely a nice place to live in, but i do hate the extreme heat during summer time :)
 
Last edited:
Tell me about it..... Once I couldn't go outside... 115 degrees..... Apparently in Turkey, in the same year, people actual died from the heat.

Anyway I digress... I will post some code tonight to help you on your way...
 
Here you go.... A little more structured plus their is a BCD routine for 8 bit decimal to help to write to the LCD...

Code: 
;	USE OF TABLES
;	LCD DRIVER
;	DETERMINING THE LOATION WHERE WE WANT THE WORDS TO START
;	USING A LOOP TO DIREGARD THE FIRST 4 LTTERS AND START OUTPUTING FROM THE FIFTH LETTER
;	WRITING IN LOWER ROW
;	CONVERTING FROM 8 BIT TO 4 BIT
	LIST P=18F4550, F=INHX32	;directive to define processor
	#include <P18F4550.INC>	;processor specific variable definitions
		
	CONFIG   FOSC = HSPLL_HS        ; XT oscillator, PLL enabled, XT used by USB 
;	CONFIG   PLLDIV = 5		; No prescale (20 MHz oscillator divide by 5 drives PLL directly)
	CONFIG   PLLDIV = 1		; No prescale (4 MHz oscillator) 

	CONFIG   CPUDIV = OSC1_PLL2	; [OSC1/OSC2 Src: /1][96 MHz PLL Src: /2]

;	PLL Prescaler Selection bits:
;	PLLDIV = 1           No prescale (4 MHz oscillator input drives PLL directly)
;	PLLDIV = 2           Divide by 2 (8 MHz oscillator input)
;	PLLDIV = 3           Divide by 3 (12 MHz oscillator input)
;	PLLDIV = 4           Divide by 4 (16 MHz oscillator input)
;	PLLDIV = 5           Divide by 5 (20 MHz oscillator input)
;	PLLDIV = 6           Divide by 6 (24 MHz oscillator input)
;	PLLDIV = 10          Divide by 10 (40 MHz oscillator input)
;	PLLDIV = 12          Divide by 12 (48 MHz oscillator input)
;
;	CPU System Clock Postscaler:
;	CPUDIV = OSC1_PLL2   [OSC1/OSC2 Src: /1][96 MHz PLL Src: /2]
;	CPUDIV = OSC2_PLL3   [OSC1/OSC2 Src: /2][96 MHz PLL Src: /3]
;	CPUDIV = OSC3_PLL4   [OSC1/OSC2 Src: /3][96 MHz PLL Src: /4]
;	CPUDIV = OSC4_PLL6   [OSC1/OSC2 Src: /4][96 MHz PLL Src: /6]

	CONFIG   USBDIV = 2  			; USB clock source comes from the 96 MHz PLL divided by 2
;	CONFIG   FCMEM = OFF			; Fail-Safe Clock Monitor disabled
	CONFIG   IESO = OFF 			; Oscillator Switchover mode disabled	
;	CONFIG   WDT = OFF			; HW Disabled - SW Controlled
	

;----- CONFIG2H Options --------------------------------------------------
	CONFIG WDT = OFF			    ; HW Disabled - SW Controlled
;	CONFIG WDT = ON           			    ; HW Enabled - SW Disabled

	;WDTPS_1_2H          EQU  H'E1'    ; 1:1
	;_WDTPS_2_2H          EQU  H'E3'    ; 1:2
	;_WDTPS_4_2H          EQU  H'E5'    ; 1:4
	;_WDTPS_8_2H          EQU  H'E7'    ; 1:8
	;_WDTPS_16_2H         EQU  H'E9'    ; 1:16
	;_WDTPS_32_2H         EQU  H'EB'    ; 1:32
	;_WDTPS_64_2H         EQU  H'ED'    ; 1:64
	;_WDTPS_128_2H        EQU  H'EF'    ; 1:128
	;_WDTPS_256_2H        EQU  H'F1'    ; 1:256
	;_WDTPS_512_2H        EQU  H'F3'    ; 1:512
	;_WDTPS_1024_2H       EQU  H'F5'    ; 1:1024
	;_WDTPS_2048_2H       EQU  H'F7'    ; 1:2048
	;_WDTPS_4096_2H       EQU  H'F9'    ; 1:4096
	;_WDTPS_8192_2H       EQU  H'FB'    ; 1:8192
	;_WDTPS_16384_2H      EQU  H'FD'    ; 1:16384
	CONFIG WDTPS = 32768		    ; 1:32768

	CONFIG   PWRT = OFF  			; PWRT DISabled
	;CONFIG  BOR = OFF 				; Brown-out Reset disabled in hardware and software
	;CONFIG  BOR = SOFT             ; Brown-out Reset enabled and controlled by software (SBOREN is enabled)
	;CONFIG  BOR = ON_ACTIVE        ; Brown-out Reset enabled in hardware only and disabled in Sleep mode (SBOREN is disabled)
	;CONFIG  BOR = ON               ; Brown-out Reset enabled in hardware only (SBOREN is disabled)

	;CONFIG  BORV = 0  			    ; Maximum setting
	;CONFIG  BORV = 1    			; 
	;CONFIG  BORV = 2    			; 
	CONFIG  BORV = 3      			; Minimum setting

	;CONFIG  VREGEN = OFF           ; USB voltage regulator disabled
	CONFIG  VREGEN = ON           ; USB voltage regulator enabled
	
	CONFIG   MCLRE = ON				; MCLR pin enabled; RE3 input pin disabled
	CONFIG	 LPT1OSC = OFF          ; Timer1 configured for higher power operation
	;CONFIG  LPT1OSC = ON            ; Timer1 configured for low-power operation

	CONFIG   PBADEN = OFF          ; PORTB<4:0> pins are configured as digital I/O on Reset
	;CONFIG   PBADEN = ON            ; PORTB<4:0> pins are configured as analog input channels on Reset	
	
	CONFIG   CCP2MX = OFF           ; CCP2 input/output is multiplexed with RB3
;	CONFIG   CCP2MX = ON           ; CCP2 input/output is multiplexed with RC1CCP2MX = OFF

;	CONFIG	 STVREN = OFF           ; Stack full/underflow will not cause Reset
	CONFIG   STVREN = ON           ; Stack full/underflow will cause Reset 
	
	CONFIG   LVP = OFF              ; Single-Supply ICSP disabled
;	CONFIG   LVP = ON              ; Single-Supply ICSP enabled
	
	CONFIG  ICPRT = OFF             ; ICPORT disabled
;	CONFIG  ICPRT = ON             ; ICPORT enabled

	CONFIG  XINST = OFF            ; Instruction set extension and Indexed Addressing mode disabled (Legacy mode)
;	CONFIG  XINST = ON              ; Instruction set extension and Indexed Addressing mode enabled

;	CONFIG  DEBUG = ON              ; Background debugger enabled, RB6 and RB7 are dedicated to In-Circuit Debug
	CONFIG  DEBUG = OFF             ; Background debugger disabled, RB6 and RB7 configured as general purpose I/O pins

	;CONFIG CP0 = ON        	; Block 0 (000800-001FFFh) code-protected
	CONFIG  CP0 = OFF               ; Block 0 (000800-001FFFh) not code-protected

;	CONFIG  CP1 = ON                ; Block 1 (002000-003FFFh) code-protected
	CONFIG  CP1 = OFF               ; Block 1 (002000-003FFFh) not code-protected

;	CONFIG  CP2 = ON                ; Block 2 (004000-005FFFh) code-protected
	CONFIG  CP2 = OFF               ; Block 2 (004000-005FFFh) not code-protected

;----- CONFIG5H Options --------------------------------------------------
;	CONFIG  CPB = ON                ; Boot block (000000-0007FFh) code-protected
	CONFIG  CPB = OFF               ; Boot block (000000-0007FFh) not code-protected

;	CONFIG  CPD = ON                ; Data EEPROM code-protected
	CONFIG  CPD = OFF               ; Data EEPROM not code-protected

;----- CONFIG6L Options --------------------------------------------------
	;CONFIG  WRT0 = ON              ; Block 0 (000800-001FFFh) write-protected
	CONFIG  WRT0 = OFF              ; Block 0 (000800-001FFFh) not write-protected

;	CONFIG  WRT1 = ON               ; Block 1 (002000-003FFFh) write-protected
	CONFIG  WRT1 = OFF              ; Block 1 (002000-003FFFh) not write-protected

;	CONFIG  WRT2 = ON               ; Block 2 (004000-005FFFh) write-protected
	CONFIG  WRT2 = OFF              ; Block 2 (004000-005FFFh) not write-protected

;----- CONFIG6H Options --------------------------------------------------
	CONFIG  WRTB = ON               ; Configuration registers (300000-3000FFh) write-protected
	;CONFIG  WRTB = OFF             ; Configuration registers (300000-3000FFh) not write-protected

	;CONFIG  WRTC = ON       	; Boot block (000000-0007FFh) write-protected
	CONFIG  WRTC = OFF  		; Boot block (000000-0007FFh) not write-protected

	;CONFIG  WRTD = ON              ; Data EEPROM write-protected
	CONFIG  WRTD = OFF              ; Data EEPROM not write-protected

;----- CONFIG7L Options --------------------------------------------------
	;CONFIG  EBTR0 = ON   		; Block 0 (000800-001FFFh) protected from table reads executed in other blocks
	CONFIG  EBTR0 = OFF		; Block 0 (000800-001FFFh) not protected from table reads executed in other blocks

	;CONFIG  EBTR1 = ON             ; Block 1 (002000-003FFFh) protected from table reads executed in other blocks
	CONFIG  EBTR1 = OFF             ; Block 1 (002000-003FFFh) not protected from table reads executed in other blocks

	;CONFIG  EBTR2 = ON  		; Block 2 (004000-005FFFh) protected from table reads executed in other blocks
	CONFIG  EBTR2 = OFF   		; Block 2 (004000-005FFFh) not protected from table reads executed in other blocks

;----- CONFIG7H Options --------------------------------------------------
	;CONFIG  EBTRB = ON 		; Boot block (000000-0007FFh) protected from table reads executed in other blocks
	CONFIG  EBTRB = OFF             ; Boot block (000000-0007FFh) not protected from table reads executed in other blocks


; 	PRIMARY CLOCK IS A 4MHZ CRYSTAL CONNECTED TO PINS 13/14
; 	PRESCALING TO 48MHZ CORE SPEED AND 48MHZ USB ENGINE SPEED

;	DECLERATIONS MUST BE PLACED IN LOWER HALF OF ACCESS BANK (160 GPRs) BECAUSE THE HIGHER
;	HALF OF ACCESS BANK IS COMPOSED OF SFRs. RANGE OF LOWER HALF IS FROM 60H - FFH.
	OD 		EQU 60H
	OE 		EQU 61H
	OF 		EQU 62H
	O5 		EQU 65H
	O6 		EQU 63H
	COUNT1 		EQU 66H
	COUNT2 		EQU 64H
    	COUNT3 		EQU 67H
	table_temp 	EQU 68H
	table 		EQU 69H
	REG1 		EQU 6AH

	ONES		EQU 6BH
	TENS 		EQU 6CH
	HUND 		EQU 6DH
	
	NUMBL 		EQU 6EH
	NUMBH 		EQU 6FH
	TMP 		EQU 70H


;	LCD DISPLAY PINOUTS
;	1-GROUND, 2-VDD,
;	3- VO(CONTRAST CONTROL)CONNECTED TO GROUND
;	4-REGISTER SELECT = RE0 LOGIC 1 IF MICRO IS TRANSFERRING DATA
;		LOGIC 0 IF MICRO IS TRANSFERRING A COMMAND	
;	5-READ/WRITE = RE1 LOGIC 1 TO READ FROM MODULE
;		LOGIC 0 TO WRITE TO MODULE
;	6-ENABLE LINE = RE2 DATA FROM MICRO TO MODULE IS TRANSFERRED FROM HIGH TO LOW OF THE ENABLE SIGNAL 
;               DATA READ FROM MODULE TO MICRO IS TRANSFERRD FROM LOW TO HI OF THE ENABLE SIGNAL
;	7-DATA BIT 0 = NC
;	8-DATA BIT 1 = NC
;	9-DATA BIT 2 = NC
;	10-DATA BIT 3 = NC
;	11-DATA BIT 4 = RD4
;	12-DATA BIT 5 = RD5
;	13-DATA BIT 6 = RD6
;	14-DATA BIT 7 = RD7
;	15-BACK LIGHT +VE --CAN BE CONNECTED TO ANY PIN

	ORG 	0000H
;	GOTO 	MAIN

;HIGH PRIORITY INTERRUPT VECTOR

	ORG 	0008H

;LOW PRIORITY INTERRUPT VECTOR

	ORG 	0018H

	ORG 	0020H
  
;INITIAIZATION

;MAIN PROGRAM

	ORG 	0050H

;INITIALIZATION

	MOVLW 	0FH			; INITIALIZE ALL PORTS AS DIGITAL INPUTS
	MOVWF 	ADCON1

	MOVLW 	07H			;CONFIGURE COMPARATORS FOR DIGITAL INPUTS
	MOVWF 	CMCON	

	CLRF 	TRISE
	CLRF 	PORTE

	MOVLW 	B'00000000'		;PORTD IS CONFIGURED AS OUTPUTS AND INPUTS
	MOVWF 	TRISD 
	CLRF 	LATD
	CLRF 	PORTD

MAIN
	CALL 	LONG_DELAY
	CALL 	LONG_DELAY
	MOVLW 	.154			; Could be adc input
	MOVWF 	REG1

;INIT DISPLAY
	movlw	33H
	CALL 	LCDCOMMAND
	CALL 	LONG_DELAY

	movlw	38H
	CALL 	LCDCOMMAND
	CALL 	SMALL_DELAY

	movlw	0FH
	CALL 	LCDCOMMAND
	CALL 	SMALL_DELAY		

	movlw	01H
	CALL 	LCDCOMMAND
	CALL 	SMALL_DELAY	; I would initialise 0x33, 0x33, 0x38, 0xF, Ox1...

	CLRF 	table

MESSAGE
	MOVF 	table,W		; Increase message pointer
	CALL 	TEXT
	ANDLW 	0FFH		; Check for NULL
	BTFSC 	STATUS,Z
	GOTO 	MESSFIN		; Done
	CALL 	LCDDATA
	INCF 	table,F
	GOTO 	MESSAGE
MESSFIN	
	MOVF 	REG1,W
	MOVWF	NUMBL
	CALL	BIN2BCD

	MOVF	TENS,W
	ANDLW	0FH
	ADDLW	30H
	CALL 	LCDDATA
	CALL 	SMALL_DELAY
	SWAPF	ONES,W
	ANDLW	0FH
	ADDLW	30H
	CALL 	LCDDATA
	CALL 	SMALL_DELAY
	MOVF	ONES,W
	ANDLW	0FH
	ADDLW	30H
	CALL 	LCDDATA
	CALL 	SMALL_DELAY

STOP
	GOTO STOP

LCDDATA
	BSF 	PORTE,0		
	BCF 	PORTE,1	
	movwf	PORTD
	CALL 	PULSE_E
	CALL 	SMALL_DELAY
	CALL 	SMALL_DELAY
	RETURN

LCDCOMMAND
	BCF 	PORTE,0		
	BCF 	PORTE,1	
	movwf	PORTD
	CALL 	PULSE_E
	CALL 	SMALL_DELAY
	CALL 	SMALL_DELAY
	RETURN
TEXT
	MOVWF	table_temp
	BCF	STATUS,C
	RLCF	table_temp,F				
	MOVLW	HIGH(message) 	; Get High address
	BTFSC	STATUS, C		; If > 255				
	INCF	WREG,W		;			
	MOVWF	PCLATH
	MOVLW	LOW(message)	; Get low address			
	ADDWF	table_temp,W	; add message pointer
	BTFSC	STATUS,C		; if > 255			
	INCF	PCLATH,F
	MOVWF	PCL				
message 
	RETLW 'V'
	RETLW 'A'
	RETLW 'L'
	RETLW 'U'
	RETLW 'E'
	RETLW ' '
	RETLW '='
	RETLW ' '
	RETLW 0H
PULSE_E
	BSF	PORTE,2
	NOP
	BCF	PORTE,2
	RETURN
BIN2BCD
	MOVLW	D'5'
	MOVWF	COUNT1
 	CLRF	ONES
	CLRF	TENS

	RLCF	NUMBL,F
	RLCF	ONES,F
	RLCF	NUMBL,F
	RLCF	ONES,F
	RLCF	NUMBL,F
	RLCF	ONES,F
REPEAT
        MOVF	ONES,W
        ADDLW	0x33
	MOVWF	TMP
        MOVF	ONES,W
	BTFSC	TMP,3
	ADDLW	0x03
	BTFSC	TMP,7
	ADDLW	0x30
	MOVWF	ONES
 	RLCF	NUMBL,F
	RLCF	ONES,F
	RLCF	TENS,F
	DECFSZ	COUNT1,F
        GOTO    REPEAT
	RETURN

LONG_DELAY
	movlw	D'2'
	movwf	COUNT1
	movlw	D'69'
	movwf	COUNT2
	movlw	D'169'
	movwf	COUNT3
loop		
	decfsz	COUNT3
	goto	loop
	decfsz	COUNT2
	goto	loop
	decfsz	COUNT1
	goto	loop
	RETURN

SMALL_DELAY
	MOVLW	.10
	MOVWF	COUNT2
LABEL2
	CLRF	COUNT1
LABEL1
	DECFSZ	COUNT1
	GOTO	LABEL1
	DECFSZ	COUNT2
	GOTO	LABEL2
	RETURN
SEND

GOTO $		; THIS WILL STOP THE MICRO FROM STARTING TO EXECUTRE THE PROGRAME AGAIN EVEN AFTER
			; SENDING IT TO THE END DIRECTIVE
END
You may need me to comment on the added components....
 
Last edited:
Hi Ian Rogers,

Thanks for that. Really appreciate it :)

I have 3 question:

1) What is the difference between 5x7 DOT FORMAT and 5x10 DOT FORMAT ??

2) I am using the LCD in the link below which is 16*4. How do i initialize it as a 4 line display? since in the datasheet i can only see up to 2 line setup.

**broken link removed**

3) I want the project to be low in power consumption as possible. Is it a good idea if i connect a PIR sensor (link below) with the backlight pin??
(this will be done so that when the room is empty the backlight will turn off, therefore consuming less power)

**broken link removed**

Thanks
 
Last edited:
1) On the lcd there are three lines (see the picture )... Basically it enables that... ( never seen any use it though )

2) All displays are configured for two line.... The second line is a continuation of line 1 ... 0x90 ( 0x80 + 16 characters ) and the forth is a continuation of the third line.
the only difference is the amount of CGram available.

3) Yes.... I have a pin that can turn on the back light..... Also use 3/4 of the current... If the backlight is 100mA then use 75mA.. you will still see clearly and the backlight will last much longer.


Another way is to have the backlight off.. when the user presses a button it comes on for about 2/3 minutes then goes off again.
 
Last edited:
Hi,

I want to include a menu on the LCD where one can change the system's setting (example turn off buzzer, set system to operate manually or automatically etc.).

Can the chosen settings be saved in registers? or is there another way how to do this?

I was going to use the below coding setup:

display: Turn buzzer on?
'Yes' button pressed
BSF MENU_REG1, 0
...
...
...
BTFSC MENU_REG1, 0
GOTO BUZZER_ON
GOTO BLA_BLA
 
You no you can use select case in asm

Code: 
movlw "G"
    xorwf SCRATCH,w
    bz label1
 
    movlw "R"
    xorwf SCRATCH,w
    bz label2
 
    movlw "Z"
    xorwf SCRATCH,w
    bz label3
 
Hi, is SCRATCH a register that i have to declare? and what is the routine doing exactly because i cannot understand it.

So you don't suggest using registers to save the settings ?

Thanks.
 
Another question: Can i use the CALL instruction every time i want to write on the LCD (as below):
The reason i want it this way is to make the main coding neater.

Code: 
Main program
....
...
...
call lcd_home_page
...
...
...

lcd_home_page
display: Home characters 
return

Instead of:

Code: 
Main program
....
...
...
display: Home characters 
...
...
...
 
Last edited:
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