kvrajasekar
- 6th December 2008, 15:54
Hi,
I am using CDM16216b LCD to interface with 16f72.I am trying to display characters on lcd,but i didnt get anything on LCD.
Please kindly reply me,where i am going wrong.
list p=16f72 ;PIC16f72 is the target processor
INCLUDE "P16f72.INC"
;------------------------------------------------------------------------------------
; PORTA control bits
__CONFIG _PWRTE_ON & _XT_OSC & _WDT_OFF ; configuration switches
#DEFINE LCD_RS PORTA, 0 ; RA0 is RS line of LCD
#DEFINE LCD_E PORTA, 1 ; RA1 is E line of LCD
; RC0-RC3 are D4-D7 of LCD
Temp equ 0x20
delay1 equ 0x21
org 0x00
goto start
;------------------------------------------------------------------------------------
start
bsf STATUS, RP0 ; Bank1
errorlevel 1,-302 ; Don't warn me about bank 1
movlw b'00000000' ; Defining input and output pins
movwf TRISA ; Writing to TRISA register
movlw b'00000000' ; Defining input and output pins
movwf TRISB ; Writing to TRISB register 1-input,0-output
movlw b'00000000'
movwf TRISC
movlw b'10000110' ; TMR0,prescaler-128
movwf OPTION_REG
movlw 0x07
movwf ADCON1
bcf STATUS, RP0 ; Bank0
clrf PORTA ; potra,portb initially set to low
clrf PORTB
clrf PORTC
call lcd_init
bsf PORTA,5 ; Buzzer
call delay_0.5s
bcf PORTA,5
call disp_main
movlw 0xC1
call disp_cmd
btfsc PORTB,4 ;UPS RDY
call disp_ups
lcd_init
movlw 0x28 ; 4 bit, 2 Line, 5x7 font
call disp_cmd
call delay
; movlw 0x10 ; display shift off
; call disp_cmd
; call delay
movlw 0x0E ; increment cursor
call disp_cmd
call delay
movlw 0x01 ; Clear the Display RAM
call disp_cmd
call delay ; Note, Can take up to 4.1 msecs
movlw 0x06 ; move the cursor to begining
call disp_cmd
call delay
; movlw 0x0C ; display on cursor off
; call disp_cmd
; call delay
return
delay
movlw d'236' ;2.5ms delay
movwf TMR0
loop1 btfss INTCON,2
goto loop1
clrf INTCON ; if overflow occur,clear INTCON
return
d
;------------------------------------------------------------------------------------
;Display command for 4 bit LCD
disp_cmd ; Send the Instruction to the LCD
movwf Temp ; Save the Temporary Value
swapf Temp, w ; Send the High Nybble
bcf LCD_RS ; RS = 0
call nibbleout
movf Temp, w ; Send the Low Nybble
bcf LCD_RS
call nibbleout
return
;------------------------------------------------------------------------------------
;sending ASCII character to LCD
disp_write
; addlw '0' ; Send nbr as ASCII character ; Send the Character to the LCD
movwf Temp ; Save the Temporary Value
swapf Temp, w ; the High Nybble
bsf LCD_RS ; RS = 1
call nibbleout
movf Temp, w ; Send the Low Nybble
bsf LCD_RS
call nibbleout
return
;------------------------------------------------------------------------------------
;sending lower and upper nibble
nibbleout ; Send a nibble to the LCD
movwf PORTC
bsf LCD_E
call delay
bcf LCD_E
nop
nop
return
disp_main
movlw 'M' ; output 'MAIN'
call disp_write
movlw 'A'
call disp_write
movlw 'I'
call disp_write
movlw 'N'
call disp_write
movlw ' '
call disp_write
movlw 'N'
call disp_write
movlw 'O'
call disp_write
movlw 'R'
call disp_write
return
end
I am using CDM16216b LCD to interface with 16f72.I am trying to display characters on lcd,but i didnt get anything on LCD.
Please kindly reply me,where i am going wrong.
list p=16f72 ;PIC16f72 is the target processor
INCLUDE "P16f72.INC"
;------------------------------------------------------------------------------------
; PORTA control bits
__CONFIG _PWRTE_ON & _XT_OSC & _WDT_OFF ; configuration switches
#DEFINE LCD_RS PORTA, 0 ; RA0 is RS line of LCD
#DEFINE LCD_E PORTA, 1 ; RA1 is E line of LCD
; RC0-RC3 are D4-D7 of LCD
Temp equ 0x20
delay1 equ 0x21
org 0x00
goto start
;------------------------------------------------------------------------------------
start
bsf STATUS, RP0 ; Bank1
errorlevel 1,-302 ; Don't warn me about bank 1
movlw b'00000000' ; Defining input and output pins
movwf TRISA ; Writing to TRISA register
movlw b'00000000' ; Defining input and output pins
movwf TRISB ; Writing to TRISB register 1-input,0-output
movlw b'00000000'
movwf TRISC
movlw b'10000110' ; TMR0,prescaler-128
movwf OPTION_REG
movlw 0x07
movwf ADCON1
bcf STATUS, RP0 ; Bank0
clrf PORTA ; potra,portb initially set to low
clrf PORTB
clrf PORTC
call lcd_init
bsf PORTA,5 ; Buzzer
call delay_0.5s
bcf PORTA,5
call disp_main
movlw 0xC1
call disp_cmd
btfsc PORTB,4 ;UPS RDY
call disp_ups
lcd_init
movlw 0x28 ; 4 bit, 2 Line, 5x7 font
call disp_cmd
call delay
; movlw 0x10 ; display shift off
; call disp_cmd
; call delay
movlw 0x0E ; increment cursor
call disp_cmd
call delay
movlw 0x01 ; Clear the Display RAM
call disp_cmd
call delay ; Note, Can take up to 4.1 msecs
movlw 0x06 ; move the cursor to begining
call disp_cmd
call delay
; movlw 0x0C ; display on cursor off
; call disp_cmd
; call delay
return
delay
movlw d'236' ;2.5ms delay
movwf TMR0
loop1 btfss INTCON,2
goto loop1
clrf INTCON ; if overflow occur,clear INTCON
return
d
;------------------------------------------------------------------------------------
;Display command for 4 bit LCD
disp_cmd ; Send the Instruction to the LCD
movwf Temp ; Save the Temporary Value
swapf Temp, w ; Send the High Nybble
bcf LCD_RS ; RS = 0
call nibbleout
movf Temp, w ; Send the Low Nybble
bcf LCD_RS
call nibbleout
return
;------------------------------------------------------------------------------------
;sending ASCII character to LCD
disp_write
; addlw '0' ; Send nbr as ASCII character ; Send the Character to the LCD
movwf Temp ; Save the Temporary Value
swapf Temp, w ; the High Nybble
bsf LCD_RS ; RS = 1
call nibbleout
movf Temp, w ; Send the Low Nybble
bsf LCD_RS
call nibbleout
return
;------------------------------------------------------------------------------------
;sending lower and upper nibble
nibbleout ; Send a nibble to the LCD
movwf PORTC
bsf LCD_E
call delay
bcf LCD_E
nop
nop
return
disp_main
movlw 'M' ; output 'MAIN'
call disp_write
movlw 'A'
call disp_write
movlw 'I'
call disp_write
movlw 'N'
call disp_write
movlw ' '
call disp_write
movlw 'N'
call disp_write
movlw 'O'
call disp_write
movlw 'R'
call disp_write
return
end