problem with PIC16F877+LCD display - Page 2 - Electronic Circuits Projects Diagrams Free

**Nigel Goodwin** · 9th June 2007, 09:06 AM

Quote:

Originally Posted by Pommie

I assumed everyone was talking tongue in cheek and joking around.
If you see movlw 0x9 (only 4 bits) do you assume it will add a trailing zero and load 0x90 into W.
When I posted above, "It would of course take B'1' as 128." I was joking.
I don't think I have ever come across a situation where you add trailing zeroes.

I'm VERY distrustful

meera83 · 11th June 2007, 02:36 AM

Help!Help! i really don't know what can i do with the source code..

I had make some changing to Nigel's LCD tutorial according to my port pin,
from PICDEM 2 PLUS circuit shcematic, the port pin
RA1 - E
RA2 - RW
RA3 - RS

DB4 - RD0
DB5 - RD1
DB6 - RD2
DB7 - RD3

but the LCD still don't have any respond..

meera83 · 11th June 2007, 02:40 AM

Quote:

Originally Posted by meera83

Help!Help! i really don't know what can i do with the source code..

I had make some changing to Nigel's LCD tutorial according to my port pin,
from PICDEM 2 PLUS circuit shcematic, the port pin
RA1 - E
RA2 - RW
RA3 - RS

DB4 - RD0
DB5 - RD1
DB6 - RD2
DB7 - RD3

but the LCD still don't have any respond..

this is the changing code that i program in PIC..

meera83 · 11th June 2007, 02:43 AM

what's mean by this code?

LCD_RS Equ 0x04 ;LCD handshake lines
LCD_RW Equ 0x06
LCD_E Equ 0x07

if my port pin connection is like
RA1 - E
RA2 - RW
RA3 - RS

DB4 - RD0
DB5 - RD1
DB6 - RD2
DB7 - RD3

then what location should i write??

thanks..

bananasiong · 11th June 2007, 02:44 AM

Quote:

Originally Posted by meera83

this is the changing code that i program in PIC..

Your attachment is only this:

Code:

	list      p=16f877            ; list directive to define processor
	#include <p16f877.inc>        ; processor specific variable definitions
	
	__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _LP_OSC & _WRT_ENABLE_OFF & _LVP_OFF & _DEBUG_OFF & _CPD_OFF 

; '__CONFIG' directive is used to embed configuration data within .asm file.
; The labels following the directive are located in the respective .inc file.
; See respective data sheet for additional information on configur

bananasiong · 11th June 2007, 02:49 AM

Quote:

Originally Posted by meera83

what's mean by this code?

LCD_RS Equ 0x04 ;LCD handshake lines
LCD_RW Equ 0x06
LCD_E Equ 0x07

Define LCD_RS as bit 4 of the port, RW as bit 6 and E as bit 7.
So during programming, when you want to set RS, you simply

Code:

bsf PORTA, LCD_RS

Quote:

if my port pin connection is like
RA1 - E
RA2 - RW
RA3 - RS

DB4 - RD0
DB5 - RD1
DB6 - RD2
DB7 - RD3

then what location should i write??

You can define them as:

Code:

LCD_RS		Equ	0x03		
LCD_RW		Equ	0x02
LCD_E		Equ	0x01

Depends on which port and which pin are you connecting them to.
You use portD for the data bits, just change it in the code.

meera83 · 11th June 2007, 03:05 AM

Quote:

Originally Posted by bananasiong

Your attachment is only this:

Code:

	list      p=16f877            ; list directive to define processor
	#include <p16f877.inc>        ; processor specific variable definitions
	
	__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _LP_OSC & _WRT_ENABLE_OFF & _LVP_OFF & _DEBUG_OFF & _CPD_OFF 

; '__CONFIG' directive is used to embed configuration data within .asm file.
; The labels following the directive are located in the respective .inc file.
; See respective data sheet for additional information on configur

i had re-attach the file again..

i think the port pin that i define is right, but i didn't understand that why the LCD still no respond...

bananasiong · 11th June 2007, 03:21 AM

Did you notice this:

Code:

LCD_CTRL	Equ	PORTA
LCD_TRISA	Equ	PORTA

Have you connected them well? Or did you adjust the contrast?

meera83 · 11th June 2007, 03:44 AM

i didn't connect anything to CONTRAST part, what use of this part??

bananasiong · 11th June 2007, 03:49 AM

Quote:

Originally Posted by meera83

i didn't connect anything to CONTRAST part, what use of this part??

Obviouly to adjust the contrast

Maybe you haven't seen this yet:
http://winpicprog.co.uk/pic_tutorial_lcd_board.htm

ericgibbs · 11th June 2007, 08:09 AM

Quote:

Originally Posted by meera83

i didn't connect anything to CONTRAST part, what use of this part??

Hi,
You require a 10K0 potentiometer, between +5V and 0V and the wiper of the pot connected to Vo of the LCD pcb. Adjusting the pot will set the 'contrast' of the LCD so that you can see the LCD characters.
At first, set the contrast so that you can just see the pixel blocks on the LCD.

Have a look where the +5V and 0V wires are connected to the LCD pcb, next them [on my lcd] is pin#3, which is Vo.

Does this help?

reaver26 · 25th October 2009, 11:24 AM

this will help on my upcoming project....

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11th June 2007, 02:36 AM	#17
meera83	Help!Help! i really don't know what can i do with the source code.. I had make some changing to Nigel's LCD tutorial according to my port pin, from PICDEM 2 PLUS circuit shcematic, the port pin RA1 - E RA2 - RW RA3 - RS DB4 - RD0 DB5 - RD1 DB6 - RD2 DB7 - RD3 but the LCD still don't have any respond..

11th June 2007, 02:43 AM	#19
meera83	what's mean by this code? LCD_RS Equ 0x04 ;LCD handshake lines LCD_RW Equ 0x06 LCD_E Equ 0x07 if my port pin connection is like RA1 - E RA2 - RW RA3 - RS DB4 - RD0 DB5 - RD1 DB6 - RD2 DB7 - RD3 then what location should i write?? thanks..

11th June 2007, 03:21 AM	#23
bananasiong	Did you notice this: Code: LCD_CTRL Equ PORTA LCD_TRISA Equ PORTA Have you connected them well? Or did you adjust the contrast? __________________ bananasiong

11th June 2007, 03:44 AM	#24
meera83	i didn't connect anything to CONTRAST part, what use of this part??

25th October 2009, 11:24 AM	#27
reaver26	this will help on my upcoming project....