PICBASIC PRO 16F84 with 16X02 LCD

[Marin]

Hello to all, first time to write here!!!


So I've got a bit of problem getting work mine LCD and uP.....

I've already have connected pins from PORTA.0 to PORTA.3 to pushbuttons with pull-up resistors, and PORTA.4 to transistor which drives relay on mine bord....so I've got whole PORTB emty..and there is where mine LCD is connected, and because of that I must tell pibasic different definition about connection of LCD.....so i did that and still I haven't anything on mine LCD.

This is how i connected PIC16F84 and LCD

PIC LCD

PORTB0 ---> Enable (PIN 6)
PORTB1 ---> RS (PIN 4)
PORTB4 ---> DB4 (PIN11)
PORTB5 ---> DB5 (PIN12)
PORTB6 ---> DB6 (PIN13)
PORTB7 ---> DB7 (PIN14)

PIN 1(GND) i PIN 5 (RW) are grounded (GND)
PIN2 is on +5V, PIN 3 is connected to +5V also via trimmer pot of 10K for contrast.

This is mine code:


DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTB
DEFINE LCD_RSBIT 1
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 0
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 2000
DEFINE LCD_DATAUS 50

LCDOUT $FE, 1, "HELLO"
LCDOUT $FE, $C0, "WORLD"



That's it...ann I still didn't getting any on LCD.....

LCD is PC1602 HD44780 compatibile.....

Any ideas??

[Dave]

Marin, Where is the other side of the pot connected to? It should be between + 5 and ground. Most LCD displays require anywhere between 0 volts and 1 volt for the contrast voltage.

Dave Purola,
N8NTA

[Marin]

Dave, thanks for replay!

I know for that contract....I didn't have pot so i put two 10K resistor in seria and getting contrast V from middle...something about 2,5V!

Is it this OK?

[Archangel]

Hi Marin,
Is there more to this code which is unseen?
You should make it a practice to set your config fuses in code
and set the TRIS Registers too, also define your OSC speed.
Are you using a crystal, or resonator or are you trying to use
the internal osc?

DEFINE OSC 4          ' for 4 mhz osc
TRISA = %00001111 ' the ones stand for inputs
TRISB = %00000000  ' the zeros stand for outputs

Study this thread:
http://www.picbasic.co.uk/forum/show...iguration+fuse

Add this just before your first LCDOUT statement to allow the LCD time to initialize:
Pause 500 ' or a thousand or sometimes a little more

HTH
JS

[Marin]

HI Joe! Thanks for replay.....but still I have dead LCD :-(

That I wrote is whole mine code....this is code now:

DEFINE OSC 4 ' for 4 mhz osc
TRISA = %00001111 ' the ones stand for inputs
TRISB = %00000000 ' the zeros stand for outputs


DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTB
DEFINE LCD_RSBIT 1
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 0
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 2000
DEFINE LCD_DATAUS 50


pause 2500


LCDOUT $FE, 1, "HELLO"

[Dave]

Marin, You should use a pot of about 5 or 10 k between +5 and ground as the 2 10k's you have will not get the desired results. When you have the pot installed place it at the 0 volt position and start ramping it up. You will see the background boxes (pixels) start to diminish. This is the optimum contrast level. Read the level with a voltmeter and you will see that it is between 0 and 1 volt.

Dave Purola,
N8NTA