Stupid question about LCDOUT

[Glenn]

Well, since I got some help from you guys with my servoproblems I now have a more or less working routine for that, well, now I wanted to have a LCD to put some debug data to, reading the PBP manual it looks so easy, so I started with building the example in PBP manual:

http://www.melabs.com/resources/pbpm...2-5_35.htm#535

The only change I did was using a 16F628A instead of the 16F84A, therefore I removed the xtal and the two caps.

Then I wrote a very small program like this:

@ device INTRC_OSC_NOCLKOUT,MCLR_OFF,LVP_OFF,WDT_OFF,PROTECT_OFF
DEFINE OSC 4	' Lets work at 4MHz
CMCON = 7        ' Disable comparators

pause 500          ' grace time for the LCD to initialize.

main:
	LCDOUT $FE, 1, "Hello world" ' Clear display and show text
	pause 1000		          ' Wait 1s
	goto main			   ' Go back

Well, nothing happens.. no sign of text on the LCD, no matter how I adjust the pot.. and I cant see why ?

The LCD is a Sharp LM16A211, which is Hitachi 44780 compatible, and I also have used several of these for other applications so they are ok.

[b1arrk5]

Hi Glenn,

I believe that you also need the Defines shown in the MELabs manual, before you use the LCDOUT command.

Good Luck,

Jerry

[Glenn]

Well, if I understand it correctky its not needed if you use the default stuff, but I tried to add the whole define-block mention in the manual, and there is no difference.

I also tried to put a LED on a pin and make it flash so I know that the pic is "running"..

[skimask]

The only change I did was using a 16F628A instead of the 16F84A, therefore I removed the xtal and the two caps.

Got a pullup on RA4?
Try putting the xtal and the caps back on there anyways? Just in case the config fuses didn't take.
Put an LED on an unused pin for grins and see if it blinks for ya... I ALWAYS use a heartbeat LED or two on all my projects. It takes sooo much guesswork out of the equation...

@ device INTRC_OSC_NOCLKOUT,MCLR_OFF,LVP_OFF,WDT_OFF,PROTECT_OFF
DEFINE OSC 4	' Lets work at 4MHz
CMCON = 7        ' Disable comparators
pause 500          ' grace time for the LCD to initialize.
led var portb.0
main: led = 1 
        LCDOUT $FE, 1, "Hello world" ' Clear display and show text
	pause 500		          ' Wait 1/2 sec
        led = 0
        LCDOUT $FE, 1, LED Off"
        pause 500
        goto main			   ' Go back

[Glenn]

Got a pullup on RA4?

Yes, I accidenticaly made it a pulldown first, but when it didnt work I checked all connections and fixed that.

Try putting the xtal and the caps back on there anyways? Just in case the config fuses didn't take.
Put an LED on an unused pin for grins and see if it blinks for ya... I ALWAYS use a heartbeat LED or two on all my projects. It takes sooo much guesswork out of the equation...

As I wrote I already did that ..I also like the idea with a heartbeat (Even if it doesnt look as nice at it does on my old HP PA-RISC machine if I have a spare pin.

It flashes so the oscillator doesnt seem to be the problem.

[Archangel]

Well, since I got some help from you guys with my servoproblems I now have a more or less working routine for that, well, now I wanted to have a LCD to put some debug data to, reading the PBP manual it looks so easy, so I started with building the example in PBP manual:

http://www.melabs.com/resources/pbpm...2-5_35.htm#535

The only change I did was using a 16F628A instead of the 16F84A, therefore I removed the xtal and the two caps.

Then I wrote a very small program like this:

@ device INTRC_OSC_NOCLKOUT,MCLR_OFF,LVP_OFF,WDT_OFF,PROTECT_OFF
DEFINE OSC 4	' Lets work at 4MHz
CMCON = 7        ' Disable comparators

pause 500          ' grace time for the LCD to initialize.

main:
	LCDOUT $FE, 1, "Hello world" ' Clear display and show text
	pause 1000		          ' Wait 1s
	goto main			   ' Go back

Well, nothing happens.. no sign of text on the LCD, no matter how I adjust the pot.. and I cant see why ?

The LCD is a Sharp LM16A211, which is Hitachi 44780 compatible, and I also have used several of these for other applications so they are ok.

try this

@ DEVICE INTRC_OSC_NOCLKOUT,MCLR_OFF,LVP_OFF,WDT_OFF,PROTECT_OFF
DEFINE  LCD_COMMANDUS 1000 'Defines how fast PIC sends Data and 
'                          'Commands to LCD change to suit LCD's 
'                          'needs. 
DEFINE LCD_DATAUS 50	     'Define delay time between sending LCD
                           'commands.
                           'Define delay time between data sent.
DEFINE OSC 4	' Lets work at 4MHz
CMCON = 7        ' Disable comparators

pause 500          ' grace time for the LCD to initialize.

main:
	LCDOUT $FE, 1 ' CLEAR LCD
        PAUSE 10
        LCDOUT $FE,2, "Hello world" ' LINE 1 and show text
	pause 1000		          ' Wait 1s
	goto main			   ' Go back
END

I'm not sure about the config statement as I do not use PM assembler anymore

[Glenn]

try this

No, didnt work either

..I think I going to try to dig some 16F84A's up and try with that instead, since the example is made for 16F84.

[Acetronics2]

Hi,

Did you notice the reversed pinout numbering ??? ... from right to left.

Alain

[Glenn]

Hi,
Did you notice the reversed pinout numbering ??? ... from right to left.

Yes, I have the datasheet for the displays since I used them in aother project (connetced to the parport of a computer)

[skimask]

Yes, I have the datasheet for the displays since I used them in aother project (connetced to the parport of a computer)

Using one of those 'solderless breadboards' for the project?
Double check those connections!!! They might be hooked up right, but are they making contact...

[Glenn]

Ok, no I changed the pic to a 16F84A, and connetced a Xtal and two caps, still doesnt work

Very strange.

Now I test with:

@ device HS_OSC,WDT_OFF,PROTECT_OFF
DEFINE OSC 4	' Lets work at 4MHz

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 500 ' grace time for the LCD to initialize.

main:
	LCDOUT $FE, 1, "Hello world" ' Clear display and show text
	high portb.0	' Turn the LED on.
	pause 1000	' Wait 1s
	low portb.0	' Turn the LED off.
	pause 1000	' Wait 1s
	goto main	' Go back