Problem with LCM-SO1602DTR/M LCD on Picdem 2 Plus Demo Board

[Dominik]

Hello

I have a problem with the LCD display on the Picdem 2 Plus Demo Board 2006.
I can't display anything using the lcd.c driver that I tried to update or other programs I found at here as lcdd.c.

The pin connection is as follows:
D0 D4
D1 D5
D2 D6
D3 D7
D4 rs
D5 rw
D6 enable
D7 power

If someone has a working driver or has any idea to help me it will be very welcome.
Thank you

Best reards,

Dominik

[PCM programmer]

There are two threads on this.

In this thread, we discover that the LCD's "busy" bit doesn't work,
on at least on some of the "Rohs update" PicDem2-Plus boards.
http://www.ccsinfo.com/forum/viewtopic.php?t=29768

In this thread, the person says it was only necessary to turn on
power to the LCD, and then it worked.
http://www.ccsinfo.com/forum/viewtopic.php?t=29521

I still don't have one of the new "Rohs update" boards.
Here is what I believe you should do:

1. Use the "Flex" lcd driver at this link:
http://www.ccsinfo.com/forum/viewtopic.php?t=24661

2. Change the pin list at the start of the driver, so it uses these pins:

[Dominik]

Thank you Mr PCM Programmer

I've tried your test program including the flex_LCD with the update you said and it's working !

The only problem remaining is that there's a strange character displaying on the LCD just after the characters that I want to display.

Kind regards,

Dominik

[PCM programmer]

Post a test program that shows the problem. Make it be similar
to the one that I posted, but have it show your problem. (Keep it small).

[Dominik]

The program I used is the one you sent to me :

#include <16F877.h>
#fuses XT,NOWDT,NOPROTECT,BROWNOUT,PUT,NOLVP
#use delay(clock=4000000)

#define LCD_POWER PIN_D7

#include "Flex_LCD.c"

int x = 1;


//============================
void main()
{
output_high(LCD_POWER); // Turn on power to LCD
output_low(LCD_RW); // Set R/W pin on LCD to a low level
lcd_init(); // Initialize the LCD

lcd_putc("Hello");


while(1);
}

And what is dsiplayed on the LCD is ---> Hello†

[PCM programmer]

Does your PIC have a 4 MHz crystal ?

[Dominik]

The Quartz is the one on the Picdem Board ---> JWT 4.00/5V MHZ and the PIC I'm using is a 16F877A

[PCM programmer]

[Dominik]

I've changed the line :

[PCM programmer]

Try adding an additional delay after applying power. There's already
a delay statement in the Flex driver's init_lcd() routine, but maybe it's
not enough. Add the line shown in bold below, in exactly that position:

[Dominik]

I tried by adding :

[PCM programmer]

Also, post your compiler version. It's a 4-digit number in this format x.xxx
and you can find it at the top of the .LST file, which is in your project
directory. Don't post any numbers that come after the version number.

[Dominik]

The version I found in the LST file is :

CCS PCM C Compiler, Version 4.013

[PCM programmer]

That's an early version. It's possible that it's causing a problem, but it
may not be. I briefly compared the .LST files between vs. 3.249 and
4.014 (don't have 4.013) and I didn't see any differences in the areas
where I looked. I don't have time to look at all of it.

I'm trying to think of what could cause an extra character at the end
of a line.

1. It's possible that the LCD control lines are being left in some
indeterminate state, and somehow this causes a bad extra character.

2. Perhaps the LCD power pin is being glitched at the end of the
string, for some unknown reason, and this causes a bad character.

3. Perhaps the compiler isn't properly detecting the "end of string"
in the "Hello" string, and is sending a garbage character at the end.

4. The "busy" delay in the lcd_send_byte() routine may be too low.

5. The initialization bytes in the Flex driver not be exactly correct
for this LCD.

6. It's possible that you didn't do all the changes that I said in an earlier
post, such as commenting out the "#define USE_LCD_RW 1" line
in the Flex driver.

7. It may be that you're running a different test program than the one
that you posted. I may not be looking at your real program, and
therefore, I can't see the actual problem.


Let's try an experiment, assuming that it's item #4. Edit the Flex_lcd.c
driver, in lcd_send_byte() routine. See the line shown in bold below ?
Increase it to a much larger value, such as 500 us. Re-compile, and
re-program, and see if it helps.

[Dominik]

I've updated the compiler's version to the :

CCS PCM C Compiler, Version 4.038 and now I don't have no more that character problem with that program.
But I have one when I want to display a value as below: