AVR-Chat

I'm tinkering with a 16x2 HD44780 LCD display attached to my dragon 
rider. The uC is a ATmega32 feeding the LCD through PortA and using 
JTag as the debugger/programmer. I am using Peter Fleury's lcd 
libraries (http://jump.to/fleury). The only thing I've changed in the 
header is that Im connecting to a 2 line LCD on PortA and running at 
8Mhz.

The problem I am getting is pertaining to the code I have posted 
below. It seems I am getting artifacts on my screen and I'm not quite 
sure why? I am running a couple loops in order to marquis topstr and 
lowstr across the lcd display on both lines. The top one comes from 
the right and the lower from the right. They work fine except for 
erroneous text I keep seeing on the display. (I drew an image as an 
example. The ¶- artifact starts in the middle and scrolls opposite of 
what that line is suppose to do. I thought maybe it's displaying extra 
information in memory as when I have put userChars into memory to 
display it, the ¶ changes to the character from userChars but reverts 
if I remove the code which introduces userChars (as you can see I have 
it commented out now). Erasing the Flash and EEPROM memory doesnt seem 
to change anything. After a reprogramming, it just reverts back to the 
same problem. 

If any of you have used Peter Fleury's lcd code or might know what is 
going on through this rough but I hope extensive description, I would 
appreciate the help. Thanks

What it should look like (the two stars move towards eachother to the 
opposite side)->
            *---... |
..---*              |

What it looks like (the artifact moves with the upper star from the 
middle till it meets the bottom star and disappears)->
            *---... |
..---*  ¶-          |


-Code-
#include <avr/io.h>
#include "lcd.h"
#include <util/delay.h>				// _delay_ms(#) Header
#include <avr/pgmspace.h>			// To access eeprom

//static const PROGMEM unsigned char userChars[] =
//{
//	0x0,0xA,0x1F,0x1F,0xE,0x4,0x0,0x0            // Test character
//};

void delay_ms(int cnt)
{
  	while(cnt-->0) _delay_ms(1);
}

int main(void)
{
  	const char topstr[16]="*---...         ";
  	const char lowstr[16]="*---...         ";
	
	int i = 15;
	int j = 0;
	int k = 0;

  	lcd_init(LCD_DISP_ON);  //Initialize LCD with the cursor off
  	lcd_clrscr();           //Clear the LCD screen
  	lcd_home();
  	
 	for (i = 15; i >= 0; i--)
  	{
  		lcd_gotoxy(i,0);
		lcd_puts(topstr);
		
		
		for ( j = 0; j < k+1; j++)
		{
			lcd_gotoxy(k-j,1);
			lcd_putc(lowstr[j]);
		}

		k++;

		delay_ms(500);
		lcd_clrscr();
  	}

//	lcd_command(_BV(LCD_CGRAM));
//  for(int i=0; i<8; i++)
//  {
//  	lcd_data(pgm_read_byte_near(&userChars[i]));
//  }
//
  	for (;;)
  	{
//  	lcd_gotoxy(0,1);
//		lcd_putc(0);
  			// Do nothing forever (Message already 
displayed on LCD)
  	}
}

I am sorry if the formatting of my post is off. Not quite sure whether 
yahoo groups wants it to look good or not. If I read the post from the 
group there is no formatting but if I post a reply, the text is 
formatted. 

I also wanted to add that I'm using AVR Studio with AVR-GCC.

--- In AVR-Chat@yahoogroups.com, "Jeremy" <luminare@...> wrote:
>
> I'm tinkering with a 16x2 HD44780 LCD display attached to my dragon 
> rider. The uC is a ATmega32 feeding the LCD through PortA and using 
> JTag as the debugger/programmer. I am using Peter Fleury's lcd 
> libraries (http://jump.to/fleury). The only thing I've changed in 
the 
> header is that Im connecting to a 2 line LCD on PortA and running at 
> 8Mhz.
> 
> The problem I am getting is pertaining to the code I have posted 
> below. It seems I am getting artifacts on my screen and I'm not 
quite 
> sure why? I am running a couple loops in order to marquis topstr and 
> lowstr across the lcd display on both lines. The top one comes from 
> the right and the lower from the right. They work fine except for 
> erroneous text I keep seeing on the display. (I drew an image as an 
> example. The ¶- artifact starts in the middle and scrolls opposite 
of 
> what that line is suppose to do. I thought maybe it's displaying 
extra 
> information in memory as when I have put userChars into memory to 
> display it, the ¶ changes to the character from userChars but 
reverts 
> if I remove the code which introduces userChars (as you can see I 
have 
> it commented out now). Erasing the Flash and EEPROM memory doesnt 
seem 
> to change anything. After a reprogramming, it just reverts back to 
the 
> same problem. 
> 
> If any of you have used Peter Fleury's lcd code or might know what 
is 
> going on through this rough but I hope extensive description, I 
would 
> appreciate the help. Thanks
> 
> What it should look like (the two stars move towards eachother to 
the 
> opposite side)->
>             *---... |
> ..---*              |
> 
> What it looks like (the artifact moves with the upper star from the 
> middle till it meets the bottom star and disappears)->
>             *---... |
> ..---*  ¶-          |
> 
> 
> -Code-
> #include <avr/io.h>
> #include "lcd.h"
> #include <util/delay.h>				// 
_delay_ms(#) Header

> #include <avr/pgmspace.h>			// To access eeprom
> 
> //static const PROGMEM unsigned char userChars[] =
> //{
> //	0x0,0xA,0x1F,0x1F,0xE,0x4,0x0,0x0            // Test character
> //};
> 
> void delay_ms(int cnt)
> {
>   	while(cnt-->0) _delay_ms(1);
> }
> 
> int main(void)
> {
>   	const char topstr[16]="*---...         ";
>   	const char lowstr[16]="*---...         ";
> 	
> 	int i = 15;
> 	int j = 0;
> 	int k = 0;
> 
>   	lcd_init(LCD_DISP_ON);  //Initialize LCD with the cursor off
>   	lcd_clrscr();           //Clear the LCD screen
>   	lcd_home();
>   	
>  	for (i = 15; i >= 0; i--)
>   	{
>   		lcd_gotoxy(i,0);
> 		lcd_puts(topstr);
> 		
> 		
> 		for ( j = 0; j < k+1; j++)
> 		{
> 			lcd_gotoxy(k-j,1);
> 			lcd_putc(lowstr[j]);
> 		}
> 
> 		k++;
> 
> 		delay_ms(500);
> 		lcd_clrscr();
>   	}
> 
> //	lcd_command(_BV(LCD_CGRAM));
> //  for(int i=0; i<8; i++)
> //  {
> //  	lcd_data(pgm_read_byte_near(&userChars[i]));
> //  }
> //
>   	for (;;)
>   	{
> //  	lcd_gotoxy(0,1);
> //		lcd_putc(0);
>   			// Do nothing forever (Message already 
> displayed on LCD)
>   	}
> }
>