I suspect that the issue is in the lcd_puts procedure combined with my
ISR routine:

void lcd_puts(const unsigned char * s) {
        while(*s)
                lcd_putch(*s++);
}

In the ISR I only increase some counters and have some serial procedures
run. Could it be that the compiler (PICC) isn't saving some info vital
for the LCD procedure ?

Lucian

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Lucian
Sent: 12 mai 2004 23:15
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC:] LCD Sometimes Displaying Unwanted Characters

The problem might be elsewhere, but the fact is that this error appears
mostly when I'm displaying long strings (max 12 characters) read from
the EEPROM. I have a menu that I receive serially and I store it in
EEPROM and then I read the 2 lines I need to display. The code to
display the lines is:

        //menustart is the coordinate of the first line to display from
the menu
        //lung is the length of the first line to display
        for (aux=0;aux<lung;aux++)
                lcd_putch(eeprom_read(LIST_DATA+(16*menu_start)+aux));
        lcd_goto(0x40);
        //lung = the length of the second line to display
        for (aux=0;aux<lung;aux++)

lcd_putch(eeprom_read(LIST_DATA+(16*(menu_start+1))+aux));

I don't see anything wrong in this code. Do you ?

Lucian
-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Sergio Masci
Sent: 12 mai 2004 23:08
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC:] LCD Sometimes Displaying Unwanted Characters

----- Original Message -----
From: Bob Ammerman <rammerman@VERIZON.NET>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Wednesday, May 12, 2004 7:47 PM
Subject: Re: [PIC:] LCD Sometimes Displaying Unwanted Characters


> > At this moment I am not sure whether it is a hardware or a software
> > problem. It is strange that it displays the character before the
correct
> > one.
> >
> > Lucian
>
> Is there anything else tied to the LSBit of the data bus that could be
> pulling it low somehow?
>
> Bob Ammerman
> RAm Systems

The OP described the word "MENU" being corrupted to "MEMU"

M = hex 4D
N = hex 4E

This is not a single bit error.

The OP also said this LCD is running in 4 bit mode. My money is on a
software
error, timing maybe, or using other bits in the same port incorrectly.

Regards
Sergio Masci

http://www.xcprod.com/titan/XCSB - optimising PIC compiler

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