How to use a 4x20 lcd.

Hi,

I need to use an lcd display for my project and what we have here is a
4x20 lcd. However, I can't find any starters's guide for using such device.
Btw, I'm using a zilog mcu and I have enough I/O pins for all the pins of
the lcd. It's better if your reference or sample code is in zilog syntax.
Thanks!

"sani_figs" <adrian_figui@yahoo.com> wrote in message
news:3LmdnbCRkPYslBLVnZ2dnUVZ_gSdnZ2d@giganews.com...
> Hi,
>
> I need to use an lcd display for my project and what we have here is a
> 4x20 lcd. However, I can't find any starters's guide for using such
device.

Try looking for a datasheet of the HD44780 LCD controller chip. This one or
one of the gazillion clones is used in almost every character LCD and they
all follow the same command syntax.

> Btw, I'm using a zilog mcu and I have enough I/O pins for all the pins of
> the lcd.

Make sure you create a cycle time of 1 us or slower on the pins. The HD44780
is a slow chip....

Meindert

On Tue, 29 Jul 2008 07:14:41 -0500, "sani_figs" <adrian_figui@yahoo.com>
wrote:

>Hi,
>
>I need to use an lcd display for my project and what we have here is a
>4x20 lcd. However, I can't find any starters's guide for using such device.
>Btw, I'm using a zilog mcu and I have enough I/O pins for all the pins of
>the lcd. It's better if your reference or sample code is in zilog syntax.

The Optrex manual is a pretty good guide to the character LCD displays.
http://www.optrex.com/pdfs/Dmcman_full.pdf

The initialization routines are where many first-time users have
problems. The manual above has step-by-step directions for
initialization in 4-bit and 8-bit modes. Be sure to follow them,
including the required delays between steps.

Once it's initialized, you'll have the choice of using either the busy
flag or waiting a pre-set maximum period between characters. Note that
some clones may require different max delays and some instructions,
e.g., clear and home, may require more than a single character delay.

-- 
Rich Webb     Norfolk, VA

Hi,

Thanks! I think these info will suffice for now. :)

In message <3LmdnbCRkPYslBLVnZ2dnUVZ_gSdnZ2d@giganews.com>, sani_figs 
<adrian_figui@yahoo.com> writes
>Hi,
>
>I need to use an lcd display for my project and what we have here is a
>4x20 lcd. However, I can't find any starters's guide for using such 
>device.
>Btw, I'm using a zilog mcu and I have enough I/O pins for all the pins 
>of
>the lcd. It's better if your reference or sample code is in zilog 
>syntax.
>Thanks!
The daddy...

http://www.epemag.wimborne.co.uk/resources.htm

How to use Intelligent LCDs

Excellent starter guide.
-- 
Clint Sharp

Hi, the display is not consistent with every restart of my lcd display.
when trying to display a simple "Hello World!", the output on the lcd is
sometimes: "Hel o W rld!", "Hello W rlt!", or "H  lo Wo ld!".
Any insights on this matter? 

Thanks! 

On Mon, 04 Aug 2008 05:29:35 -0500, "sani_figs" <adrian_figui@yahoo.com>
wrote:

>Hi, the display is not consistent with every restart of my lcd display.
>when trying to display a simple "Hello World!", the output on the lcd is
>sometimes: "Hel o W rld!", "Hello W rlt!", or "H  lo Wo ld!".
>Any insights on this matter? 

There are a few different ways to implement the interface to a character
LCD display correctly. However, the number of ways to do it incorrectly
is very large.

With no other information as to how you've implemented the interface
(BUSY flag or wait-per-character? busy-wait loops or timer interrupt?)
not to mention the rest of it (FIFO queue or a "direct from printf()"?)
I'll go with: timing.

-- 
Rich Webb     Norfolk, VA

sani_figs wrote:
> 
> Hi, the display is not consistent with every restart of my lcd
> display. when trying to display a simple "Hello World!", the
> output on the lcd is sometimes: "Hel o W rld!", "Hello W rlt!",
> or "H  lo Wo ld!".  Any insights on this matter?

My guess is that you are not checking some device (the display?) is
free before sending to it.

-- 
 [mail]: Chuck F (cbfalconer at maineline dot net) 
 [page]: <http://cbfalconer.home.att.net>
            Try the download section.