Hi-

I can't answer for the PICKIT code (I'm sure its fine).  However, I am just starting
with the ET ARM stamp set and their example code for the 4 digit LCD display is in
error.  I had to slow down the timing loops to get my display working.  I have used
that display in PIC designs without a problem, however this code uses time delays
rather than looking at the busy bit as my pic code does.  I'm pretty sure that the
specs on my display are faster than the Hitachi specs.  I don't have the data sheets
with me now to verify.  Just got through this exercise last week. Sigh.

Might I also suggest that if one wants to design his/her own code that one might try 
starting with the 8 bit interface to get some familiarity with the device, then
going to a 4 bit interface.  This is the process I went through although I tried
starting with a 4 bit interface.  This made the reading of the character ram on the
display a little easier.

  Cheers,

   Rich S.

---- Original Message ----
From:		Brooke Clarke
Date:		Mon 6/11/07 12:26
To:		piclist@mit.edu, Matthew Mucker
Subject:	[PIC] Interfacing to a Hitachi 44780 LCD in 4-bit mode

Hi Matthew:

There are a number of things that can go wrong besides what's already been 
mentioned.

1) some of the PIC code for the 44780 has bugs.
2) when trying to drive a nibble you often mess up the other bits since the 
tendency is to use Byte wide commands.
3) there are some time delays that need to be observed during the 
initialization of the LCD
4) it's best to read back the status bit.  If you don't then there's a gray 
area where you need to have delays so you're sure the LCD has finished 
processing the last command.  Some commands can take a L o n g   t i m e.

I highly recommend that you download the free code used in the PIC Kit 2 for 
the LCD interface.  It treats each pin separately which avoids problem (2) and 
gives you the freedom of assigning the LCD AFTER you have chosen the pins for 
the other stuff, no need to reserve a nibble.

-- 
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.precisionclock.com

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