Hi John

I was using an LCD from Hantronix last year that would get into a latch up
state when I reset my pic.


I put pull ups (and maybe pull downs, I'm not at work and my one remaining
brain cell is holding my name) on the RS, enable and W/R lines and I was
able to keep it straight most of the time.
I canned the thing half way through development and went to a Crystalfontz
because it was not RoHS compliant.

The Crystalfontz will crap out if I write to it when/if it is busy.
When I turn the port around on my PIC 18F6520 from R to W or vise versa if I
don't put a 50usec delay before I read or write the data does not either go
to the thing (out the port) or come from the thing (in the port) and I blow
on by to the next read or write life turns to carp.
I don't think it is capacitance on the lines (like the long cable guy
earlier) they are very short.
Mostly I do RF stuff here so I have a good idea about capacitance of my
boards.
I swear there is some kind of turn around where you can read/write the port
fast after it is turned around but you have to wait till it is ready to go. 
I'm going to do some more testing AM.
I'll figure it out eventually.
 Phillip
Things should be as simple as possible but no simpler
 
 
 
Phillip Coiner
CTO, GPS Source, Inc.
 
 
Your source for quality GNSS Networking Solutions and Design Services, Now!

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
kravnus wolf
Sent: Sunday, April 02, 2006 11:18 PM
To: Microcontroller discussion list - Public.
Subject: [PIC] LCD sanity

I have written code for the LCD from bgmicro

http://www.bgmicro.com/prodinfo.asp?sid=0968912037037037604814310&prodid=LCD
1022&page=1&cri=lcd&stype=3

I managed to get it started and printing characters on
it. What grips me is that if I reset the PIC through
MCLR quickly and numerous times the LCD just prints
blank! It seems that the LCD cannot handle quick
restart over and over again. I am left
clueless........

Thanks,
John

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