LED moving message display - interfacing problems! RS232

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I recently purchased some led message boards from auction and need some
information on them ..... hopefully someone here can help?

The signs are made by "LEISURE UNLIMITED AUSTRALIA" - LUA Electronics, and
are about 1.3 metres long - dot matrix single line RED display...30+ chars
(cant tell exactly as the characters use less than one LED block each)

When the signs are powered up, they simply display a 6 digit serial number
(same number as shown on the back of each unit - matches the units serial)
and then they just sit there displaying that number - I assume, waiting for
some valid commands.
Leisure Unlimited Australia, LUA Electronics used to be here:
LUA Electronics Pty Ltd. 11 Redwood Drv Notting Hill VIC 3168, but are shown
as a de-registered company on the AISC site, and obviously, nobody answers
the old phone number....yep - tried anyway!


I found some software I thought might control them here......

http://www.dorianstudios.net/Computer%20Electronics.htm

but so far, have had no luck!

I made up a serial port null modem cable after checking that the sign DB9
connector has only pins 2, 3 and 5 connected......but no joy.....tried a few
different types of null modem cable too.

By taking a peek inside the software, the only settings I could see were
9600 baud, 8 bits, no parity and 1 stop bit......so these are the settings I
have been using - although I have also tried others too with no luck.

The controller for the sign uses a TC232CPE level converter, an 8031
processor, one RAM chip (HY6264ALP-10) and a 27C64 EPROM.
I don't have anything else much that i can tell you about it, so I am hoping
that someone here has used them before, or might be able to help me
interface to it.

Would dumping the contents of the EPROM help to nut this out?? Anyone likely
to be able to make sense of it?


If any one has any software to use these or knows where i could get it from
it would be much apreciated.

If anyone could even jusdt point me in the way of someone who used to work
at this company that would be great too

Thanks in advance !


Re: LED moving message display - interfacing problems! RS232


Nobody here has played with RS232 or 8031's?????

Anyone using a LED message sign at work?  What brand is it? How is it
connected?


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Re: LED moving message display - interfacing problems! RS232



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  I'm sure at least some of us have played with RS232 and/or 8031's, just not
within the message board you outlined.  And even if one hasn't, it really
doesn't matter anyway.

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  The ones that I played with (a million years ago) were RS232-interfaced,
(back when RS232 was trendy), but you used a dumb terminal to talk to it.
Certain characters were used for control purposes, everything else
(alphanumerics) were used for display.

  This doesn't help you of course, not only because can I not remember the
brand of the displays, no other brand might help either - simply because there
are no communications standards for these things.

  I've heard of AT style keyboard connected interfaces, USB, parallel printer
port interfaced, you name it, I've "heard" of them all.  All of them different
with the way one programmed the text.

  Regardless, unless someone doesn't have that model you have and knows how to
drive it, nothing else will help.


  I would be cynical of the usefulness of "looking under the bonnet" because
if you want to disassemble the code, by the time you go through it, it may
very well be cheaper to buy something off the shelf that has software and
instructions all nicely laid out for you.

  When purchasing things like these, you really have to do your homework
first, otherwise you might be buying a vintage black box.  Very nice, but
black boxes don't really do anything exiting by themselves.

  Keep looking, you might get lucky and hear from someone that has used them.

  Otherwise, it might be useful to stick a protocol analyser in there and see
if the boxes bounce any bytes back in response to your probing.  It'll give
you an idea of the speed at least.
  Failing all the above, some trial and error may be called for.

  Good luck.
--
Linux Registered User # 302622
<http://counter.li.org

Re: LED moving message display - interfacing problems! RS232


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As John mentioned, it's a lot of effort to try and reverse engineer
something like that, and I wouldn't bother. Sounds like you've tried
the basics, so I'd give at that point.
What I *would* do however is to simply write new software for it from
scratch, that should be quicker than trying to decode what the old one
does. Either use the existing 8031 with a new ROM, or replace it with
the micro of your choosing. Should use all discrete hardware, so that
should be fairly easy to figure trace out and figure out how to drive
the LED's.

With your own software you get the benefit of making it do exactly
what you want, likely with more features than the original software
contained.

Dave.


Re: LED moving message display - interfacing problems! RS232


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not so sure about that Dave.

I did a moving message board (see Silicon Chip 1989, over 4 issues)

To assemble the text, make it move, calculate the next frame ahead, and
have it move up, down, left or right, then add all the scroll left,
right, up down, etc, etc.,

Then if you want animated 3 colour crocodiles, space vehicles,
telephones, flowers, etc, etc, as I did, it may take about 18 months of
your spare time. A part time labor of love.

If you just want to write "Happy Birthday" sure. That's how I started.

BTW Princo Coasters,
I used an XT keyboard for data input. That's what was popular and
convenient then. :-)

Sure, yours is RS-232, if you can't reverse engineer the comms code,
scrap it, and buy a very cheap TW import.


Don...



--
Don McKenzie

Site Map:            http://www.dontronics.com/sitemap
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Re: LED moving message display - interfacing problems! RS232


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18 months is a long time. Assembler? Was most of your high level
functionality internal to the message board, or external to it like on
a PC?

With a high level language compiler and possibly some pre-written code
for the high level stuff (text-to-bitmap etc), it need only take a
fraction of that time. If you offload the high level stuff to the PC
then the actual LED message driving part of it becomes relatively
easy.

The problem PrincoCoasters might have though is that he might have to
do all that anyway. Even if he decodes the software and gets it to
talk he might find that the message board is nothing more than a low
level device which holds a bitmap image and scrolls it. i.e. it might
not have any ASCII to bitmap decoding built in, so he won't be able to
simply send it ASCII text and have it displayed. In that case a PC
application would have to be written anyway.

Dave.


Re: LED moving message display - interfacing problems! RS232



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all z80 assembly Dave, and part time as I say.
Mind you, I just kept writing it until I was happy and exhausted all
possibilities. :-)

started off as a single colour display, (Silicon Chip articles) but I
added alternate rows of red and green LEDs to produce orange as well, so
it became a 3 colour device.

http://www.dontronics.com/z80.html
has the code.

Don...



--
Don McKenzie

Site Map:            http://www.dontronics.com/sitemap
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Re: LED moving message display - interfacing problems! RS232


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You might be interested (or relieved) to know you don't hold the
record for development time for a published project. I think that
honor goes to Peter Baxter's 100MHz Logic Analyser in EA which took in
the order of 5 years to develop, only to be narrowly beaten to
publication by my 40MHz Logic Analyser project by a couple of months!
(my one only took a few months to develop)

Dave.


Re: LED moving message display - interfacing problems! RS232



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Be aware that Z80 code differs widely from 8051 (8751, 8031) code. I used
both, ever wrote even disassemblers.

petrus bitbyter



Re: LED moving message display - interfacing problems! RS232



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I have a suspicion that LUA morphed into Axent Global

<http://www.axent.com.au/



Re: UPDATE: Eprom dump from sign #000618




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I've never programmed a 8031 or any of its relatives, but after a
quick consultation with Mr G, I would guess it is at location 003B
(reference to SBUF, aka SFR 99 = Serial Data Buffer).

Could that be some 'command' decoding just beyond that?


Andy Wood
snipped-for-privacy@trap.ozemail.com.au

Re: UPDATE: Eprom dump from sign #000618



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As I said, you really need the datasheet of the 8051 (8031, 8751).

The first instruction jumps to address 0x800 where a lot of registers are
initialised. Amongst them SCON (Serial Control) which is set to 0x70 so an
8-bit UART is defined. The Baudrate is variable which means it is defined by
a timer and the X-tal frequency.

I checked neither the Baudrate nor interrupt setting but I found the serial
interrupt service routine at address 0x23. It looks like the routine handles
some other interrupt(s) as well but at address 0x2D it checks the receive
interrupt flag (RI) explicitely. If set it jumps to 0x3B and picks the
received byte from SBUF. From that line on you can find out what actions are
taken depending on the contents of SBUF. A 0x1B (ESCAPE) for instance
results in placing a 0 in r2. The routine goes up to 0xD2 but always exits
via 0x3A (the reti instruction). No doubt the actions depend also on the
contents of the registers which in turn may contain values set by earlier
received bytes. I saw at least r0 through r5 used. But you can find out what
characters have some meaning and which ones, if any, are discarded.

petrus bitbyter



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