Real Color Displays RC880

edited 2014-03-23 - 05:48:35 in Microcontrollers
I have an old Real Color Displays RC880 LED sign.· The CPU board no longer functions because the ROM chipped was damaged through improper insertion (meaning it got put in backwards blush.gif).· Getting it repaired by the manufacturer seems unlikely, as they haven't made these signs in nearly a decade.· I'm left with two options; one is to rewrite the firmware for the CPU board (it uses a Z80), which would require figuring out how the CPU board is built.

Option two is the more likely of the options (and happens to be the relevant option for this forum) is to create a new CPU board with an SX.· The actually LED display itself it fairly easy to control.· There are 7 rows by 80 columns of LEDs.· The rows are strobed and the columns are controlled by shift-registered daisy chained together.

So the question I'm asking would it be possible and reasonable to do that with the SX or would I be better off preserving the original CPU board?

Any input would be appreciated.



  • JonbJonb Posts: 146
    edited 2005-03-02 - 21:45:49
    That sounds like many sleepless nights and constant·head scratching to me. I would choose option 3, purchase a new LCD.
  • PJMontyPJMonty Posts: 983
    edited 2005-03-02 - 21:57:46
    I say go for it. Multiiplexing outputs (perhaps with some outboard hardware to increase the number of I/O lines if needed) is straightforward enough to do. The SX will have plenty of horsepower for the job plus the ability to handle the serial communication (I assume it gets info over a serial port) aspect of the project.

    I think you may need some outboard power transistors or the like to handle the currents involved. The SX can sink or source something like 30 ma, and when you multiplex you end up increasing the short term power so the LED is bright enough when being turned on and off rapidly. You'll find that you need more than 30 ma to get acceptable brightness depending on what the refresh rate is and how many LEDs can ever be on at one time.
      Thanks, PeterM
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-03-02 - 22:01:13
    It should be doable with an SX, your looking at 80 bytes of data nesessary, you could store a character map in memory, and text to be displayed (made of pointers into the character map) either in program memory or an serial EEPROM connected to the SX. The control seems pretty straight forward, it looks like you would have a single activation bit in the shift registers, push the row data out, clear row, shift, push next row, clear row, shift, etc. You probably would want to store your character map in columnwise fashion instead of the typical rowwise. That way you can get the data for the enitre column in one program memory fetch. Depending on how large your character set is, you could do a simple retw table, or an iread if your map is large, or you may want to put the map in serial eeprom as well since it will still be fast enough for the application.
  • CPUMANCPUMAN Posts: 55
    edited 2005-03-02 - 23:09:34

    Sounds like this will be an interesting challenge. I noticed that each column of LEDs has a current limiting resistor on it, but they allow around 65mA to flow at 5V, though I'm not sure the exact values of the LEDs... I would assume it might be a good idea to limit the current further untill I sure my software won't freeze on a particular LED and let the magic smoke out.

    As for controlling the rows the original CPU board has a TIP126 for each of the seven rows,·which is a NPN power transistor in a Darlington configuration, which is·capable of 5A. Which I suppose would make sense, because of the way the board is designed up to 80 LEDs can be on at any one time, all be it very brief.

    Hmm... you've all given me something to think about... I'm kinda excited at getting this thing working again since this is the only single line indoor LED sign I've seen that supports 64 colors (it has red, green and blue LEDs).

    Can someone suggest some good serial EEPROMs and serial RAM chips? Also what would be a good refresh rate? I know the MAX7219 for example runs at about 1KHz refresh rate.· Would 1KHz be a good speed, faster, slower?


    Post Edited (CPUMAN) : 3/2/2005 11:12:37 PM GMT
  • RickBRickB Posts: 393
    edited 2005-03-03 - 04:46:45
    A quick search for rc880 and real color found several results. Here is one.
    Several people are looking for manuals and programming software. I suspect that if you have either, you could arrange a trade for a copy of the eprom or a hex dump of the contents. Rom and ram requirements probably preclude use of an sx since it is rather limited in that regard.

  • BobbySixKillerBobbySixKiller Posts: 1
    edited 2005-03-13 - 17:04:25
    I own a fully functioning RC880 sign, and need software and manual.
    If you have any of them and you're still looking for the rom, we could help each other.
    On the other hand, if you have already given up with your old sign, maybe you would be interested in selling me a copy of software and manual.
    Please, contact me in this thread or·at my email address:

    [][/url] *remove NOSPAM*
  • CPUMANCPUMAN Posts: 55
    edited 2005-03-14 - 04:44:30
    I do have the manual and I am still looking for the ROM.· It would take me a little bit to digitize the manual but I would be happy to send it to you.

    As for software I'm still looking for that.· If I can find it I'd be happy to pass it on as well.

  • realtechrealtech Posts: 1
    edited 2005-07-19 - 01:45:03
    Could you send me a copy of the manual also? I'm really interested in the specs on the power supply.
    I have the display, and the remote but no power supply or manual. I'd also like any information on software and PC Pinout for a programming cable.

    Thanx In advance

    Gerard Cross
  • SpankophileSpankophile Posts: 1
    edited 2006-01-16 - 18:19:56
    Hi There!

    I'm pretty late to this party it appears!

    I have an RC880 sign + power supply, but no remote :-( Was anyone able to get pinouts/manuals/software for controlling this thing? And if so, would you mind passing it along?


  • CPUMANCPUMAN Posts: 55
    edited 2006-01-16 - 18:47:41
    So far I haven't gotten any technical data.· I only have the manual and a burnt out ROM chip.·It seems not many people have these things unfortunately.

  • T&E EngineerT&E Engineer Posts: 1,396
    edited 2006-01-17 - 21:43:30
    I have a post or two showing how to conect a LED matrix to a series of 4017 and 4081 IC's (cascaded) to create a moving display sign with a BS2 / BS2px and an SX-28. I have attached the drawings.
  • Maniac PonyManiac Pony Posts: 3
    edited 2006-11-28 - 16:25:04
    Hello all, judging by the last posts here everyone seems to have given up all hope of finding the mystical software...... however·-

    As if by magic, lurking on a random hard drive here it is in all it's glory! As yet I haven't managed to get my sign working due to not having the right cable and the exisitng one being plastered into a wall at a very inconvenient location. However I would be grateful if anyone has the manual and they could post that online or send me a copy

  • JagsJags Posts: 4
    edited 2007-01-11 - 00:38:03
    Hello ALL,

    I just obtained·a Rc880 led sign (CPU Version 2.0)·and browsed the internet for info. It seems that not much is available.··I got the sign because I like to tinker electronically smile.gif· and I do need some info like:

    1. Manual, cable configuration, software, etc .... but I'll settle for item 2 only.

    2. What is the power supply output voltage?· I can use a 15V 5A Power supply that I have since a 5V regulator keeps the CPU happy, but it seems that the TIP 126 transistor collectors get the full input voltage from the PS.
    This voltage is then applied to the LEDs, so I really need to know the volts output of the Power Supply.

    A phone jack seems to be the RS232 programming connector.· One of the wires is open, one goes to ground, one goes to a bus driver output (74LS244 IC-9 pin 12) and one goes to what appears to be a level shifter and goes to a bus driver input (74LS244-IC9 pin 13).· Does the RC880 output data to the software via RS232?· The output from IC-9 could be a signal level to the software that a sign is connected ????

    I downloaded the files provided by Manic Pony, thanks Mac. I'll try it out as soon as I get the PS voltage info.

    By the way, the place I got this sign has at least 4 more available, w/o PS or cable.· I think·these RC880s·only have red leds.

  • Maniac PonyManiac Pony Posts: 3
    edited 2007-01-11 - 08:47:25
    Hmm, I thought the rc880 was just a colour model, but I could be wrong due to the lack of decent info available.

    I'm struggling with getting mine to work as I don't have the cable. Ours was wired through a telephone system, so·the end of the·data lead had been cut off and wired to a twisted pair and sent to a phone socket in another office where they·used to run the software, suggesting that it only needs a send and return to control it. Having used a modem output and a variety of different configurations / bit rates I'm still getting no response from the sign as I don't have the original control computer or pc to phone socket link.

  • JagsJags Posts: 4
    edited 2007-01-12 - 03:10:01
    In my previous post I stated that the TIP126 collectors got the full power supply voltage ... I was wrong confused.gif .
    The collectors go to the LED rows and the emitter gets the regulated 5V.· I connected my 15V power supply and the sign displayed .. something.. it seems to be going through the ROM data since it displays some graphics sometimes ..(steaming boat).
    Well, it's a start.·· I ran the program I downloaded and found that it outputs serial data to COM1 or COM2, selectable.· At the top right corner it displays the com port and the baud rate (300).· The output is at RS232 levels so the board input does have a level shifter.
    Wire inputs to the board: yellow=serial data in, red=gnd, black is output from board at logic level, not RS232,
    green is open.
    When I send a message with the software, I can see that data output at the PC RS232 pin 3 (db9 connector).
    I have to make a cable, using the above info, to see what role the output from the board plays. I suspect it may be a DSR signal, but if it is required, why does the software output data with no signal at the DSR pin ???
    More questions!

    I'll post my findings later.
  • RickBRickB Posts: 393
    edited 2007-01-12 - 15:53:42

    Where did you get your sign? URL?

  • JagsJags Posts: 4
    edited 2007-01-13 - 04:40:20
    Well, it works!
    I made an interface cable to connect to the sign, as in my previous post. I ran the software, made a message and downloaded to the sign. When the sign receives the message it scrolls 'RC880' and then displays the downloaded message. I tried the 'colors' commands, but my sign only has red leds... but it's OK.
    The input power circuit has a bridge rectifier at the input, so it seems that the original power supply is AC output of at least 12V and after rectification it feeds into the 5V regular (LM7805).
    A 8K SRAM chip holds the messages and has a backup battery of 3.6V.
    I did not see any data out of the IC9 chip, so it's a mystery what it does .. any ideas anybody?

    That does it for this sign.
  • ysterbalysterbal Posts: 4
    edited 2007-01-14 - 07:32:59
    I do apologize for kinda falling into the middle of this,
    but I managed to get my hands on one of the devices and have to an extent got some code together in C# to work with the device all expect for the FUNC key.

    The manual does not indicate a character code for the FUNC key, its rather a pain as I have am writting a module to read data out of an XML file and present it to the device, for no particular reason other than I can.

    Any help on this would be appreciated.

  • JagsJags Posts: 4
    edited 2007-01-14 - 16:03:56
    Hello ysterbal,
    Can you clarify your post a little?
    Have you written software in C# to program a RC880 sign and if so, would you mind sharing it?· There are several people on this forum that are looking for software & manual for the RC880.

  • ysterbalysterbal Posts: 4
    edited 2007-01-16 - 00:18:00
    Yeah I got my hands on a RC880 friday and an old manual after pulling an interface cable together and spending most of friday and saturday playing with it. I now have a C# class that gets me talking to the device, I will gladly share it, can I post it to the forum directly?

    Also managed to resolve my issue, the real reason for my initial post, so the graphics are all available[noparse];)[/noparse]

    Just one thing I am not the worlds best coder, I know enough to get me around so note it could be cleaned up and improved a million times over I am sure.

  • BeanBean Posts: 7,967
    edited 2007-01-16 - 02:18:45
    By all means, please post it directly in this thread.
    Don't worry about what it looks like, if it works we will appreciate it.
    And if it works, you are a better C# programmer than me [noparse];)[/noparse]


    Cheap used 4-digit LED display with driver IC·

    Low power SD Data Logger
    SX-Video Display Modules
    Stuff I'm selling on ebay

    "USA Today has come out with a new survey - apparently, three out of every four people make up 75% of the population." - David Letterman
  • ysterbalysterbal Posts: 4
    edited 2007-01-16 - 03:23:16
    Ok here goes, the first attachement is just the C# class, note this is .NET 2.0 but it could be retro fitted to .NET 1.1 using the MSComm control. The second is a sample project I was working on "The whole reason for me messing with this thing" the project is really basic its meant to read an XML file presenting the current weather conditions and present it using the RC880 its simple and not complete as of yet but it will give you an idea of how the class works.

    Hope it helps someone, [noparse];)[/noparse]

  • Maniac PonyManiac Pony Posts: 3
    edited 2007-01-19 - 14:33:49
    Please ysterbal post the manual if you can.
    I'm still having no luck with mine. I have what appears to be the original cable which has (from left to right looking on the metal pin side) Yellow, Green, Red and Black in that order. It makes sense that it only needs the red and yellow to work, as they were the only two previously connected up. I suspect it may be to do with the fact I'm trying to use a USB to serial adaptor rather than a proper serial connection.. Oh the irony of modern technology - I have loads of laptops, but they're all too modern!
  • ysterbalysterbal Posts: 4
    edited 2007-01-19 - 18:31:53
    Ok guys here it is pure scan no fancy re-assembling [noparse]:([/noparse] sorry.

    All RC880xxx.png pages are front of scan and RC880_xxx.png back of scan.


  • bigdaddybigdaddy Posts: 1
    edited 2007-04-07 - 18:03:52
    Hi guys, i maybe a little late on this topic, however i have a rc 880 and i need a copy of the manual. i tried the link in the last posting however it did not work. could someone repost the link/files. please.

  • Swap_FileSwap_File Posts: 1
    edited 2007-12-24 - 20:55:00
    A few years ago I made a program in visual basic to program a RC880 sign.

    It includes the full source code, and can control just about everything on the sign (Except passwords)

    Thanks a lot for uploading the manual, ysterbal. I will need to look through it and see what I all missed. I did not have the manual, and had to figure out how to program my sign by mashing buttons in hyperterminal. [noparse]:)[/noparse]

    Post Edited (Swap_File) : 12/24/2007 9:07:49 PM GMT
  • salehsaleh Posts: 1
    edited 2008-07-02 - 14:03:26
    Spankophile said...
    Hi There!

    I'm pretty late to this party it appears!

    I have an RC880 sign + power supply, but no remote :-( Was anyone able to get pinouts/manuals/software for controlling this thing? And if so, would you mind passing it along?



    Dear Mike
    I'm working on new interface for this sign in windows Xp/Vista. as soon as i finished the software I let you know
  • huskernuthuskernut Posts: 3
    edited 2008-08-07 - 03:03:36
    I visited here last fall and learned a lot, looks like this thread is still open. I had very good luck running my RC880 with the netc880.exe program. Now I picked up the bigger display RC8196. I have the original program, at least some of it. I had to download bits and pieces dll for example and each time I got the program to run a little further but now I am stuck looking for a visual basic element called circle2.vbx Any idea where to find that?

    I can provide what I have of the original CREE software. I am not a programmer, I suspect this ran great on a windows 95 machine but is now missing things that might have been part of that build, or I am just full of it.

    has anyone tried to run netc880 on any of the other models?? This is a 5 foot display and works great from the remote but I really want to run it from my PC. Have not had time to try the netc880 on it. the netrc207 program worked on all of their models though. Thanks for any input
  • huskernuthuskernut Posts: 3
    edited 2008-08-07 - 03:40:04
    Follow-up. the help file states The following are system files that are installed in your windows system
    directory: so circle2.vbx must hve been part of older windows system maybe even 3.x

  • K WolfK Wolf Posts: 1
    edited 2008-10-19 - 01:50:04
    I came across this thread while looking into the history of Real Color Displays Inc. I have nearly finished a C# app that someone apparently already beat me to- It displays weather information from's XML feed... Cool!

    There is a yahoo group called colorcells that has all of these downloads (interface app, user manual in pdf, etc.). I will be posting my application there in about a week when it's complete.
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