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Do you have a question on Embedded electronics and controls? Ask our Expert, Paul Clarke

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Paul Clarke

Paul has 20+ years of working as a digital electronics engineer and has strong software skills in assembly and C for embedded systems. Currently developing embedded electronics for thermal management control solutions for the air movement industry (HVAC & RAC).




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  • Hello Paul,

     

    I have question for the M27C512-12F1. 

     

    Is it possible to retrieve the programming from the chip to understand the current process?
     
    During a recent building migration from one building to another a series of LED message boards where found, I want to update the system.  However, my knowledge and skill of electronics is minute. I know it could be a ambitious project.  I believe it would be great learning experience to update the system to use .NET Micro Framework on embedded system board to generate the messages.  The message would be updated using XeeBee wireless connection.  Nevertheless, I am getting ahead of myself.  The first task is to understand how the LED panels are controlled.
     
    The display sign employ 4 set of LED panels with each consisting of 12 (2 rows 6 columns) PARA LIGHT C-5580SRD (5 x 8).  Each panel is powered by 9 volts and daisy chained by 10 wire connection.

     

  • in reply to Former Member

    Hello Steven,

     

    Googling suggests that the M27C512-12F1 is an EPROM. It's meant be read - so all you need is the data sheet. Of course reading the EPROM in a system won't get you far - you would need to know what the processor was and a full schematic as well. Can't you find the manufacturer of the panels and ask them how to use them ? Alternatively can you post some photos of the panel controller.

  • in reply to michaelkellett

    Hello Michael,

     
    First, I must say “Thank You!” I appreciate you taking the time helping me understand. I should have realized that just reading the custom ROM would not provide all the answers.
     
    I have tried to locate the company of the DIGITAL-FAX unit without much luck. It seems the unit was built in 2000 (discovered from documentation for wiring a compute to the unit).   I took a series of photos and iPhone video of the controller and a display board. They can be reviewed at http://gallery.me.com/stevenulbrich/100040
     
    More Historical Information
     
    After searching, all I could find is the diagrams for connecting a dedicated PC to the message board.  The display is divided in to section a 3panels area for message and a single panel for a clock. The units receive the updates from a dedicated application install on a computer, then transmitted over a DB9 COM port (converted to RJ11 4-wire).  I created a simple diagram of the how the controller and LED display matrix panels are connected  (LED Message Board Overview).
     
    Steven
Reply
  • in reply to michaelkellett

    Hello Michael,

     
    First, I must say “Thank You!” I appreciate you taking the time helping me understand. I should have realized that just reading the custom ROM would not provide all the answers.
     
    I have tried to locate the company of the DIGITAL-FAX unit without much luck. It seems the unit was built in 2000 (discovered from documentation for wiring a compute to the unit).   I took a series of photos and iPhone video of the controller and a display board. They can be reviewed at http://gallery.me.com/stevenulbrich/100040
     
    More Historical Information
     
    After searching, all I could find is the diagrams for connecting a dedicated PC to the message board.  The display is divided in to section a 3panels area for message and a single panel for a clock. The units receive the updates from a dedicated application install on a computer, then transmitted over a DB9 COM port (converted to RJ11 4-wire).  I created a simple diagram of the how the controller and LED display matrix panels are connected  (LED Message Board Overview).
     
    Steven
Children
  • in reply to Former Member

    Hello Steven,

     

    You now have a few options:

    1) if you have access to the PC application you could connect a panel to a PC and watch the RS232 traffice between the two and perhaps decode the protocol.

    2) the processor is a Z80 so you could get a set of development tools and try to reverse engineer the code  - this will be between difficult and very very difficult depending on how the code was written.

    3) reverse engineer the panels (so you can work out how to drive them) and make your own controller from scratch using modern parts - this might be the easiest.

    4) put a bit more time into trying to get hold of the original control protocol.

     

    If I were you I would spend a day or so on 4 and if that failed go for 3. The panels don't seem to have a processor so you should be able to figure out how they work.

     

    MK

  • in reply to michaelkellett
    Hello Michael,
    Well this is going to be a great adventure. I hope that not a remake of the Odyssey.  I will try to reverse engineer the controller with up to date parts.

     

     

    Now, I have to start learning more and more.  I have decided to purchase some up to date component to help me learn the process.  SURE Electronics is offering a Demo Driver Board for 0832 Dot-Matrix Board can be used with the P4 32X16 RG Bicolor LED Dot Matrix Unit Board SPI.
     
    Do you have recommendations?
     
    Steven
  • in reply to Former Member

    Hi,

     

    I was able to use a different controller board to light up the LED Panels (Clock and Message) with the start up routine.

     

    Detail Images of the LED and Controller Boards - http://www.flickr.com/photos/sju-apprentice/collections/

     

    The Active Message Board section has a AVI showing the message boards

     

    With the controller board working is there a way to capture and understand how the LED panels are being controlled?