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Programming help needed for LED display
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Kevin Mullins:

--- Quote from: headkaze on July 30, 2007, 09:07:35 pm ---You will have to look up your device on the Net to find such documents or contact the manufacturer.

--- End quote ---

When you use the term "device" I'm assuming you mean like the micrcontroller and such to run the display right?

The display currently has NO electronics whatsoever..... so the controller will be of my choice and that circuitry will have to be built also. I hava few I still need to check out and see if they are useable for this purpose.

I'll definitly check out the LCDSmartie software..... thanks. My understanding is most LCD displays work "similar" to an segmented LED display....just a much lower voltage. So maybe it can be tweaked to do what I need.

(I really do wish I was a tad sharper on the programming stuff myself)  :P
rockin_rick:
You are going to need a few separate things to get this to work.

First is the juke software.  It is either going to have to send commands out of the PC to your display, or send commands to a helper program.

Second (if needed) is a helper program (perhaps mamehooker).  If the juke software will send out of the PC to the display, you won't need the helper program

Third is an interface from your PC to the display.

Fourth is the display's controller.

Fifth is the display itself.

----------------------------

If you use one of the modules (intelligent display) like I linked to earlier, then #4 and #5 would be all in that module.  The interface would be a serial cable from your PC's com port to the module.  If the juke software can send data out the com port to the display in the format that the display requires, then the helper program is not needed.  If the juke software cannot/does not send data out the com port in a format that the module requires, then the juke software will need to send data to a helper program that can interpet the data from the juke software and send the necessary commands out the com port in the format that the module requires.

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If you want to use a dumb display (which it seems like you are leaning towards), then you need to add some kind of display driver.  This can be either a microcontroller/microprocessor or some other kind of logic and driver ICs.

If you use discrete logic, then perhaps you could design a circuit that can interface the printer port.  You'd need then to have some latches, and decoders to drive the display.  Maybe a 4511 on each digit, etc.  The drawback with this design is the reliance on the printer port.  Most new PC's don't come with one, so most likely a juke software programmer would be reluctant to add a feature that relies on that.  The juke program will also need to directly support your circuitry.

If you want to use a µC, then the software will have to be able to control your display (match electrical specs), and interpet commands somehow.  However it receives data, the juke software or the helper program will have to send data in that format.  This is preferred, as you don't have to rely on the printer port.  This method will allow the greatest flexibility as any interface to the PC can be used.  It sounds like this is what you are looking for.  There may be a "LED interface board" that will accept data and interface to a dumb display, but I don't know of one (but I've never looked).  People/companys that make something like that usually put the LEDs on the board and sell it as a full module...

-----------------------------------------

IMO, using an all in one serial module is your best chance to get the juke programmer to help you out.  If you design a one off circuit, then all his work will only benefit you.  I think that you may have better luck in getting his support if he knows that his work will benefit others/lots.  Most likely, if he spends lots of his time on something, he'd like to be able to add to his feature list.  Not that it's impossible that he'd help you out with just your situation, but your chances are better is all I'm saying.  If you are willing to do most of the debugging/beta testing that may help you, too.  Even more so if you do all the helper program setup/config work.

Good luck - cool project!
Rick


Chris:
That Silicon Craft module looks interesting... I could probably work with that.  I have an LED-Wiz (still sitting in the box), I could try to figure out how to talk to that from C...

I need to get my pending changes tested and released, then I can look at driving external displays.  I have a couple of four-line LCD's to play with and an LED Wiz, and I may be able to get one of those 7 segment controllers when I get paid again, it's only $25.

--Chris
Kevin Mullins:
Just wanted to throw this out there...... I was digging around for those other displays that I have been gathering up for the microcontroller type information , of course now that I'm looking for them I can only find one.
But anyways, here's the one chip that I'm looking at right now and is kinda the idea of what I had in mind of using. But will try to dig up the others later to see what similarities they have.
MM5450N

Which might also work very similarly to some of the modules posted about earlier. http://www.siliconcraft.net/products.htm#SC1602MBS
Anyone check out their software download section, may be something of use there.  ???
http://www.siliconcraft.net/download.htm

Food for thought..... as I'm still trying to understand it completely.
I had been kinda looking into the conroller chips themselves to see if there was a common ground approach that would be more useful in multiple applications. (trying to avoid the "one-off" project)

EDIT: Just found something else of interest to poke around with.
http://www.apogeekits.com/led_display_digits.htm
rockin_rick:
The MM5450N that you linked to would still need a microcontroller to drive it.  It has a serial data input port, but it's not RS-232.  It a synchronous serial input, meaning that it needs a clock signal to time/latch the serial data into it, while RS-232 is asynchronous, without that clock.

Rick

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