5x7 dot matrix display project?

wilsoe

I have searched for this I promise.··For at least two days.· You·can laugh all you want but when you are done·could·you please point me in the right direction.

I am looking of an example project using 5x7 dot matrix displays.· I would like to multiplex four·displays.· Is this possible?· I have looked at the Maxim max6952 and max6953, but even there app notes do not seem it help.· Does anyone know of an example that would help to explain this more.· Also, if there is another method that would be great because the Maxim drivers seem to be hard to find.

Thanks

Jonathan

Wilsoe,

I just happened to have written some code that drives two 5X7 displays using the MAX6953. It requires a BS2P, because it uses the STORE command and the I2C command. It has a variable width font, which is stored in the second slot. It can easily be made to drive four digits.

HTH,

Jonathan

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www.madlabs.info - Home of the Hydrogen Fuel Cell Robot

Bean

wilsoe,
I don't think anyone will laugh at you.

If you've spent 10 minutes with google and 10 minutes searching this forum and you cannot find the answer than ask away.

That's my feeling anyway...

Bean.

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·

wilsoe

Where did you purchase the MAX6953 from?· Mouser, Newark in one, Jameco, and Digi-Key do not·seem to have them in stock.· Also, do you have schematics or a picture of your project to help visualize the process.

Thanks

wilsoe

Bean,

I know what you mean.· But I though I would get burned with lots of examples that I could not find myself.· I always hesitate to ask for help and it ends up taking me allot longer to learn something basic.

Thanks

Paul Baker

goto digikey, type led driver maxim into the search dialog to see what LED drivers are commonly availible, youll see they do have the MAX6954 (also thier most expensive), be sure to get one that matches your matrix (common anode or common cathode).

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Tom-Matrix Orbital

What kind of of displays do you plan to use? If you are using more than one on the same bus you can use Matrix Orbital displays set on I2C mode. You can go to www.matrixorbital.com/ for the selection. Sample code for the displays interfacing with the stamp can be found at www.matrixorbital.ca/appnotes/basic_stamp/

wilsoe

Paul Baker,

I checked out the app notes for the MAX6954 and it·looks like it is·designed for 16 digits 7-segment, 8 digits 14-/16-segment LED·displays.· This is the same problem as before I really do not understand how to use this on a 5x7 dot matrix display.

Thanks

Jonathan

Wlisoe,

I actually got my 6953 as a sample, so I don't know where to get one off hand. I don't have a schematic, I just used the MAX app. note and the display data sheet. If you have any problems with the connections, let me know. I very much reccomend breadbaording this project first to get it all runnning. If the code doesn't make sense, let me know and I'll do what I can to explain.

Jonathan

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www.madlabs.info - Home of the Hydrogen Fuel Cell Robot

Clock Loop

Couldn't you start with something a bit simpler?

Using a few 74hc595's to drive your dot matrix display?

Forrest

There's an interesting article in the March, 2005 issue of Nuts & Volts titles Side-Scrolling LED Display at www.nutsvolts.com/toc_Pages/mar05toc.htm

The project uses (10) 5 x 7 LED array's driven by (10) 74HC595 shift registers and (5) 2N2222A transistors using a Gameboy's serial port running at 512 KHz.

Note the article is not on-line - you'll need to purchase the back-issue

wilsoe

Jonathan,

I also just·asked for a sample.· I was just wondering where to purchase.· I guess you are right to just try from the max app notes.· But I was just looking for a sample application,·schematics or descriptions.· I guess I am spoiled with the Parallax books.

Thanks

Jonathan

Wisloe,

It's easier than it looks. While there are many connections, they aren't that hard to figure out. I like the MAX6953, it has some nice feature like dimming that you don't get if you use shift registers. For example, I have a CDS cell on my sign, it auto dims the sign at night, at makes it brighter during the day. You can also use it on bi-color displays. Let me know if you have any problems, I'd be happy to help.

Jonathan

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www.madlabs.info - Home of the Hydrogen Fuel Cell Robot

Paul Baker

I broke down and searched 20 distributors for you, wasn't hard just typed the part number into www.findchips.com while they are not all of the online distributors, they are all the major ones. Sorry to say but digikey is the only one to sell them, and they sell them in min 10 pcs for $185.4 for the lot. To purchase in smaller quantities you have to buy them directly from Maxim http://shop.maxim-ic.com/

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Steel

I did create a similar project to yours.· It was 4 5x7 LED matricies powered (just for functional test) by 3 74HC595.

Because the LED's are in a Matrix, you need to scan one line at a time.· I created a program to fill the EEPROM with a pattern (In this case, a "$") and display it one line at a time on the LED display.

Since the Matrix is 10x14...The first 74595(or LED driver) drives the first 8 Rows.· The second 74595 drives the last 2 rows, and first 6 columns.· The third 74595 drives the last 8 columns.

the code is attached.