I have recieved a sparkfun rgb led matrix as a gift 
My question is how do i control it?
Well, judging by the datasheet... well it required a 20MB chinese font download to display.
There are 32 pins underneath. For a normal array of LEDs (just a single colour), you can multiplex then - so 64 LEDs would be 2 x sqrt(64), or 16. For this tri-colour LED matrix, there are 4 pins per LED, so 4 x sqrt(64), or 32.
I would assume three sets of 8 pins would be rows of anodes, and the last 8 pins would be columns of grounds.
Ah, in their diagram, they have rows for the cathodes, and columns of the anodes.
Could I use Max7219's to control it? i have two right now as samples, so i want to use them in something. Controlling just R & G will be fine for me right now
Hi,
Could I use Max7219's to control it? i have two right now as samples, so i want to use them in something. Controlling just R & G will be fine for me right now
No, your matrix uses common-anode Led's, the MAX7219 works only for common-cathode Led's
Eberhard
I guess the ever so famous TLC5940 would be handy here as well.
Hi,
No, your matrix uses common-anode Led's, the MAX7219 works only for common-cathode Led's
Eberhard
I'm not so sure it's a common anode. From Sparkfun's description . . .
"Description: Triple Color LED Matrix! This large matrix has 64 Red, 64 Green, and 64 Blue individual LEDs built into one common cathode housing. It's a monster to control, but just imagine what kind of colors you could produce by mixing!"
Sometimes the data sheets for these show both models - easy enough to confirm though.
If it is common-cathode (and I think it is) and you want to drive only 2 colors (without fading individual led colors) 2 MAX7219's should work.
There are several threads on that here. Here is one:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1206907547
(and after I promised myself I wouldn't get involved! :-X)
http://www.datasheetcatalog.org/datasheet/fairchild/GMA3688C.pdf
is the datasheet, 
its not a RGB one just bicolor, guess i should look at these things before i post ;D
its common anode, not CC like it says in Sheet
Pin :
| 1 Anode row 8 24 Anode row 1 |
|---|
| 2 Anode row 7 23 Anode row 2 |
| 3 Anode row 6 22 Anode row 3 |
| 4 Anode row 5 21 Anode row 4 |
| 5 Cathode col. 1 G 20 Cathode col. 1 R |
| 6 Cathode col. 2 G 19 Cathode col. 2 R |
| 7 Cathode col. 3 G 18 Cathode col. 3 R |
| 8 Cathode col. 4 G 17 Cathode col. 4 R |
| 9 Cathode col. 5 G 16 Cathode col. 5 R |
| 10 Cathode col. 6 G 15 Cathode col. 6 R |
| 11 Cathode col. 7 G 14 Cathode col. 7 R |
| 12 Cathode col. 8 G 13 Cathode col. 8 R |
Does calling a matrix common anode or common cathode really mean anything? Seems like its both - the rows are common anode, the columns are common cathode.
Does calling a matrix common anode or common cathode really mean anything? Seems like its both - the rows are common anode, the columns are common cathode.
it makes a difference when you want to controll it
Eventually i will want it to Scroll Messages across it
And Play Pong 
i guess i could do it with 74hc595's
Does calling a matrix common anode or common cathode really mean anything? Seems like its both - the rows are common anode, the columns are common cathode.
it makes a difference when you want to controll it
Eventually i will want it to Scroll Messages across it
And Play Pongi guess i could do it with 74hc595's
With only 595's? How is that possible?
Dont u need both anode & cathode?
Im asking because ive been trying to figure out this myself, how to use only the 595's for this, but i still dont know really.
in the link hes using three 74hc595's to control a common cathode matrix i could adjust it to common anode sigh
ah right, ill study that matrix a bit more then. most interesting... i would love to use the 595's, they are easy enough and cheap!
in the link hes using three 74hc595's to control a common cathode matrix i could adjust it to common anode sigh
I thought we established that you had a common cathode display?
BTW the link to the last data sheet doesnt match what I know of Sparkfun matrixes.
If you indeed have a 2 color matrix - "medium" you have -
and the data sheet is
(which may have the same pin outs as your link.)
If the above is true, you can use the 2 MAX7219 chips you say you have. (They don't need to be the MAX7221 & I don't know why - but they work.)
I have used this setup for 2 colors on the matrix and scrolling messages. However I do the scrolling with one color at a time - only because of the complexity of programming in the 2 colors. I also have a two color "bouncing ball" thingy that might help with pong. (The code was somewhere on this forum.)
I can't speak at all for the 595's but if you want to investigate the RG w/ the Max, you can start here:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1206907547
the link to the last data sheet doesnt match what I know of Sparkfun matrixes
i know, i just thought that it was a sparkfun one, the datasheet that i gave you was the right one.
which one would be easier to program ? max7219 or 74hc595?
the link to the last data sheet doesnt match what I know of Sparkfun matrixes
i know, i just thought that it was a sparkfun one, the datasheet that i gave you was the right one.
which one would be easier to program ? max7219 or 74hc595?
BTW i am eventually going to want to make a sheild out of this whic would be the smallest one?
I gotta say, that 595 matrix had me curious.. seems that guy is using a 595 for the GND/row as well, how is that even possible?
As its a powersourcing driver i mean.. judging from the pictures he is using 1k resitors on the 595 chip that controls the GND.. one can say im a bit puzzled.
he uses NPN transistors, when the 595 sources current it turns on the transistor pulling the pin to GND. Thats all he does
As its a powersourcing driver i mean.. judging from the pictures he is using 1k resitors on the 595 chip that controls the GND.. one can say im a bit puzzled.
Ah, thank you! I could never have figured that out.
he uses NPN transistors, when the 595 sources current it turns on the transistor pulling the pin to GND. Thats all he does
As its a powersourcing driver i mean.. judging from the pictures he is using 1k resitors on the 595 chip that controls the GND.. one can say im a bit puzzled.
From what i can understand, he is using 1k resistors, and BC848B NPN transistors, is that right?
From what i can understand, he is using 1k resistors, and BC848B NPN transistors, is that right?
Yes That is correct