hooking up an 8x8 with a max7219

there is not one place where i can find that states how do directly hook up an 8 by 8 led matrix to the max 7219. They all tell you in the schematic of the matrix what too hook up, but they don't get that the wires are not the way the schematic is! Can somebody please tell me how to hook up the two rows? and some code please?

sorry if i'm being testy, i just tried pulling the matrix out while attemting to wire it correctly, and stabbed myself with 3 of the wires from the matrix... and also bent the whole row.... so im gettin mad of trying to hook this thing up. from what i have right now, only some rows with some lights are on, so it's obviously not working.

any help apreciated, thanks

Hi,

there is not one place where i can find that states how do directly hook up an 8 by 8 led matrix to the max 7219. They all tell you in the schematic of the matrix what too hook up, but they don't get that the wires are not the way the schematic is! Can somebody please tell me how to hook up the two rows? and some code please?

sorry if i'm being testy, i just tried pulling the matrix out while attemting to wire it correctly, and stabbed myself with 3 of the wires from the matrix... and also bent the whole row.... so im gettin mad of trying to hook this thing up. from what i have right now, only some rows with some lights are on, so it's obviously not working.

any help apreciated, thanks

I don't really understand what you actually want to know. Something like this ??? http://www.arduino.cc/playground/uploads/Main/MAX72XX_Schematic.jpg taken from this article : http://www.arduino.cc/playground/Main/MAX72XXHardware If you are asking for a specific matrix, well you know there is no The Matrix and how to wire it. About every maker of LEDs on this planet sells them packed into matrices each one with his very own layout for the pins to drive them.

If you use a DIY matrix you should wire it the way shown in the schematic. If you bought a matrix from a shop we would at least need a link to a datasheet for the matrix to help you to get the wiring correct.

Eberhard

Exactly. All the websites show you how to connect the rows and columns to the pins on the MAX chip. It's up to you to determine which pin represents which row or column on your matrix.

ok, i have a datasheet to show you, and as far as i thought they were all the same… heres the page with the datasheet:

http://www.futurlec.com/LED/LEDM88G.shtml

i’m just uber confused…

p.s don’t get the matrix frothere, it’s TINY SHRIMPY… bearly measures an inch by an inch… shoulda looked at the specs lol

Yep so now you have all the information you need. From the matrix datasheet, you can see that row 1 is connected to pin 9 of the matrix. Now connect pin 9 to the pin of the MAX corresponding to row 1.

Are you sure you have got the pin orientations correct? It's not as easy to identify which is pin 1 as on a standard IC. As shown in the datasheet, look at it side on with the side with the part number printed on it facing towards you. Pin 1 is then the leftmost pin on the closest row.

I have a number of these matricies, and I think they are excellent - I think you SHOULD get them from there. They are excellent for representing a large amount of data in a small size, they are reasonably bright and VERY cheap.

ok, i understand what you mean and i think i’ll be able to hook it up now…

when i said not to buy them from there, i meant that i bought it from there and expected a much larger matrix. I don’t think they stressed enough that this is a very small matrix…

by the way, what code should i use to make a scrolling screen? if it can be simple, i’d love it, becuase i suck at coding :slight_smile: thanks!

JUST ONE THING:

what do they mean by pin 1, and then there is a 9 in the circle? Do i hook up pin 1 to row 1 on my max chip?

i’m confused all over again. where it sias pin 1, then to the right of it is pin 2, and then pin 3 and on? or are they out of order? and then on the other side of pin 1 is pin 9? or pin 16?

so if this is a top view of the pins, lol sorry work with me:

What pin is that?
|
. . . . . . . .

. . . . . . . . _ which pin is this? 8?
|
Thats pin 1

I'm pretty sure the pin order works the same as an normal IC.

So if you were looking from the top, as if you could see the pins trough the LEDs, with the side with the writing to the left:

1 16 2 15 3 14 4 13 5 12 6 11 7 10 8 9

It's pretty clear on the diagram, you just need to remember that the pin order has nothing to do with the row order. I totally agree that it would have been sensible for the manufacturers to make it row 1 = pin 1, row 2 = pin 2, col 1 = pin 9, col 2 = pin 10 etc, but they haven't. There must have been some de facto standard, because most manufacturers use the same crazy pinout.

So as the diagram shows, row 1 of the LEDs is connected to pin 9, column 1 of the LEDs to pin 13 etc.

How about YOU write the code for scrolling text and post it here for us to use!

lol trust me, if i could i would, i was just asking if there was a pre made code that's a standard for scrolling code. if i knew how to code well, it would make my life alot easier, but all the books and references don't really seem to help, but w/e i'm not in college yet so no worries

lol trust me, if i could i would, i was just asking if there was a pre made code that's a standard for scrolling code. if i knew how to code well, it would make my life alot easier, but all the books and references don't really seem to help, but w/e i'm not in college yet so no worries

Coincidently I'm working on scrolling with a 7219 matrix at the moment. Not my highest priority though, so don't expect anything.

ok, no rush. But the matrix still isint working…

so this is exactly how i hooked up the matrix:

this is a top view of the matrix with the writing on the side is on the left side:

0 G
1 F
2 E
3 D
4 C
5 B
6 A
7 DP

the code is from the playground, and i added no capacitors, i only have one resistor on rset, that connets to vcc. and just pretty random lights are on. seems like the chip is stupid, i upload, and it doesent change, i reset, it doesent change, i turn it off and on, doesent change… nothin…

ok, no rush. But the matrix still isint working....

so this is exactly how i hooked up the matrix:

this is a top view of the matrix with the writing on the side is on the left side:

0 G 1 F 2 E 3 D 4 C 5 B 6 A 7 DP

the code is from the playground, and i added no capacitors, i only have one resistor on rset, that connets to vcc. and just pretty random lights are on. seems like the chip is stupid, i upload, and it doesent change, i reset, it doesent change, i turn it off and on, doesent change... nothin....

Sounds like you don't have it connected up correctly. I don't know what you are trying to say in the diagram you have written out.

If I were you (and this is exactly how I did it when I was setting up my matrix) I would take it in steps.

Step 1, hook up 5 lines between the arduino and the max7219. +5V, GND, Din, CLK, LOAD. Connect resistor between ISET and +5V.

Step 2, Connect an ordinary LED across the MAX7219, anode to MAX7219 pin 22, cathode to MAX7219 pin 2

Step 3, Upload this sketch to make sure you have the connections right between the arduino and the MAX7219. Remember to change the pins to reflect where you have got the Din, CLK, LOAD pins connected to.

#include "LedControl.h" 

//LedControl(int dataPin, int clkPin, int csPin, int numDevices);

int cs_pin = 10;
int data_pin = 11;     //CHAGE THESE NUMBERS AS NECESSARY!!!!
int clk_pin = 12;

LedControl lc=LedControl(data_pin,clk_pin,cs_pin,1); 

void setup() { 

  lc.shutdown(0,false);
  lc.setIntensity(0,15);
  lc.clearDisplay(0);

} 

void loop() { 

  lc.setLed(0,0,0,true);    // Turn on the matrix row 0, col 0
  delay(500);               // wait a bit
  lc.setLed(0,0,0,false);    // Turn on the matrix row 0, col 0

}

The LED should flash at 1Hz, just like the hello world sketch! Unplug the LED, connect it across any two other random pins (not the data or power pins) and it should not light up.

If you can get that working, then you can go onto connecting up the rest of the matrix.

could i have killed my max chip? because there seems to be no logic going through, just lights on when batter is connected...

Of course you could have, but seems a lot more likely you aren't connecting it up propoerly or sending correct commands

There is a problem with your loop-method.

You
light up the led;
wait for 500ms;
switch the led off again
ok so far, but as the name of the method suggests, it will loop again immediatly, so the LED gets switched again without really being off

Try this

void loop() { 
  lc.setLed(0,0,0,true);    // Turn on the matrix row 0, col 0
  delay(500);              // wait a bit
  lc.setLed(0,0,0,false);    // Turn on the matrix row 0, col 0
  delay(500);              // wait a bit while its off
}

Eberhard

Good point - copy and paste error.

Thanks for catching it

ok, i'll try that. ill post back soon with results! thanks for the help