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Programming Questions & Help >> Programs >> 4x8 led matrix
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Message started by mga on 10/09/07 at 00:02:06

Title: 4x8 led matrix
Post by mga on 10/09/07 at 00:02:06
Hi

I am trying to connect a 4x8 Lite-On matrix using the example in http://wiring.org.co/learning/examples/hello_matrix.html but I can't find the schematics. The DigiKey guy is supposed to send the schematics sometime in the future. In the meantime I can see the thing working because some LEDs light up but I'm not sure how to connect the rows/columns (this display has two rows of 8 pins) so the 7219 does its job.

Any suggestions?

This is also a orange/green matrix. How is this handled?

Thanks

Mauricio


Title: Re: 4x8 led matrix
Post by mga on 10/10/07 at 18:41:19
thanks

here's the datasheet in case anyone needs it: http://aeon.uniandes.edu.co/mga/LTP-23548AA-NB.pdf

Title: Re: 4x8 led matrix
Post by Alan_Kilian on 10/12/07 at 22:37:42
Your LED display has a different pinout than the example.

Try connecting it like this:

LITEON display pin #    MAX7219 pin #
Cathode                           Digit
    1 ------------------------- 2
    2 ------------------------- 11
    3 ------------------------- 6
    4 ------------------------- 7
    5 ------------------------- 3
    6 ------------------------- 10
    7 ------------------------- 5
    8 ------------------------- 8

Anode                            Segment
     9 ------------------------ 14
   10 ------------------------ 16
   11 ------------------------ 20
   12 ------------------------ 23
   13 ------------------------ 21
   14 ------------------------ 15
   15 ------------------------ 17
   16 ------------------------ 22

Title: Re: 4x8 led matrix
Post by mga on 10/13/07 at 23:51:01
hey thanks!

i wired it as you specify but get no response...


Code:
Matrix myMatrix = Matrix(24, 26, 25);

void loop()
{
 myMatrix.clear();
 delay(1000);
 myMatrix.write(1, 1, HIGH);
 delay(1000);
}


i also tried with a sprite. i used to get (with the tutorial wire setup) irregular (although unchanging) led lighting. now the thing doesn't light up at all...  do all other wires go as they show up in the tutorial?

thanks a lot!

- mga

Title: Re: 4x8 led matrix
Post by Alan_Kilian on 10/14/07 at 02:18:49
I notice you use pins (24,26,25) and the example uses pins (0,2,1).
Where do you have the wires from the MAX7219 connected to the Wiring board?
Did you move them from 0,2,1 to 24,26,25 during this re-wiring?

Can you hook up a single LED to ROW-0 and COLUMN-0 and get it to
light using the matrix library?

We'll get there one step at a time.

Title: Re: 4x8 led matrix
Post by mga on 10/15/07 at 02:05:25
thanks!

yes, pins 24, 25 and 26 are connected (other pins are in use but not in that particular program)

will try the single led in 0,0 and will get back to you... not in the lab so can't do that until tuesday :(

thanks again

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