help with cadsoft and rgb multiplex idea

Using Arduino LEDs and Multiplexing
1

Hi im a beginner in electronics, so please bear with me since im newbie =)

First, if anyone is proficient in eagle, do i make a part TLC 5940 or can i find a library somewhere that has this.

Ok my idea is that im trying to do an 8x8 rgb led matrix that will use 2 x TLC 5940 to drive the RGB rows of the matrix.

I want to supply voltage from the arduino is it possible to supply from usb?

What's the idea behind using source driver on the anode row, i thought anodes connect to ground?

sorry for all these questions but I really want do a cool pwm 8x8 rgb led matrix circuit.

2

When multiplexing or charieplexing, you need to control both the anode and cathode to light LEDs individually. You will need to control 8 and 24 pins, if you want to use the 5940, you need to control the cathodes with that(they dont work on anodes), so you should be setting up your LEDs for common anode. The anodes you could control right off the arduino(8 pins), or from a shift register.

There are there are lots of examples that you could just copy from.

3

This project is in effect an 8 x 8 RGB matrix using three TLC5940s
http://www.thebox.myzen.co.uk/Hardware/Hexome.html
This is better than two as the LEDs are on for a longer time.

i thought anodes connect to ground?

No anodes are connected to the positive.

4

are there enough pins from the arduino to hook them up directly to anodes?

I seen the idea of hooking the UDN2981A, but another guy recommends M54564P since it has a faster turn-off delay to avoid ghosting.

http://arduino.cc/forum/index.php/topic,18464.15.html

whats the idea of hooking the source driver to the anodes?

when you can directly hook them up to the atmega chip in the arduino to control them?

5

If you plan to work with Eagle, I recommend the SparkFun Eagle library, and the AdaFruit Eagle library. They have many parts that will be helpful in your projects. Also, newark.com has libraries for some parts.

6

whats the idea of hooking the source driver to the anodes?

when you can directly hook them up to the atmega chip in the arduino to control them?

So you can do multiplexing.
When you directly hook them up to the arduino there is not enough current to drive them.

7

ok for the eagle cadsoft part

I am trying to find a library that has M54564P but i cannot find it

is there a chip that i can use in eagle that has a similar structure as this one?