Looking for some advice for 8x8 RGB Led matrix driver

Hello Eduardo,

The decision which part fits your requirements best is dependent on the requirements you have in your system. For example is your controller fast enough to drive all 24 channels in series. If the controller is not fast enough to drive the 24 channels in series then you should have a look on TLC5951 which gives you 3 serial interfaces for 8 channels each. Then the controller needs to drive 3 interfaces, but just in 1/3 of the speed.

If you need open/short detection on the LEDs, TLC595x are the right parts.

What current do you need per channel?

So if you open the datasheets of these 3 parts and have a look on the bullets on pages 1 than you might already be able to decide which part is the right one for your application. It really depends on what you want to display in which speed with which accuracy to decide which part is the right one.

Best regards,
Brigitte

Hello Brigitte, thanks for the quickly answer.

I don't know if I'm allowed to publish external links, I didn't find about this in the terms.

This is the matrix data-sheet: http://www.seeedstudio.com/depot/datasheet/2088RGBMatrix.pdf

The atmega for example has one SPI channel, the xtal is 16Mhz, and I can get around 60hz refresh rate to avoid flickering in the matrix. (I've done this with 74HC595 8 bit shift register).

I need 20mA, is a common value for normal led.

I want to display basic animations or text, I have 6 of this matrix, I could do a 16x24 display.

I think TLC5947 could be my choice, it has pwm and I can use one SPI channel. The TLC5952  doesn't have pwm and the TLC5951 needs 3 SPI channels.

Could be right my decision?

Thanks!!

Eduardo.-

Hola Eduardo, que bueno encontrar a alguien de Argentina desarrollando estos proyectos, soy nuevo en el foro y quería consultarte sobre tus experiencias en este circuito ya que estoy por realizar una matriz con estos integrados y recién estoy tomando contacto con esta tecnología. Mi idea es utilizar leds pirañas RGB de alto brillo y utilizar un integrado cada 8 leds. Lo que no tengo en claro es cuantos circuitos podré poner en cascada para no tener problemas con los tiempos del spi.

Hi Eduardo, good to find someone in Argentina developing these projects, I am new to the forum and wanted to consult you about your experiences at this circuit and I'm about to make a matrix with these built and I'm just making contact with this technology. My idea is to use RGB Piranha LED with high brightness and use a device every 8 leds. I have no clear is how to cascade circuits able to avoid problems with spi times.

Holaa, no he avanzado mucho, estoy trabado con el tema de configurar SPI en el micro.
El 5947 tiene 24 salidas, seria uno integrado cada 24 leds, para 16 leds esta el 5940 y para 8 no conozco. Yo me trabe por no saber configurar eso justamente, calcular el refresco del display para saber configurar SPI cada determinado tiempo. En mi caso por las matrices, puedo tener un display desde 8x8 con 1 matriz hasta 16x24 con 6 matrices.

Hi!! I have not made ​​much progress, I'm stuck with setting up the SPI bus.
The 5947 has 24 outputs, you should use one every 24 leds,  for 16 leds you could use the 5940 and for 8 leds I don't know which ic. I get stuck because I don't know how to configure SPI in the micro, calculate the refresh rate of the display to know how to configure SPI every determinate time. In my case, I can have a display from 8x8 with one matrix to 16x24 with 6 matrix.

Thanks Brigitte, I'm going to try and then consult

Best regards,

Amid

claro en mi caso sería un integrado cada 8 leds ya que quiero hacer un panel RGB, lo que no entendí fue como utilizar los integrados en cascada, eso que releí el datasheet como 200 veces.

saludos

Just keep in mind your brightness will suffer in this configuration because of the POV. Also, while it should be fine for an 8X8 grid, I've had problems scaling this solution up to larger grids, like 16 X 16. Flicker and dimness became a large issue there.

To get the maximum brightness from your LEDs, you'll need to use a 5947 on each row, or go with something like the 5970 and stick one on each LED in cascade. Unfortunately, the 5970 is a little too expensive to really do this with, the A6281 (Allegro) isn't quite as nice, but will get the job done for about 1/4 the cost.

I'm researching solutions right now for medium/large scale displays (32 X 32, 64 X 64) on soft surfaces over a medium distance. I was planning to use the 5947, but it just isn't practical to run that many wires around (in my application, because I don't have a PCB), so I need to use a solution similar to this: http://docs.macetech.com/doku.php/shiftbrite. I'm planning to do my own production run of a few thousand of these to start with, and I've been looking for chips comparable to the A6281, the 5970 certainly fits the bill, but are just too expensive. Does anyone have a suggestion on a more affordable TI solution that would do this? I like the 59xx series, I'd prefer to stick with that, but can't pay $5 each (http://www.mouser.com/Search/Refine.aspx?Keyword=tlc5970) to drive a single RGB LED.

Hi Clayton, look www.lumisense.com, they have a 8x8x8 RGB led cube.
That cube is like using 8 matrix of 8x8 in parallel , like a 16x32 display and works with TLC.
I think TLC could be used without any problem. I don't know how to use it lol

Greetings!
Eduardo.-

Hola Eduardo, alegria encontrar a un argentino por estos pagos. Me gustaria saber si pudiste hacer algo al final. Si podes contactarme por mail asi me pasas info util (es para un proyecto de la facu). Avisame y te paso mi mail. Muchas gracias por tu mano por adelantado. Saludos