TLC5920 Question

Hello Everyone,

I am planning an upcoming project that has a ridiculous number of 7 segment LED's, 64 to be exact. After researching how to control this mess I have settled on using a n X 8 matrix with a LED driver. The LED driver I would like to use is the TLC5920. I even found a project that uses one with an Arduino for reference.

The only real stumbling block for me is the datasheet gives a value of 10MHz for the clock in on the chip, but the Arduino runs at 16MHz. Is this going to be an issue?

EDIT* It seems I have put this in the wrong channel, but it doesn't appear that I can move it.

8 MAX7219s would be easy. Might even be able to use the Parola.h library.
Just writing to the 8 address registers on each chip would also not be difficult.
Give each it's own chip select if you have the IO pins:

digitalWrite (ssPinX, LOW); // X = chip 1 to chip 8
SPI.transfer(registerAddress); // 1 to 8 for each chip
SPI.transfer (dataToDisplay); // Can be 0-9, H-E-L-P if use built in decode mode, or do your own mapping
                                             // with fontArray[dataToDisplay]);
                                             // or have an array for each chip even fontArray{dataToDisplay[(X*8)+registerAddress)]]);
                                             // where 1-8 is one chip, 9-16 is the 2nd, 17-24 is the 3rd, etc
digitalWrite (ssPinX, HIGH);

Maybe ssPin = {list of 8 IO pins};
Then call a function with maxchip from 1 to 8, registerAddress from 1 to 8, and the data and use ssPin in the above.

Yes, I looked at the MAX drivers and do agree that it would be a fantastic choice. The issue I have is they are quite pricey and I plan on building a number of these.


$2 each from
MAX7219 7 Segment + Dot Point, Common Cathode serially interfaced display driver PDIP-24
Need a 0.1uF cap, a 10uF cap, and a 10K or so resister per chip to set current limit for the IO.
Are you making a PCB also? That could save a lot of time in assembling boards.

TLC5920 are SMD only, cost more for 16 output devices
and unless you add more hardware to handle multiplexing the 16 outputs across more than 16 LEDs (the MAX7219 handles 64 LEDs in groups of 8) you will need 32 chips, vs 8 MAX7219s.

You are a life saver, I never thought of looking on Tayda. The Mouser price is North of $10. I would prefer a SMD package, but I can get creative with the PCB design most likely. Thanks again.

Sometimes the SMD are more trouble, especially when having to route a lot of signals. You run out of places to squeeze them thru.

Yes, the official prices at Mouser and Digikey for these parts are pricey. These are the only active components that I buy that are not from Digikey, Mouser, Arrow, Avnet, or other reputable US distributors. And FTDI modules from Haven't had an issue with 1 yet.