Multiple DMD's on arduino

The Dot Matrix Display (DMD) is a 32x16 array of high-brightness LEDs for visually striking effects. [Product Page]
Post Reply
debenham
Posts: 33
Joined: Tue Jan 10, 2012 3:22 am

Multiple DMD's on arduino

Post by debenham » Thu Mar 22, 2012 3:44 am

Has anyone had any success with using 6 or more displays on a normal arduino328?
It works fine for me with 4/5 displays but as soon as I add the sixth things start getting messed up.
I'm thinking that the arduino is running out of RAM but it is hard to figure it out

debenham
Posts: 33
Joined: Tue Jan 10, 2012 3:22 am

Re: Multiple DMD's on arduino

Post by debenham » Thu Mar 22, 2012 4:24 am

Okay - ignore that last post.
Turns out the problem was that the writing by SPI was taking longer than the time between interrupts.
Increasing the time between interrupts was not possible (since it made things flicker) but I found out I was able to speed up the SPI writing by a factor of four!
This just needed me to change SPI.setClockDivider(SPI_CLOCK_DIV128) to SPI.setClockDivider(SPI_CLOCK_DIV32) in DMD.cpp
I now have scrolling text working quickly/well on six displays (in either 6x1 or 2x3 layout :) )

Post Reply