## 12 panel display

The Dot Matrix Display (DMD) is a 32x16 array of high-brightness LEDs for visually striking effects. [Product Page]
MrPrezident
Posts:2
Joined:Wed Mar 06, 2013 3:28 pm
12 panel display
I'm working on a project where I plan to use a 12 DMD panel display (4x3). Has anyone built a display that large? Do I need to be concerned about speed? I'm worried that maybe the farthest panel might take longer to update than the closest panel. I need to be able to do some animations.

42n8
Posts:46
Joined:Wed Dec 26, 2012 8:10 pm
Location:Auckland, NZ

### Re: 12 panel display

MrPrezident wrote:I'm working on a project where I plan to use a 12 DMD panel display (4x3). Has anyone built a display that large? Do I need to be concerned about speed? I'm worried that maybe the farthest panel might take longer to update than the closest panel. I need to be able to do some animations.
Someone on here claimed to have done 20. Personally I haven't done 12 yet, but intend to do 16 in the near future.

The hardware propogation delay for the 12 boards will be < 20 microseconds and the max SPI frequency is 20MHz which is 50 microseconds so data's pretty much going to reach the end of the line while the SPI signal is present.

Regards

MrPrezident
Posts:2
Joined:Wed Mar 06, 2013 3:28 pm

### Re: 12 panel display

42n8 wrote:The hardware propogation delay for the 12 boards will be < 20 microseconds
Where did the < 20 microseconds number come from?

42n8
Posts:46
Joined:Wed Dec 26, 2012 8:10 pm
Location:Auckland, NZ

### Re: 12 panel display

MrPrezident wrote: Where did the < 20 microseconds number come from?
The component datasheets...

Tpd abs max/595 = 63ns * 16 devices/panel * 12 panels = 12096 nanoseconds
Tpd abs max/245 = 22ns * 12 panels = 264 nanoseconds

Add both, 12360 ns = 12.36 us < 20 us < 50 us

Regards

Aussie_Wombat
Posts:51
Joined:Tue May 22, 2012 12:52 pm

### Re: 12 panel display

Hi,

I have 9 panels in a 3x3 layout, and will be going onto 21 panels (3 wide x 7 down) once I sort out the Roving networks RN 42 XV bluetooth drama with appinventor..

Regards Dennis