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[Reply #15 on:]

I cant find any info about crossplexing, or how it is different than mulitplexing, or charlieplexing.

Mike,
I havnt made up a schematic for my charlieplexing, but I may be able to explain it with text.

Each LED spire is made up of 4 RGB LEDs, they could be common anode or cathode), Each LED has 4 leads, 3 color, 1 common. The leads are played out into a "+" shape, and each LED rotated 90 degrees as it goes from bottom to top, and 4 wired connect the 4 leads on the 4 LEDs. Each of the 4 leads connect to a common, and each of the 3 colors. You connect to one common lead, and any of the other leads to illuminate an individual LED. When you change the common connection, it changes which LED in the spire gets lit, when you change the color connection, it changeds with of the R, G or B LEDs that it lights.

[Reply #16 on:]

Digikey has a nice Presentation on how cross/charlieplexing works and what the differences are:
http://dkc1.digikey.com/us/en/tod/austriamicrosystems/as1130-led-driver_noaudio/as1130-led-driver_noaudio.html

The main difference that I see from the datasheet is that the crossplexed drivers can measure the voltage on each LED (as they also have open/short detection)
So a LED failor or a wrong voltage on an LED wont scrapp your matrix.

[Reply #17 on:]

Thats kinda crazy. You cant really individually control a single LED, you always lite 2 or more LEDs at a time.

I think the open/short detection is a feature found on other LED drivers too, and not specific to crossplexing, but rather specific to using constant current LED drivers.

I guess there is some benefit, in that its lighting multiple LEDS at a time, but it also seems limited, in that you lose some control of what LEDs are lit, in that you cant light one LED without lighting another one too.