I was just checking out the AS1130 and I was wondering how you are able to drive a 12x11 array of LEDs using only 12 wires? Could anyone explain this to me?


It works by what they wrongly call "Cross plexing", see Figure 24 in the datasheet. An excerpt of this figure is shown here, which demonstrates 3 pins driving 6 LEDs.

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What it should really be called is "Charlieplexing".

With Charlieplexing \$n\$ pins can drive \$n^2-n\$ LEDs.

So 12 pins can drive \$(12*12)-12 = 132\$ LEDs.

Wikipedia has a page all about it:


  • \$\begingroup\$ That is exactly what I was looking for. I kept searching for cross plexing and couldn't find anything. Thanks! \$\endgroup\$ – Tarmon Oct 7 '11 at 20:21

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