The Arduino then controls the state of the LED using the active high enable line from the column multiplexer chip. [Alex] wanted more than just a static image to show off on his new display, so he ...

Only one LED is lit up at any time. [Kathy] used a pair of 74LS138 3-to-8 line decoders to scan the matrix. The active low outputs on the ‘138 would be perfect for a common cathode matrix.