Hello,
I have bought a few of these 8x8 common anode LED arrays a few years ago. I want to show alphabets etc. on one of them. I will only use green color LEDs. I want to use 8 output ports to specify which LEDs (rows) in each column will turn on (ports 2-9). At the same time I want to use 8 other ports to activate the cathodes for each column (ports 22-29).
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What should I do for the cathodes? Use NOT gates (since they are cathode)? I guess that is not possible because of the required fan out for 8 LEDs.
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I have some of these 2803 darlington drivers. How can I use them to provide cathode for the LED columns? Just give a high output to the input of darlington and connect the output to the cathode of the columns?
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I will later use 4017 or 74595s to scan through the columns (I will have 10 of these arrays).
I appreciate your kind help.