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Topic: Bicolor 8x8 LED matrix with MAX7219 - tutorial clarifications (Read 2724 times) previous topic - next topic


Dear All,

I would like to follow this tutorial http://playground.arduino.cc/Main/MultiplexMAX72xx to drive my bicolor matrix (http://shop.boxtec.ch/pub/sure/LE-MM103_1.pdf) with two MAX7219.

Mine it is a common anode matrix, while the tutorial shows the schematics for a common cathode matrix.. does anyone can help me to find the correct schematic? I have tried to search but cannot find anything..

The schematic reported is a bit small.. I think i recognize a couple of resistance 26k R1 and R2.. and a couple capacitor but I don't see their value, any advice with that?

Thank you,


This may "throw some light" on this topic  8)



Thank you Pedro for your reply..
Actually the topic you suggested me contributed to increase my doubt..  :smiley-roll-sweat:
Plus it seems there is no library for common-anode led matrix.. hum...


The MAX7219 & MAX7221 LED driver chips are designed for common cathode displays and not really suitable for common anode.
From the first paragraph in the datasheet...
The MAX7219/MAX7221 are compact, serial input/out-
put common-cathode display drivers that interface
microprocessors (µPs) to 7-segment numeric LED dis-
plays of up to 8 digits, bar-graph displays, or 64 indi-
vidual LEDs.

It would be a lot simpler to buy a common cathode LED module.
Don't PM me for help as I will ignore it.

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