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Topic: Bicolor 8x8 LED matrix with MAX7219 - tutorial clarifications (Read 2265 times) previous topic - next topic

d82k

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,
dk


Pedro147

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

http://arduino.cc/forum/index.php?topic=117102.0
http://www.pedroduino.com

d82k

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...

Riva

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...
Quote
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.
I might seem like an idiot but remember it takes one to know one.
Forum user generally fall into three categories (the good, the bad & the a**hole) what category do you fit in?

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