:cold_sweat: SO I HAVE A REALLY NICE 8x8 Matrix! But it is RGB, and the example on here (arduino site) is single color Red LED, so how would I use the other COLORS???Is it just a code/sketch software thing, or hardware and software both as I believe it would be?? Also in the breadboard diagram there aren't any resistors, doesn't the matrix need resistors????? I dont want to hurt my Nano or the matrix, but my nano for sure!!! It is a common anode display 8x8 RGB Matrix from hobbypartz.com. PLZ HELP I WANT TO USE THE AWESOME MATRIX


Oh, you tease!
You're going to leave us guessing, aren't you?

Please, pick up your keyboard, turn it over and give it a really good shake - something is causing your shift and question mark keys to stick.

Does the matrix have 24 anode pins for the colors, and 8 cathode pins?

If so, get yourself 3 MAX7219, and 24 low voltage schottky diodes.
Each MAX7219’s segment outputs will connect to a set of anodes.
Each MAX7219 will connect to the cathodes using the the diodes. Connect the anodes to the digit pins, connect the cathodes to the cathodes of the diodes from the MAX7219s.
Write multiplexing code to let each MAX7219 share control of the common cathode using SHUTDOWN mode.

“Shutdown Mode
When the MAX7219 is in shutdown mode, the scan oscillator is halted, all segment current sources are pulled to ground, and all digit drivers are pulled to V+, thereby blanking the display. The MAX7221 is identical, except the drivers are high-impedance. Data in the digit and control registers remains unaltered. Shutdown can be used to save power or as an alarm to flash the display by successively entering and leaving shutdown mode. For minimum supply current in shutdown mode, logic inputs should be at ground or V+ (CMOS-logic levels).
Typically, it takes less than 250?s for the MAX7219/ MAX7221 to leave shutdown mode. The display driver can be programmed while in shutdown mode, and shutdown mode can be overridden by the display-test function.”

Common anode RGB matrix could be similarly driven, with the diodes on the segment pins instead, and each MAX7219 controlling the discrete cathode pins.

MAX7219-MAX7221.pdf (451 KB)