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Topic: building LED wall using 60 8*8 LED matrices (Read 4120 times) previous topic - next topic

CrossRoads

Buffer SCk, SS, MOSI out to each string. Use 6 chip selects if there is enough IO pins. Otherwise,  let MAX7219s be the data in to data out buffer, and just have the SS & SCK buffered.
3 to 8 decoders are generally 1 of 8 outputs low, that doesn't help on data; would help on chip select.
http://www.digikey.com/product-detail/en/CD74AC138E/296-4225-5-ND/375864
Good drive current to get across lots of PCB traces and wiring, vs wimpier HC parts:
http://www.digikey.com/product-detail/en/SN74HC138N/296-1575-5-ND/277221
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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