Run an 8x8 LED Matrix using 3 pins!

(Expand for Errata) Previously, we looked at the 8x8 LED Matrix. We noted that, since it needs 16 pins to power, we'll have to sacrifice quite a lot of pins on the microcontroller. I left this as an open question at the end of that episode, which you can watch here → https://www.youtube.com/watch?v=G4lIo-MRSiY

In this video, we try to look for ways to cut down on the number of pins, through use of our trusty 74HC595N shift register! We first looked at this nifty little component, which helps store one byte of data, in this video → https://www.youtube.com/watch?v=MRy47jCn3zA

By combining two shift registers with the LED Matrix, we can eliminate almost all of the pins used to drive the matrix. What's even better is, the first shift register can drive the second, reducing our pin count down to just 3.

Want to see the code? Downloads are here: https://bitbucket.org/nerdfirst/arduino-8x8-with-shift-register

To download, click "Download" on the left sidebar, and select "Download Repository".

= ERRATA =
Please note the mistake at 9:10 - In the diagram, the shift and store pins have been reversed. The store pin should be above the shift pin. Thank you very much to Joshua Thyer for pointing out the error!

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