Yep, that's it. Note there are some additional optional "V3" features, namely: Extra buttons (Track Group A/B/C/D, Trigger Layer A/B/C, Stepview 16-32) Extra LEDs (As for the switches above, plus Play/Pause/Stop) You'll notice there aren't enough DOUT pins for those extra LEDs, so you'll either need another DOUTX4 module (doesn't need to be fully stuffed) or your own solution (etch a PCB, protoboard etc.). You'll need to slightly modify the asm code (easy, just assign pins) if you want any of these. There's also a 64 button LED/button matrix which is "not recommended for beginners", but will require more shift registers.