Can I use a Arduino Mega 2560 as a multiplexer?

Question

I have a 4*4 push button pad with RGB LEDs (brought from sparkfun) connected to a Arduino Mega 2560. At first I wanna use the button pad as a MIDI controller, but now I discovered that Mega 2560 cannot use as a MIDI devices. I have a Teensy 3.2 with the audio shield here, is it possible to let two MCU communicate together?

Answer 1

Can I use a Arduino Mega 2560 as a multiplexer?

Depends on what you want to multiplex, but in general yes. Do you even know what a multiplexer is?

I discovered that Mega 2560 cannot use as a MIDI devices.

That's not true.

I have a Teensy 3.2 with the audio shield here, is it possible to let two MCU communicate together?

Of course. There are countless ways.

I'd recommend that you learn a few basics first. I wouldn't think that someone who asks questions like that is fit to implement any project beyond blinking an LED perhaps.

Why don't you start with a few tutorials so you get a feeling for how to do things, and what is possible.