Mega 2560 USB midi

Is the usb connector only for programming the mega or can I use that to send/receive midi info via computer. Or will I need another device to send midi over usb?

Also, how many switch/buttons can I use with this device? 54?

Thank you!

Is the usb connector only for programming the mega or can I use that to send/receive midi info via computer. Or will I need another device to send midi over usb?

Sorry, I'm no Midi expert,

but I managed to find something,

Have you tried searching for "midi over usb arduino"?

These library allows any microcontroller with native USB capabilities (atmega32u4 based boards or ARM boards) to appear as a MIDI peripheral over USB to a connected computer.

Also, how many switch/buttons can I use with this device? 54?

Arduino Mega 2560 Rev3

With 54 digital I/O pins

There are many ways to monitor keys / buttons, if you use a button for each entry will be the least possible. But if you use an array configuration the amount will be much larger.

The Matrix Keypad how-to

I know you're getting started, but please try to put your questions on Google, this already helped me a lot in the beginning.

And, please try to ask one topic at a time, when the questions are very basic or of varied topics, few people will be interested in answering.

Good luck!