Can Scout run as a USB Host so I can create a MIDI HID driver?

caseya 2015-01-31 05:34:06 UTC #1

I have found a couple arduino projects that allow MIDI communication through the USB interface, but have mostly heard that people at getting USB shields for it. The basics count has a USB interface. Can I program that to transmit MIDI packets to a Novation Launchpad MIDI controller of mine? Thanks.

Arduino project for MIDI HID though USB

Matthijs 2015-01-31 10:09:41 UTC #2

The project you linked uses the 8u2 chip on an Arduino Uno, which does the USB -> Serial translation and programs it to register itself as an USB midi device, which can then be controlled from the main Atmega328 MCU through the serial connection.

This approach could also work with the Pinoccio - we use a 16u2 (IIRC, might be 32u2) for the USB -> serial which is similar. This is not a trivial project, though. It will probably requiring their source for the 16u2 on the pinoccio, possibly updating it for our pinout. Also, replacing the firmware on the 16u2 has the potential for bricking it, up to the point where you'll need an ISP programmer to fix it.

caseya 2015-02-01 01:00:45 UTC #3

Ok thanks for the reply. You talked about how there is potential for bricking the device because I'll programming the firmware on it. I'm new to the Arduino scene so I assumed that when I use the Arduino IDE to program, that I was programming the firmware. Is this not the case? Is there not always a risk of bricking when we are programming these puppies? I've read briefly about a scripting thing. I imagine that it is an interpreted thing build as another level on top of the low-level firmware. It's a little confusing how things work under the covers of these scouts. Any help here? thanks

Matthijs 2015-02-03 09:14:44 UTC #4

Normally, when uploading code, you program the firmware/software of the atmega256rfr2 chip (the big one). However, there's also a atmega16u2 chip on the board (the smaller one), which handles USB -> serial conversion. Normally, you do not modify its firmware, it just does its thing.

If you replace the 16u2 firmware using "DFU" mode (which I think the scouts support), I think there is a chance that you replace it with a non-working firmware, which also stops doing DFU, preventing you from uploading another firmware to the 16u2. I'm not entirely sure how DFU mode is implemented, it might be safer than I think (e.g. just like uploading a normal sketch to the scout shouldn't be able to brick things, since you never replace the "bootloader" - a piece of code that takes care of uploading new sketches, which cannot overwrite itself).

Does that help?

caseya 2015-02-03 21:02:40 UTC #5

Ok this makes a lot of sense now yes. Its good to know there are 2 components involved here. Thanks.