USB Host Shield MIDI support

[tttapa]

@sushyoshi

Hello,

I would like to know if anyone is working on making Control Surface work together with an USB Host Shield.
The idea would be getting input from an usb midi device connected to the usb host shield on an arduino or esp, and then pipe the midi data to the serial TX of the arduino.

Sorry if this has already been accomplished or done, but I cannot seem to find any information about it.

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@tttapa

The new-input branch has an implementation for USB Host MIDI for Teensy 3.6/4.1:
https://github.com/tttapa/Control-Surface/blob/new-input/src/MIDI_Interfaces/USBHostMIDI_Interface.hpp

As you can see, you just have to implement 4 functions:

• read() that reads a USB MIDI packet from the receive buffer
• write() that adds a packet to the send buffer
• sendNow() that actually sends the send buffer over the USB bus
• preferImmediateSend() that returns true if the sendNow() function should be called after each message, or false if the buffer will be sent automatically and asynchronously.

I don't intend to add support for USB Host shields myself any time soon, because then I'd have to support different shields and many different USB devices that require slightly different drivers, but as shown above, if you have a working USB host library, integrating it with Control Surface should be trivial.

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@sushyoshi

Thank you for your answer. I will try to get it working that way. The goal is to use Control Surface library to create a USB and BLE MIDI to Serial DIN MIDI Interface. Right now I am using the USB Host Shield for USB to Seial MIDI conversion and using Control Surface for BLE to MIDI conversion. However the libraries seem to conflict working together so if I can only use Control Surface for this would be great. Thanks. V

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(Transferred from #463)