Beginner Help: Printing Midi Messages on SH1106 Display

[tilllt]

Hey there,

quick intro:
my longterm dream would be to connect my Polyend Tracker and my Boss BR-800 (and possibly other Devices like my Pocket Operators) wirelessly, so i can run them in sync, without "computers" involved.

But i am taking it slowly: I started off with a Arduino Nano 33 BLE, but i learned that BLE is not supported with the Nano 33 (yet) by Control Surface, so now i have set up a Lilygo ESP32-S2 with a generic Aliexpress SH1106 SPI Display, i cant get the U8G2 library to work but both the Pololu SH1106 and the Adafruit SH1106 Libraries work.

So as a first step, i would like to use the ESP32 in USB Host Mode, connect the BR-800 and display its Midi Messages (MTC would be lovely) on the SH1106 display - since the USB port is occupied by the BR-800 i cannot use serial monitor. I have some ESP32-C3 with dual USB Ports on the way, but i dont know when they will arrive and if they will cause other problems that i cannot foresee now.

I started browsing the docs the examples, but when it comes to adding a currently unsupported Display (as far as i can see only SSD1306 is supported right now), and sending the "mididbg" output to anything else but the serial port, i am lost.

Would appreciate any pointers to advance with this!

[tttapa]

i would like to use the ESP32 in USB Host Mode

Unfortunately, this is not currently supported. The ESP32-S2 uses TinyUSB for its USB stack, and TinyUSB only supports MIDI in Device mode, not Host mode. Implementing MIDI Host mode requires implementing a custom device driver, using the low-level TinyUSB and ESP-IDF APIs, and is not a trivial task, because you need to have good knowledge of the entire USB spec. Device mode is much simpler.
To further complicate matters, it seems that the Boss BR-800 can act as both a MIDI device and an audio interface. If you're lucky, those are two Interfaces on a single USB device, if you're unlucky, they're two separate devices behind a USB Hub. Your USB drivers need to be able to deal with such a topology.

See MIDI over USB for a table of supported boards.

The only Arduino-compatible boards with good USB MIDI Host support that I'm aware of are the Teensy 3.6 and 4.1.

display its Midi Messages (MTC would be lovely) on the SH1106 display

That's certainly doable. See MIDI-Monitor-OLED.ino. Switching from Adafruit_SSD1306 to Adafruit_SH1106 should be a trivial change, it's unrelated to the Control Surface library.

since the USB port is occupied by the BR-800 i cannot use serial monitor.

In that case, I'd highly recommend getting one of those cheap USB-to-UART converters (e.g. one based on the FTDI-232RL chip). Connect it to e.g. Serial1 and use that for the serial monitor.
Alternatively, get an ESP32 dev board with such a chip built-in (e.g. the ESP32-S3 devkit by Espressif).

I have some ESP32-C3 with dual USB Ports on the way, but i dont know when they will arrive and if they will cause other problems that i cannot foresee now.

Are you sure you've ordered the ESP32-C3? It does not have USB support (only for Serial and JTAG, but not anything else like MIDI).

I started browsing the docs the examples, but when it comes to adding a currently unsupported Display (as far as i can see only SSD1306 is supported right now), and sending the "mididbg" output to anything else but the serial port, i am lost.

There is no need to add any unsupported displays. The display operates independently from the Control Surface library. You just use the Adafruit library, directly in your sketch.

[tilllt]

Thanks for taking the time, I appreciate it. Seems really difficult to find the supported board for this specific purpose. I like the teensy boards but they are quite expensive in comparison to an average ESP32 dev board...

These are the dual USB ESP32 boards I mentioned:

https://de.aliexpress.com/item/1005004617322170.html

So, to clarify, since I saw this page has a USB Midi Host example for the esp32-s2. But it would not be possible to combine these and make them work with the control surface library? But generally speaking the hardware is capable of acting as a USB midi Host?

https://github.com/touchgadget/esp32-usb-host-demos

[tttapa]

Sure, if the code in the esp32-usb-host-demos repository works for your BR-800, it should be trivial to integrate with Control Surface. You can use the Custom-USB-MIDI-Backend.ino example to get started.

[tilllt]

I found an even more promising project for the ESP32-S3 (probably works with the S2) with a complete USB Midi Host to BLE Sketch in the examples folder, using freeRTOS threading and all:

https://github.com/aselectroworks/AtomS3_USB-BLE_MIDI_Bridge