Teensy: Use Serial Monitor when USB Type: "MIDI"

Is it possible to use Serial Monitor with USB Type: “MIDI” with PlatformIO CLI (IDE respectively)? The problem is that in the standard Arduino IDE, when you choose USB Type: “MIDI” there are no more COM1…2 etc, it’s just MIDI, but the Serial Monitor does work correctly. In PlatformIO I have only COM1 available which seems irrelevant port for MIDI configuration, thus no messages are displayed in the console.

BTW, I wasn’t able to find any documentation about serialports command, this page is broken for some reason: Redirecting...


It seems for me that I heard this question maybe 1 year ago. Teensyduino has virtual implementation of Serial Port in MIDI mode. I’m not sure that it will from the box :frowning: Need to wait maybe someone will implement it.

Thanks, I fixed this link

I was left with the impression that everything that is possible with Arduino/Teensyduino/etc. is theoretically possible with PlatformIO. Are you saying that you depend on someone else’s implementation? Sorry didn’t understand your answer. No worries though, I can workaround it by toggling the “native” Serial Monitor if someone’s interested and faced the same problem.

Thanks once again.

You are right, PlatformIO is a crazy powerful ecosystem. You can extend it in any ways. If something doesn’t work here, it means that it’s not implemented (but not that it is impossible) :slight_smile:

Arduino IDE doesn’t support this “MIDI trick”. This a Teensyduino hack. Each time when new Arduino IDE is out, Paul from Teensy apply own Java patches. See Import Teensyduino patches · PaulStoffregen/Arduino-1.6.9-Teensyduino@7881f4e · GitHub



I’ll pray for this to be implemented :relieved: there’s nothing left I could possibly want from PlatformIO.


are there some news about that?
I’m facing exactly the same problem and I need the Serial Monitor to “debug” by stuff … I want to print some values into the serial monitor for some MIDI events, therefore I can’t switch the build flags :frowning:


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Hi Tino,

please did you find any solution? I’ve been reading this and other forums, but not able to find any solution :smiley:

Thnaks, Michal

Can you please post a full example of you setup serial messages via MIDI in the Arduino IDE? Screenshot of Arduino IDE configuration, board type and full code please.

After looking at Make Serial Monitor work with USB Type: "MIDI" · Issue #6 · platformio/platform-teensy · GitHub one might be able to use the teensy_serialmon program in VSCode directly (very easy) or integrate the PlatformIO core with it, either by re-implementing the logic found in that serial monitor in Python or by calling into that executable. But for that I need to have a reproducable setup that works in the Arduino IDE (and the right board – I only have a Teensy 4.0 now)