If you load a main.py file onto the Pico with micropython firmware running, it will run on startup. I can tell that this is working because I observe GPIO outputs changing, etc.

However, I'm not sure where output is going in this mode (e.g. print). I've tried connecting to the USB but I just get the usual REPL. I've also tried hooking up a UART probe (specifically, the Raspberry Pi debug probe) to default UART, but I'm not getting output there either (this is the default output for printf when using the C SDK, and I can successfully see output from any C firmware that uses printf using my debug probe).

Does anyone know where this output is going and how to see it?

I'm also actually using a Pico W but I assume this wouldn't differ from the Pico.

1 Answer 1


The print goes to USB. If you use Thonny you will see the result.

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