tinyusb VS display-switch

Implementing the required USB host interface is another hurdle, but tinyusb seems to have sorted most of that out, except that UAC2 is implemented as a device while you need a host.

Have a look at TinyUSB. It supports the STM32WB and demo programs for the Nucleo-WB55RG. It even offers an example for dual CDC ports, so very close to what you're looking for.

Second: Distrust, misunderstanding, and out of date opinions of C++ in embedded spaces. I often see "compatibilty" thrown around as a goal for using C and not C++, but for most modern embedded systems, C++ compilers exist and are (usually) well tuned. Arm is a shining example here*. C++ is more optimizable than C as the intent can be clearer to the compiler. C++ constexpr and templates are a godsend for embedded systems, and I used both heavily in my recent arduino and pico testing. I combined both of them for a really cool experimental USB interface descriptor builder that runs at compile time and avoids the need to count byte sizes, but I gave up on it when the maintainer said C only, despite the fact that C can't do that. I was similarly disappointed when the pico "C++" was C only, as there was no backwards compatibility necessary.

I looked at this but the fork seems to have had a lot of problems from looking at the PR: https://github.com/hathach/tinyusb/pull/1219

I think a better solution might be to use a USB flash drive in the usbc port. Unfortunately micropython and circuitpython don't support this (yet), so you'd have to use c++ https://github.com/hathach/tinyusb

It's possible to make the s3 be a mass storage device via TinyUSB. https://github.com/hathach/tinyusb/tree/master/examples/device/cdc_msc_freertos

I’ve been using display-switch[0] for this for a while now. No problems whatsoever. Works on windows/mac/linux.

[0] https://github.com/haimgel/display-switch

Now it just need to be combined with something like https://github.com/haimgel/display-switch to do a DDC/CI monitor input switch as the USB activity moves around.

With a device like this you'd be missing the on_usb_connect event, but presumably you could do something (a special HID device button, an extra device id appearing, who knows) to make it work.

The best option I've found is to hook both computers up to a USB-only KVM, and plug them in via separate video cables to the monitor. Then set up the computers to tell the monitor to change inputs (via DDC commands, which most but not all monitors support) when you change devices on the KVM

There's software to help do this automatically (https://github.com/haimgel/display-switch)

Cynical footnote: PC users can continue to enjoy https://github.com/haimgel/display-switch while Mac users need to buy a 300 USD device. That's the Mac experience for you :D

There's a workaround in https://github.com/haimgel/display-switch now for M1 Macs. In general, you made your bed by buying a Mac, sleep in it.

Oops I missed that https://github.com/haimgel/display-switch

Then we will run https://github.com/haimgel/display-switch to have the monitors switch inputs when you use the USB switch.