Firmware Reset without Re-enumerating USB serial?

[peterpolidoro]

I would like to be able to perform a firmware reset of a RP2040 while leaving the USB serial connected to an application on my host machine.

I have tried using the restart/reboot functions and using a watchdog, but they all seem to power cycle the RP2040 causing my host machine to reassign a new com port while the host application is using the previous com port.

Is it possible to perform a less drastic reset and reboot the RP2040 while the USB remains connected to the host application? Thanks!

[earlephilhower]

No. The USB port is part of the RP2040 chip and completely controlled by it. A reset of the chip is going to reset the USB interface since the state is in the core.

On things like the old Arduino Uno or some ESP boards there is a separate chip which is a dumb USB<->UART that never resets and can run even if the CPU itself is dead/resetting.

Under Linux you might look into udev rules to name the specific chip ID to a specific TTY devnode.