The goal here is to have a USB peripheral, so that this little device can plug in on USB and identify to the host system as an audio source (likely without even

The goal here is to have a USB peripheral, so that this little device can plug in on USB and identify to the host system as an audio source (likely without even needing to install a driver, since audio sources & sinks are part of the USB spec). The RP2040 has built-in support for being a USB peripheral in its hardware, plus good support in the SDK for it. By contrast, the ESP8266 is not designed to be a USB peripheral. Usually it's used with a USB-to-serial converter when you need to connect it to a host computer. This allows, well, serial transfers. It can't appear to a host computer as an audio source. There might be ways to do it, such as bit banged USB or custom drivers on the host computer that treat a serial port as an audio source, but by using a microcontroller with built in USB support, a lot of headaches can be avoided. If you are particularly "into" the Espressif ecosystem, the ESP32-S2 and ESP32-S3 microcontrollers both have native USB support which would make them potential candidates for a similar project.