The Usb Sniffer Lite for RP2040 is a simple USB sniffer based on a Raspberry Pi RP2040 that supports Low Speed and Full Speed modes. It presents itself as a virtual COM-port and requires no additional software for compatibility with all operating systems. While it lacks packet decoding capabilities, an online USB Descriptor and Request Parser can assist with standard descriptors and requests. Hardware connections for the USB D+ and D- signals to the MCU pins are provided, with a pictorial example of a quick, DIY cable. The sniffer includes a trigger mechanism for marking points of interest. A dedicated board with an integrated FE8.1 USB HUB simplifies setup. Various settings and commands are available for customization and control.
https://github.com/ataradov/usb-sniffer-lite