I am a new user of the NXP microcontrollers (LPC55 series). And I'm just taking my first steps with MCUExpesso and maybe FreeMASTER.
Because I use a USB interface, among others HID Class, Vendor Class and Audio Class. I thought about creating a USB transmission monitor with the option of viewing the transmission for a given class or endpoint.
I'm using the monitor from the PC side but sometimes something goes wrong from the microcontroller side.
And such a monitor would be useful.
I'm just getting to know FreeMASTER so I don't know if this idea is possible to implement.
I think FreeMASTER could help to display performance data about the USB transmission (data throughput, error counts etc) if you would be collecting them in your application. FreeMASTER may communicate directly over USB CDC class, but in your case I think it would be better to use a different interface (e.g. debugging serial line or direct JTAG access) not to influence the USB communication.
Please try to explain your plan in more details - what USB communication parameters would you like to monitor etc. and we can discuss further.