Budget logic level analyzer

[pcprogrammer]

The vendor debugging tools of course do this without any hardware as long as you have a compatible USB connection to the board.

But if you need to debug physical signals, you can use another cheap fpga board (such as tang nano etc) and connect some of the pins to its debug core.

The Raspberry PI Pico is way cheaper than any FPGA board, and as others wrote in this thread it can do reasonable high speed sampling.