In reply to ericew:
So if the only protocol on your serial bus is a valid bit or not (i.e. no framing bits), the only thing your monitor can send out through the analysis port is a single bit transaction. Then your scoreboard will have to re-assemble the bits and compare the data. You’ll probably need some sort of timeout that predicts how long after the APB master sends a command that the last serial bit should have been sent.