I had a bug in my USB host control driver code that I was able to track with the BitScope.
I used the BitScope's logic inputs and digital storage oscilloscope to trigger and capture full-speed USB transactions.
I used a general purpose output of the MCF52221 to trigger the BitScope right before the transaction that led to trouble, and then captured USB D+ using the Channel A BNC.
I then used the vertical markers to perform my own clock recovery on the 12 Mbps NRZI signal. :-)
You can see below a USB control transfer that uses DATA1 PID (starting at the marker).