A Rigol DSO804 to be specific. Now I can finally diagnose some of the issues that have been plaguing my Motor Controller.
I verified that the 12 volt rail was not coupling with the 3.3v signal line, but the DRV8825 driver soldered to the board is apparently just a cheap knockoff. The nasty screeching sound caused by~ 12kHz pulsing is partially due to a chip malfunction, although my lack of consideration for EMI didn’t make diagnosing the issue easier.
The third PCB revision is underway having now ironed out most of the most pressing and obvious issues – although the tarrifs are going to make getting the right components a bit harder.