I definitely read about these. They seem to cut current on/off so I couldn't figure out how I could use them to reverse the polarity of the current?
In the details, there is FWD/REV/BRAKE/COAST
Simplifying there is FWD/REV; Default = brake
There's also DIRECTION and NOT ENABLE methods.
The classic reversing switch is the DPDT relay with the corners crossed. DC say enters the common terminals and exists on the diagonal. So, yo can get FWD - OFF - REV with a single DPDT Center-Off switch.
There is burst of high current when a motor first turns on, so that burst has to be ignored. e.g. I>x for some length of time to software detect a limit.
This https://cache.freescale.com/files/microcontrollers/doc/ref_manual/DRM160.pdf gives you an idea of how it's done in a car. Note,they detect stall, not a slam.