Just digging through the source code for version 7243 and stumbled apon this curiosity.
// Set the number of brushes in the motor, which determines the
// number of commutations per revolution for sensor-less speed
// This command has been handled.
Now the comments state that the command was handled although it is not. Anyone have any more insight into this?
Doesn’t the response return a status that the brush number has been set and nothing else? Since I am not a programmer, this seems flawed in that all of our motors have two brushes but the number of commutations per revolution varies from motor to motor. Some only have three commutator segments, but others have mush more. I wonder what the other part of the code uses to make the calculation.
Use a scope to look at the motor’s voltage and current under various operating conditions and see if there’s a commutator transition signature of sufficient S/N that you could detect it reliably with some custom hardware.
Or better yet, wait till TI adds that functionality to the Jag, or some third party markets a chip to do it.