If I understood correctly, the TMC2100 is actually a hybrid between 16 and 256µSteps/Step. When even 8-Bit electronics give out 1 step as set with the M1,M2,M3 Jumpers to 1/16th microstepping the driver internally gives out 16 µSteps at 1/256th resolution at once.
This is the said mix between 1/16th and 1/256th, since the controller and firmware assumes that the driver can only do 1/16th microstepping. In reality however the motor gets 16 step pulses in 1/256th microstepping.
So theoretically every electronics that can handle 1/16th µstepping fast enough (all that I know of) can do the pseudo-1/256th as well.
This is the said mix between 1/16th and 1/256th, since the controller and firmware assumes that the driver can only do 1/16th microstepping. In reality however the motor gets 16 step pulses in 1/256th microstepping.
So theoretically every electronics that can handle 1/16th µstepping fast enough (all that I know of) can do the pseudo-1/256th as well.