I'vd been through this app note before also, and come to the same conclusions on the comparitor inputs as being unused. My conclusion was it used duty cycle only current control, and that it used a VS equal to the coil voltage of the motor, thus no chopping action on 100% currents. I can't say that I subscribe to free running async duty cycle variation as a good method to do microstepping.
Phil, Still too many interests, too many projects, and not enough time!!!!!!!!
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