All TI's seem to be voltage set current control. either by resistor divider or DAC microstepping is a percentage of this value DRV8824 Motor Voltage: 8-45V Logic: internal 3.3v linear regulator, also used as Vref Typical 5 ma Sleep 10 uA Step and Direction control, number of microsteps are by pin selection Current set by external voltage 1/32 microstepping with internal table Allegro A3992 Motor voltage 15 - 50 Typical 8mA Sleep 20uA No step and direction nor indexer, motor control by a 6 bit DAC to set current in each winding Current level set by resistor or a voltage reference SPI interface with two 16 bit words Trinamic TMC236 Motor Voltage 7 - 35V Typical 6mA Sleep 28uA 12 bit SPI contains phase a and b percentage for micro stepping, direction, decay mode exchanges status 12 bit word which has faults No step indexer 4 bit current control for 1/16 microstepping voltage input for peak current control