The MC2 Microdrive Motor Controller supports a single motor microdrive.

The 3-wire stepper motor on the microdrive responds to current flowing into one lead wire and out another, while a third conducts no current.

There are 3 pairs of active lead wires, and 2 current polarities in each case, so there are a total of 6 drive states. Sequencing through the appropriate six steps in order causes one rotation of the motor shaft. Turning off the drive current would normally allow the motor shaft to turn freely. However, friction from the motor assembly gearbox and leadscrew prevent passive rotation of the motor shaft.

The motor controller manages ramp up and down of motor drive current and sequencing through drive states to add or remove steps. The controller keeps track of the total steps taken since the last reference count was established.

The MC2 provides a motor activity blanking signal during this sequence. This can be used to disable electrode preamps, which might otherwise be swamped by motor drive current induced noise.

A fast response current and voltage protection circuit helps avoid motor damage. The same circuit permits the motor connections to be measured to confirm correct wiring and health of the motor magnet coils.

The MC2 can be powered and operated from a host computer as a USB device, using RP Metrix provided software. There is also a standalone mode, using a 5V DC supply and a standard USB mouse, to support manual operation of a microdrive motor during assembly of the microdrive or attachment of electrodes.