Abstract: A system and method for auto-addressing devices on a multiplexing bus in which a plurality of devices are arranged in series, with each having a bus in and bus out. During an initial evaluation, and beginning with a low bus in, each device inverts the incoming signal so that a device with a low bus in has a high bus out. During a second evaluation, the high or low state of the bus in is inverted only if the bus out in the first evaluation was high. Similarly, during subsequent evaluations, the high or low state of the bus in is inverted only if the bus out state of all previous evaluations was high. Ultimately, only one device will have a high bus out, with all bus out states from previous evaluations also having been high, at which point all addresses are fully decoded.

Abstract: A stall detection circuit and method for a stepper motor. The circuit has an H-bridge configuration with an additional circuit pathway to ground being connected at a point between two center windings. During the transition between step sequences, the circuit employs a monitoring phase in which the previously active low side driver is turned off such that current passes through only the first winding and then is diverted to ground via the additional pathway. While the phase voltage is thus momentarily extinguished, the second coil is used to monitor the motor's back EMF, from which it can be determined whether the rotor is in a normal running mode, a stall, or a reverse condition.