How the DC Motor rotation is controlled without having any current sensing circuitry?

[morisettypk]

Hi everybody, I would like to know how the DC Motor rotation is controlled without having any current sensing circuitry. Whether the rotation can be perfectly controlled when the motor is on/off. That means can it be controlled by software. The motor should not rotate even if the power to motor is Off, due to EMF or other reasons. And SPI protocol is used to transfer commands from microcontroller ot driver IC. What type of commands and how they are transmitted and how the error conditions are taken care in SPI communication.