Stepper motors move in steps which is usually 1.8°, that is 200 steps per revolution. This can be a problem when we need small movements.
One option would be to use some kind of transmission but there is also another way – micro-stepping. Micro-stepping means that we can have more than 200 steps per revolution and in turn have smaller movements. This option is already integrated into most ICs and can be configured by simply moving a jumper like on PoStep25-32.
When driving stepper motors with full steps the output of the stepper motor driver looks like a square signal and produces rough movements. The bigger the micro-stepping the more the output signal looks like a sine wave and the stepper motor moves more smoothly. But there is a downside to this. With increasing micro-stepping value the torque drops a quite lot and if the value is too great it could happen that the motor can’t produce enough torque to even turn.
Usually, 1/4, 1/8, or even 1/16 can produce satisfactory smooth movements while still producing enough torque.
So what do these micro-step values even mean?
Micro-stepping tells us how many micro-steps should a stepper make to produce one full step. The 1/1 value tells us that the stepper must make one micro-step to produce one full step (so there is no micro-stepping).
Value of 1/2 is called a half step and tells us that the stepper motor must make 2 micro-steps for one full step. This means that the stepper motor should make 400 steps for one full revolution. A value of 1/8 will tell us that the motor should make 8 micro-steps for one full step and 1600 steps for one full revolution. The same principle applies to all of the micro-stepping values.