Power

• VDD - This is the logic voltage input. To power the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V micro like Arduino, use 5V. It can be powered between from 3.3V to 5V.
• + (terminal block) - This is the motor voltage input. Supply 1.8-10VDC for your motor.
• GND / - (terminal block) - common ground for power and logic.

Current Potentiometer

On the right side of the board is the current potentiometer. This potentiometer limits the current output to the motor. When the potentiometer is all the way to the right, you can get up to about 1.3A max.

Terminal Block Bipolar Stepper Motor Connections

• 1A and 2A - The first set of motor control outputs connected to DMOS bridge 1.
• 1B and 2B - The second set of motor control outputs connected to DMOS bridge 2.

Stepper Control Pins

• DIR - This is the direction control pin. You can set this pin high or low to set the spin orientation. Pulling it high turns the motor clockwise. Pulling it low turns it counterclockwise.
• STEP - This is the microstep control pin. Toggle this pin to take one step or microstep at a time. By default, the driver is set to 1/16 microstep mode.

LEDs

• Green LED - The green LED is tied to the DIR pin. It is labeled F on the board silk. It is lit when the motor is being driven counterclockwise when the DIR pin is low.
• Red LED - The red LED is tied to the DIR pin. It is labeled B on the board silk. It is lit when the motor is being driven clockwise when the DIR pin is high.
• Yellow LED - The yellow LED is tied to the STEP pin. It is labeled S on the board silk. It is lit when the motor driver is being moved.

STSTEP220 Control Pins

• EN - This is the enable pin. Pull this pin high to disable the output to the motors.
• RST - This is the reset pin. Pull this pin low to reset the STSTEP220. This pin is also used when setting the microstep mode.

Microstep Selection Pins

There are two pins (MS1, MS2) that can be pulled high or low in combination with the DIR and STEP pins to change the default 1/16 microstep mode where all four pins are open/high. The table below shows the pin combinations to change to the different modes. For example, if you wanted to use 1/4 microstep mode, you would tie STEP and MS1 to ground (closed/low) and leave DIR and MS2 as-is (open/high).

You'll need to reset the breakout with the RST pin to enable a new mode since it is latched at power-up.

This table is also available on page 9 of the STSPIN220 datasheet. If you don't want to have to worry about referencing this table for your project, you can use the Arduino or CircuitPython library to set the step or microstep mode instead or doing it manually.