How to use Step Stick Steppers in MPF

Related Config File Sections

MPF can drive steppers on a StepStick (or DRV8825) connected via a digital output. Depending on the jitter of the output the speed might be limited to a few steps per second (like 50-200).

Configuring your stepper

A step stick stepper needs two or three outputs which define the hardware number: direction_output:step_output or direction_output:step_output:enable_output. In case you omit enable_output make sure it is pulled high permanently. In addition, you need a homing_switch so MPF can find the 0 position of your stepper at startup.

This is an example:


    stepper_controllers: step_stick

    number: 1
    type: driver
    number: 2
    type: driver
    number: 3
    type: driver

    number: 1

    number: c_direction:c_step:c_enable   # enable is optional
    homing_mode: switch
    homing_switch: s_home
      10: test_00
      20: test_01
      50: test_10
    platform_settings:  # optional speed settings
      low_time: 20ms
      high_time: 20ms

You might want to change the speed in the platform_settings section. 1000 / (low_time + high_time) will be your number of steps per second.

Connecting your stepper driver

Connect the DIR pin to your direction_output, STP to your step_output and``GND`` to your ground. If use an enable_output connect it to EN, SLP and RST (not all driver have all of them). Otherwise, pull them to VDD or the driver will not work. In addition, you need to pull M0, M1 and M2 to VDD or GND to configure the step resolution. Your stepper will connect to 1A, 1B, 2A and 2B. Connect power to VMOT (do not forget to also connect ground of your stepper power supply; see Voltages and Power). See the datasheet for details about your driver.