Steppers
The stepper driver subsystem consists of two device driver APIs:
Stepper API
The stepper driver API provides a common interface for stepper drivers.
Configure micro-stepping resolution using
stepper_set_micro_step_res()andstepper_get_micro_step_res().Enable the stepper driver using
stepper_enable().Disable the stepper driver using
stepper_disable().Register an event callback using
stepper_set_event_cb().
Stepper Motion Controller API
The stepper motion controller API provides a common interface for stepper motion controllers.
Configure reference position in microsteps using
stepper_ctrl_set_reference_position()andstepper_ctrl_get_actual_position().Set step interval in nanoseconds between steps using
stepper_ctrl_set_microstep_interval()Move by +/- micro-steps also known as relative movement using
stepper_ctrl_move_by().Move to a specific position also known as absolute movement using
stepper_ctrl_move_to().Run continuously with a constant step interval in a specific direction until a stop is detected using
stepper_ctrl_run().Stop the stepper using
stepper_ctrl_stop().Check if the stepper is moving using
stepper_ctrl_is_moving().Register an event callback using
stepper_ctrl_set_event_cb().
Device Tree
In the context of stepper motion controllers, devicetree provides the initial hardware configuration for stepper drivers on a per device level. Each device must specify a device tree binding in Zephyr, and ideally, a set of hardware configuration options for things such as current settings, ramp parameters and furthermore. These can then be used in a boards devicetree to configure a stepper driver to its initial state.
Driver Composition Scenarios
Below are two typical scenarios:
Stepper Motion Controller API Test Suite
The stepper motion controller API test suite provides a set of tests that can be used to verify the functionality of stepper motion controllers.
# From the root of the zephyr repository
west build -b <board> --extra-dtc-overlay <path/to/board.overlay> tests/drivers/stepper/stepper_ctrl
west flash
Sample Output
Below is a snippet of the test output for the h-bridge-stepper-ctrl.
===================================================================
TESTSUITE stepper succeeded
------ TESTSUITE SUMMARY START ------
SUITE PASS - 100.00% [stepper_ctrl]: pass = 10, fail = 0, skip = 0, total = 10 duration = 6.869 seconds
- PASS - [stepper_ctrl.test_actual_position] duration = 0.001 seconds
- PASS - [stepper_ctrl.test_move_by_negative_step_count] duration = 2.207 seconds
- PASS - [stepper_ctrl.test_move_by_positive_step_count] duration = 2.202 seconds
- PASS - [stepper_ctrl.test_move_to_negative_step_count] duration = 1.106 seconds
- PASS - [stepper_ctrl.test_move_to_positive_step_count] duration = 1.102 seconds
- PASS - [stepper_ctrl.test_move_zero_steps] duration = 0.006 seconds
- PASS - [stepper_ctrl.test_run_negative_direction] duration = 0.115 seconds
- PASS - [stepper_ctrl.test_run_positive_direction] duration = 0.124 seconds
- PASS - [stepper_ctrl.test_set_micro_step_interval_invalid_zero] duration = 0.002 seconds
- PASS - [stepper_ctrl.test_stop] duration = 0.004 seconds
------ TESTSUITE SUMMARY END ------
===================================================================
PROJECT EXECUTION SUCCESSFUL
API Reference
A common set of functions which should be implemented by all stepper drivers.
A common set of functions which should be implemented by all stepper motion controllers.