Module stepper 

Coil sequencing for four-wire stepper motors.

A stepper turns by energizing its coils in a repeating pattern; stepping through the pattern in one direction or the other advances or reverses the shaft. This module holds the three standard drive patterns and a sequencer that walks them, so a caller toggles the four coil lines (directly, or through a darlington array like the ULN2003) without hand-maintaining the sequence. It also models the step-and-direction interface of driver chips such as the A4988 and DRV8825, which take a step pulse and a direction level and track position as a signed count.

Coil patterns are four bits, the most significant being the first coil (IN1 on a ULN2003 board) down to the least significant (IN4).

Structs

FourWire

A four-wire stepper driven coil by coil, through a transistor array such as a ULN2003 or an H-bridge.

Position

A signed step counter for step-and-direction driver chips.

Sequencer

A position in a drive sequence, walked one step at a time.

StepDir

A stepper behind a step/direction driver chip such as an A4988 or a DRV8825.

Enums

Direction

Which way to step.

Drive

A stepper drive pattern.

Constants

DEFAULT_PULSE_MICROS

The width of a step pulse a step/direction driver starts with, in microseconds.

DEFAULT_STEP_MICROS

The pause between steps a driver starts with, in microseconds.

Functions

steps_for_degrees

Converts an angle to a whole number of steps for a given motor.