polargraph_arduino/libraries/AccelStepper/AccelStepper.h

621 lines
32 KiB
C++

// AccelStepper.h
//
/// \mainpage AccelStepper library for Arduino
///
/// This is the Arduino AccelStepper library.
/// It provides an object-oriented interface for 2, 3 or 4 pin stepper motors.
///
/// The standard Arduino IDE includes the Stepper library
/// (http://arduino.cc/en/Reference/Stepper) for stepper motors. It is
/// perfectly adequate for simple, single motor applications.
///
/// AccelStepper significantly improves on the standard Arduino Stepper library in several ways:
/// \li Supports acceleration and deceleration
/// \li Supports multiple simultaneous steppers, with independent concurrent stepping on each stepper
/// \li API functions never delay() or block
/// \li Supports 2, 3 and 4 wire steppers, plus 3 and 4 wire half steppers.
/// \li Supports alternate stepping functions to enable support of AFMotor (https://github.com/adafruit/Adafruit-Motor-Shield-library)
/// \li Supports stepper drivers such as the Sparkfun EasyDriver (based on 3967 driver chip)
/// \li Very slow speeds are supported
/// \li Extensive API
/// \li Subclass support
///
/// The latest version of this documentation can be downloaded from
/// http://www.airspayce.com/mikem/arduino/AccelStepper
/// The version of the package that this documentation refers to can be downloaded
/// from http://www.airspayce.com/mikem/arduino/AccelStepper/AccelStepper-1.38.zip
///
/// Example Arduino programs are included to show the main modes of use.
///
/// You can also find online help and discussion at http://groups.google.com/group/accelstepper
/// Please use that group for all questions and discussions on this topic.
/// Do not contact the author directly, unless it is to discuss commercial licensing.
///
/// Tested on Arduino Diecimila and Mega with arduino-0018 & arduino-0021
/// on OpenSuSE 11.1 and avr-libc-1.6.1-1.15,
/// cross-avr-binutils-2.19-9.1, cross-avr-gcc-4.1.3_20080612-26.5.
///
/// \par Installation
/// Install in the usual way: unzip the distribution zip file to the libraries
/// sub-folder of your sketchbook.
///
/// \par Theory
/// This code uses speed calculations as described in
/// "Generate stepper-motor speed profiles in real time" by David Austin
/// http://fab.cba.mit.edu/classes/MIT/961.09/projects/i0/Stepper_Motor_Speed_Profile.pdf
/// with the exception that AccelStepper uses steps per second rather than radians per second
/// (because we dont know the step angle of the motor)
/// An initial step interval is calculated for the first step, based on the desired acceleration
/// On subsequent steps, shorter step intervals are calculated based
/// on the previous step until max speed is achieved.
///
/// This software is Copyright (C) 2010 Mike McCauley. Use is subject to license
/// conditions. The main licensing options available are GPL V2 or Commercial:
///
/// \par Open Source Licensing GPL V2
/// This is the appropriate option if you want to share the source code of your
/// application with everyone you distribute it to, and you also want to give them
/// the right to share who uses it. If you wish to use this software under Open
/// Source Licensing, you must contribute all your source code to the open source
/// community in accordance with the GPL Version 2 when your application is
/// distributed. See http://www.gnu.org/copyleft/gpl.html
///
/// \par Commercial Licensing
/// This is the appropriate option if you are creating proprietary applications
/// and you are not prepared to distribute and share the source code of your
/// application. Contact info@airspayce.com for details.
///
/// \par Revision History
/// \version 1.0 Initial release
///
/// \version 1.1 Added speed() function to get the current speed.
/// \version 1.2 Added runSpeedToPosition() submitted by Gunnar Arndt.
/// \version 1.3 Added support for stepper drivers (ie with Step and Direction inputs) with _pins == 1
/// \version 1.4 Added functional contructor to support AFMotor, contributed by Limor, with example sketches.
/// \version 1.5 Improvements contributed by Peter Mousley: Use of microsecond steps and other speed improvements
/// to increase max stepping speed to about 4kHz. New option for user to set the min allowed pulse width.
/// Added checks for already running at max speed and skip further calcs if so.
/// \version 1.6 Fixed a problem with wrapping of microsecond stepping that could cause stepping to hang.
/// Reported by Sandy Noble.
/// Removed redundant _lastRunTime member.
/// \version 1.7 Fixed a bug where setCurrentPosition() did not always work as expected.
/// Reported by Peter Linhart.
/// \version 1.8 Added support for 4 pin half-steppers, requested by Harvey Moon
/// \version 1.9 setCurrentPosition() now also sets motor speed to 0.
/// \version 1.10 Builds on Arduino 1.0
/// \version 1.11 Improvments from Michael Ellison:
/// Added optional enable line support for stepper drivers
/// Added inversion for step/direction/enable lines for stepper drivers
/// \version 1.12 Announce Google Group
/// \version 1.13 Improvements to speed calculation. Cost of calculation is now less in the worst case,
/// and more or less constant in all cases. This should result in slightly beter high speed performance, and
/// reduce anomalous speed glitches when other steppers are accelerating.
/// However, its hard to see how to replace the sqrt() required at the very first step from 0 speed.
/// \version 1.14 Fixed a problem with compiling under arduino 0021 reported by EmbeddedMan
/// \version 1.15 Fixed a problem with runSpeedToPosition which did not correctly handle
/// running backwards to a smaller target position. Added examples
/// \version 1.16 Fixed some cases in the code where abs() was used instead of fabs().
/// \version 1.17 Added example ProportionalControl
/// \version 1.18 Fixed a problem: If one calls the funcion runSpeed() when Speed is zero, it makes steps
/// without counting. reported by Friedrich, Klappenbach.
/// \version 1.19 Added MotorInterfaceType and symbolic names for the number of pins to use
/// for the motor interface. Updated examples to suit.
/// Replaced individual pin assignment variables _pin1, _pin2 etc with array _pin[4].
/// _pins member changed to _interface.
/// Added _pinInverted array to simplify pin inversion operations.
/// Added new function setOutputPins() which sets the motor output pins.
/// It can be overridden in order to provide, say, serial output instead of parallel output
/// Some refactoring and code size reduction.
/// \version 1.20 Improved documentation and examples to show need for correctly
/// specifying AccelStepper::FULL4WIRE and friends.
/// \version 1.21 Fixed a problem where desiredSpeed could compute the wrong step acceleration
/// when _speed was small but non-zero. Reported by Brian Schmalz.
/// Precompute sqrt_twoa to improve performance and max possible stepping speed
/// \version 1.22 Added Bounce.pde example
/// Fixed a problem where calling moveTo(), setMaxSpeed(), setAcceleration() more
/// frequently than the step time, even
/// with the same values, would interfere with speed calcs. Now a new speed is computed
/// only if there was a change in the set value. Reported by Brian Schmalz.
/// \version 1.23 Rewrite of the speed algorithms in line with
/// http://fab.cba.mit.edu/classes/MIT/961.09/projects/i0/Stepper_Motor_Speed_Profile.pdf
/// Now expect smoother and more linear accelerations and decelerations. The desiredSpeed()
/// function was removed.
/// \version 1.24 Fixed a problem introduced in 1.23: with runToPosition, which did never returned
/// \version 1.25 Now ignore attempts to set acceleration to 0.0
/// \version 1.26 Fixed a problem where certina combinations of speed and accelration could cause
/// oscillation about the target position.
/// \version 1.27 Added stop() function to stop as fast as possible with current acceleration parameters.
/// Also added new Quickstop example showing its use.
/// \version 1.28 Fixed another problem where certain combinations of speed and accelration could cause
/// oscillation about the target position.
/// Added support for 3 wire full and half steppers such as Hard Disk Drive spindle.
/// Contributed by Yuri Ivatchkovitch.
/// \version 1.29 Fixed a problem that could cause a DRIVER stepper to continually step
/// with some sketches. Reported by Vadim.
/// \version 1.30 Fixed a problem that could cause stepper to back up a few steps at the end of
/// accelerated travel with certain speeds. Reported and patched by jolo.
/// \version 1.31 Updated author and distribution location details to airspayce.com
/// \version 1.32 Fixed a problem with enableOutputs() and setEnablePin on Arduino Due that
/// prevented the enable pin changing stae correctly. Reported by Duane Bishop.
/// \version 1.33 Fixed an error in example AFMotor_ConstantSpeed.pde did not setMaxSpeed();
/// Fixed a problem that caused incorrect pin sequencing of FULL3WIRE and HALF3WIRE.
/// Unfortunately this meant changing the signature for all step*() functions.
/// Added example MotorShield, showing how to use AdaFruit Motor Shield to control
/// a 3 phase motor such as a HDD spindle motor (and without using the AFMotor library.
/// \version 1.34 Added setPinsInverted(bool pin1Invert, bool pin2Invert, bool pin3Invert, bool pin4Invert, bool enableInvert)
/// to allow inversion of 2, 3 and 4 wire stepper pins. Requested by Oleg.
/// \version 1.35 Removed default args from setPinsInverted(bool, bool, bool, bool, bool) to prevent ambiguity with
/// setPinsInverted(bool, bool, bool). Reported by Mac Mac.
/// \version 1.36 Changed enableOutputs() and disableOutputs() to be virtual so can be overridden.
/// Added new optional argument 'enable' to constructor, which allows you toi disable the
/// automatic enabling of outputs at construction time. Suggested by Guido.
/// \version 1.37 Fixed a problem with step1 that could cause a rogue step in the
/// wrong direction (or not,
/// depending on the setup-time requirements of the connected hardware).
/// Reported by Mark Tillotson.
/// \version 1.38 run() function incorrectly always returned true. Updated function and doc so it returns true
/// if the motor is still running to the target position.
///
/// \author Mike McCauley (mikem@airspayce.com) DO NOT CONTACT THE AUTHOR DIRECTLY: USE THE LISTS
// Copyright (C) 2009-2013 Mike McCauley
// $Id: AccelStepper.h,v 1.19 2013/08/02 01:53:21 mikem Exp mikem $
#ifndef AccelStepper_h
#define AccelStepper_h
#include <stdlib.h>
#if ARDUINO >= 100
#include <Arduino.h>
#else
#include <WProgram.h>
#include <wiring.h>
#endif
// These defs cause trouble on some versions of Arduino
#undef round
/////////////////////////////////////////////////////////////////////
/// \class AccelStepper AccelStepper.h <AccelStepper.h>
/// \brief Support for stepper motors with acceleration etc.
///
/// This defines a single 2 or 4 pin stepper motor, or stepper moter with fdriver chip, with optional
/// acceleration, deceleration, absolute positioning commands etc. Multiple
/// simultaneous steppers are supported, all moving
/// at different speeds and accelerations.
///
/// \par Operation
/// This module operates by computing a step time in microseconds. The step
/// time is recomputed after each step and after speed and acceleration
/// parameters are changed by the caller. The time of each step is recorded in
/// microseconds. The run() function steps the motor once if a new step is due.
/// The run() function must be called frequently until the motor is in the
/// desired position, after which time run() will do nothing.
///
/// \par Positioning
/// Positions are specified by a signed long integer. At
/// construction time, the current position of the motor is consider to be 0. Positive
/// positions are clockwise from the initial position; negative positions are
/// anticlockwise. The curent position can be altered for instance after
/// initialization positioning.
///
/// \par Caveats
/// This is an open loop controller: If the motor stalls or is oversped,
/// AccelStepper will not have a correct
/// idea of where the motor really is (since there is no feedback of the motor's
/// real position. We only know where we _think_ it is, relative to the
/// initial starting point).
///
/// \par Performance
/// The fastest motor speed that can be reliably supported is about 4000 steps per
/// second at a clock frequency of 16 MHz on Arduino such as Uno etc.
/// Faster processors can support faster stepping speeds.
/// However, any speed less than that
/// down to very slow speeds (much less than one per second) are also supported,
/// provided the run() function is called frequently enough to step the motor
/// whenever required for the speed set.
/// Calling setAcceleration() is expensive,
/// since it requires a square root to be calculated.
class AccelStepper
{
public:
/// \brief Symbolic names for number of pins.
/// Use this in the pins argument the AccelStepper constructor to
/// provide a symbolic name for the number of pins
/// to use.
typedef enum
{
FUNCTION = 0, ///< Use the functional interface, implementing your own driver functions (internal use only)
DRIVER = 1, ///< Stepper Driver, 2 driver pins required
FULL2WIRE = 2, ///< 2 wire stepper, 2 motor pins required
FULL3WIRE = 3, ///< 3 wire stepper, such as HDD spindle, 3 motor pins required
FULL4WIRE = 4, ///< 4 wire full stepper, 4 motor pins required
HALF3WIRE = 6, ///< 3 wire half stepper, such as HDD spindle, 3 motor pins required
HALF4WIRE = 8 ///< 4 wire half stepper, 4 motor pins required
} MotorInterfaceType;
/// Constructor. You can have multiple simultaneous steppers, all moving
/// at different speeds and accelerations, provided you call their run()
/// functions at frequent enough intervals. Current Position is set to 0, target
/// position is set to 0. MaxSpeed and Acceleration default to 1.0.
/// The motor pins will be initialised to OUTPUT mode during the
/// constructor by a call to enableOutputs().
/// \param[in] interface Number of pins to interface to. 1, 2, 4 or 8 are
/// supported, but it is preferred to use the \ref MotorInterfaceType symbolic names.
/// AccelStepper::DRIVER (1) means a stepper driver (with Step and Direction pins).
/// If an enable line is also needed, call setEnablePin() after construction.
/// You may also invert the pins using setPinsInverted().
/// AccelStepper::FULL2WIRE (2) means a 2 wire stepper (2 pins required).
/// AccelStepper::FULL3WIRE (3) means a 3 wire stepper, such as HDD spindle (3 pins required).
/// AccelStepper::FULL4WIRE (4) means a 4 wire stepper (4 pins required).
/// AccelStepper::HALF3WIRE (6) means a 3 wire half stepper, such as HDD spindle (3 pins required)
/// AccelStepper::HALF4WIRE (8) means a 4 wire half stepper (4 pins required)
/// Defaults to AccelStepper::FULL4WIRE (4) pins.
/// \param[in] pin1 Arduino digital pin number for motor pin 1. Defaults
/// to pin 2. For a AccelStepper::DRIVER (pins==1),
/// this is the Step input to the driver. Low to high transition means to step)
/// \param[in] pin2 Arduino digital pin number for motor pin 2. Defaults
/// to pin 3. For a AccelStepper::DRIVER (pins==1),
/// this is the Direction input the driver. High means forward.
/// \param[in] pin3 Arduino digital pin number for motor pin 3. Defaults
/// to pin 4.
/// \param[in] pin4 Arduino digital pin number for motor pin 4. Defaults
/// to pin 5.
/// \param[in] enable If this is true (the default), enableOutpuys() will be called to enable
/// the output pins at construction time.
AccelStepper(uint8_t interface = AccelStepper::FULL4WIRE, uint8_t pin1 = 2, uint8_t pin2 = 3, uint8_t pin3 = 4, uint8_t pin4 = 5, bool enable = true);
/// Alternate Constructor which will call your own functions for forward and backward steps.
/// You can have multiple simultaneous steppers, all moving
/// at different speeds and accelerations, provided you call their run()
/// functions at frequent enough intervals. Current Position is set to 0, target
/// position is set to 0. MaxSpeed and Acceleration default to 1.0.
/// Any motor initialization should happen before hand, no pins are used or initialized.
/// \param[in] forward void-returning procedure that will make a forward step
/// \param[in] backward void-returning procedure that will make a backward step
AccelStepper(void (*forward)(), void (*backward)());
/// Set the target position. The run() function will try to move the motor (at most one step per call)
/// from the current position to the target position set by the most
/// recent call to this function. Caution: moveTo() also recalculates the speed for the next step.
/// If you are trying to use constant speed movements, you should call setSpeed() after calling moveTo().
/// \param[in] absolute The desired absolute position. Negative is
/// anticlockwise from the 0 position.
virtual void moveTo(long absolute);
/// Set the target position relative to the current position
/// \param[in] relative The desired position relative to the current position. Negative is
/// anticlockwise from the current position.
void move(long relative);
/// Poll the motor and step it if a step is due, implementing
/// accelerations and decelerations to acheive the target position. You must call this as
/// frequently as possible, but at least once per minimum step time interval,
/// preferably in your main loop. Note that each call to run() will make at most one step, and then only when a step is due,
/// based on the current speed and the time since the last step.
/// \return true if the motor is still running to the target position.
boolean run();
/// Poll the motor and step it if a step is due, implementing a constant
/// speed as set by the most recent call to setSpeed(). You must call this as
/// frequently as possible, but at least once per step interval,
/// \return true if the motor was stepped.
virtual boolean runSpeed();
/// Sets the maximum permitted speed. The run() function will accelerate
/// up to the speed set by this function.
/// \param[in] speed The desired maximum speed in steps per second. Must
/// be > 0. Caution: Speeds that exceed the maximum speed supported by the processor may
/// Result in non-linear accelerations and decelerations.
void setMaxSpeed(float speed);
/// Sets the acceleration/deceleration rate.
/// \param[in] acceleration The desired acceleration in steps per second
/// per second. Must be > 0.0. This is an expensive call since it requires a square
/// root to be calculated. Dont call more ofthen than needed
void setAcceleration(float acceleration);
/// Sets the desired constant speed for use with runSpeed().
/// \param[in] speed The desired constant speed in steps per
/// second. Positive is clockwise. Speeds of more than 1000 steps per
/// second are unreliable. Very slow speeds may be set (eg 0.00027777 for
/// once per hour, approximately. Speed accuracy depends on the Arduino
/// crystal. Jitter depends on how frequently you call the runSpeed() function.
void setSpeed(float speed);
/// The most recently set speed
/// \return the most recent speed in steps per second
float speed();
/// The distance from the current position to the target position.
/// \return the distance from the current position to the target position
/// in steps. Positive is clockwise from the current position.
long distanceToGo();
/// The most recently set target position.
/// \return the target position
/// in steps. Positive is clockwise from the 0 position.
long targetPosition();
/// The currently motor position.
/// \return the current motor position
/// in steps. Positive is clockwise from the 0 position.
long currentPosition();
/// Resets the current position of the motor, so that wherever the motor
/// happens to be right now is considered to be the new 0 position. Useful
/// for setting a zero position on a stepper after an initial hardware
/// positioning move.
/// Has the side effect of setting the current motor speed to 0.
/// \param[in] position The position in steps of wherever the motor
/// happens to be right now.
void setCurrentPosition(long position);
/// Moves the motor at the currently selected constant speed (forward or reverse)
/// to the target position and blocks until it is at
/// position. Dont use this in event loops, since it blocks.
void runToPosition();
/// Runs at the currently selected speed until the target position is reached
/// Does not implement accelerations.
/// \return true if it stepped
virtual boolean runSpeedToPosition();
/// Moves the motor to the new target position and blocks until it is at
/// position. Dont use this in event loops, since it blocks.
/// \param[in] position The new target position.
void runToNewPosition(long position);
/// Sets a new target position that causes the stepper
/// to stop as quickly as possible, using to the current speed and acceleration parameters.
void stop();
/// Disable motor pin outputs by setting them all LOW
/// Depending on the design of your electronics this may turn off
/// the power to the motor coils, saving power.
/// This is useful to support Arduino low power modes: disable the outputs
/// during sleep and then reenable with enableOutputs() before stepping
/// again.
virtual void disableOutputs();
/// Enable motor pin outputs by setting the motor pins to OUTPUT
/// mode. Called automatically by the constructor.
virtual void enableOutputs();
/// Sets the minimum pulse width allowed by the stepper driver. The minimum practical pulse width is
/// approximately 20 microseconds. Times less than 20 microseconds
/// will usually result in 20 microseconds or so.
/// \param[in] minWidth The minimum pulse width in microseconds.
void setMinPulseWidth(unsigned int minWidth);
/// Sets the enable pin number for stepper drivers.
/// 0xFF indicates unused (default).
/// Otherwise, if a pin is set, the pin will be turned on when
/// enableOutputs() is called and switched off when disableOutputs()
/// is called.
/// \param[in] enablePin Arduino digital pin number for motor enable
/// \sa setPinsInverted
void setEnablePin(uint8_t enablePin = 0xff);
/// Sets the inversion for stepper driver pins
/// \param[in] directionInvert True for inverted direction pin, false for non-inverted
/// \param[in] stepInvert True for inverted step pin, false for non-inverted
/// \param[in] enableInvert True for inverted enable pin, false (default) for non-inverted
void setPinsInverted(bool directionInvert = false, bool stepInvert = false, bool enableInvert = false);
/// Sets the inversion for 2, 3 and 4 wire stepper pins
/// \param[in] pin1Invert True for inverted pin1, false for non-inverted
/// \param[in] pin2Invert True for inverted pin2, false for non-inverted
/// \param[in] pin3Invert True for inverted pin3, false for non-inverted
/// \param[in] pin4Invert True for inverted pin4, false for non-inverted
/// \param[in] enableInvert True for inverted enable pin, false (default) for non-inverted
void setPinsInverted(bool pin1Invert, bool pin2Invert, bool pin3Invert, bool pin4Invert, bool enableInvert);
protected:
/// \brief Direction indicator
/// Symbolic names for the direction the motor is turning
typedef enum
{
DIRECTION_CCW = 0, ///< Clockwise
DIRECTION_CW = 1 ///< Counter-Clockwise
} Direction;
/// Forces the library to compute a new instantaneous speed and set that as
/// the current speed. It is called by
/// the library:
/// \li after each step
/// \li after change to maxSpeed through setMaxSpeed()
/// \li after change to acceleration through setAcceleration()
/// \li after change to target position (relative or absolute) through
/// move() or moveTo()
void computeNewSpeed();
/// Low level function to set the motor output pins
/// bit 0 of the mask corresponds to _pin[0]
/// bit 1 of the mask corresponds to _pin[1]
/// You can override this to impment, for example serial chip output insted of using the
/// output pins directly
virtual void setOutputPins(uint8_t mask);
/// Called to execute a step. Only called when a new step is
/// required. Subclasses may override to implement new stepping
/// interfaces. The default calls step1(), step2(), step4() or step8() depending on the
/// number of pins defined for the stepper.
/// \param[in] step The current step phase number (0 to 7)
virtual void step(long step);
/// Called to execute a step using stepper functions (pins = 0) Only called when a new step is
/// required. Calls _forward() or _backward() to perform the step
/// \param[in] step The current step phase number (0 to 7)
virtual void step0(long step);
/// Called to execute a step on a stepper driver (ie where pins == 1). Only called when a new step is
/// required. Subclasses may override to implement new stepping
/// interfaces. The default sets or clears the outputs of Step pin1 to step,
/// and sets the output of _pin2 to the desired direction. The Step pin (_pin1) is pulsed for 1 microsecond
/// which is the minimum STEP pulse width for the 3967 driver.
/// \param[in] step The current step phase number (0 to 7)
virtual void step1(long step);
/// Called to execute a step on a 2 pin motor. Only called when a new step is
/// required. Subclasses may override to implement new stepping
/// interfaces. The default sets or clears the outputs of pin1 and pin2
/// \param[in] step The current step phase number (0 to 7)
virtual void step2(long step);
/// Called to execute a step on a 3 pin motor, such as HDD spindle. Only called when a new step is
/// required. Subclasses may override to implement new stepping
/// interfaces. The default sets or clears the outputs of pin1, pin2,
/// pin3
/// \param[in] step The current step phase number (0 to 7)
virtual void step3(long step);
/// Called to execute a step on a 4 pin motor. Only called when a new step is
/// required. Subclasses may override to implement new stepping
/// interfaces. The default sets or clears the outputs of pin1, pin2,
/// pin3, pin4.
/// \param[in] step The current step phase number (0 to 7)
virtual void step4(long step);
/// Called to execute a step on a 3 pin motor, such as HDD spindle. Only called when a new step is
/// required. Subclasses may override to implement new stepping
/// interfaces. The default sets or clears the outputs of pin1, pin2,
/// pin3
/// \param[in] step The current step phase number (0 to 7)
virtual void step6(long step);
/// Called to execute a step on a 4 pin half-steper motor. Only called when a new step is
/// required. Subclasses may override to implement new stepping
/// interfaces. The default sets or clears the outputs of pin1, pin2,
/// pin3, pin4.
/// \param[in] step The current step phase number (0 to 7)
virtual void step8(long step);
//private:
/// Number of pins on the stepper motor. Permits 2 or 4. 2 pins is a
/// bipolar, and 4 pins is a unipolar.
uint8_t _interface; // 0, 1, 2, 4, 8, See MotorInterfaceType
/// Arduino pin number assignments for the 2 or 4 pins required to interface to the
/// stepper motor or driver
uint8_t _pin[4];
/// Whether the _pins is inverted or not
uint8_t _pinInverted[4];
/// The current absolution position in steps.
long _currentPos; // Steps
/// The target position in steps. The AccelStepper library will move the
/// motor from the _currentPos to the _targetPos, taking into account the
/// max speed, acceleration and deceleration
long _targetPos; // Steps
/// The current motos speed in steps per second
/// Positive is clockwise
float _speed; // Steps per second
/// The maximum permitted speed in steps per second. Must be > 0.
float _maxSpeed;
/// The acceleration to use to accelerate or decelerate the motor in steps
/// per second per second. Must be > 0
float _acceleration;
float _sqrt_twoa; // Precomputed sqrt(2*_acceleration)
/// The current interval between steps in microseconds.
/// 0 means the motor is currently stopped with _speed == 0
unsigned long _stepInterval;
/// The last step time in microseconds
unsigned long _lastStepTime;
/// The minimum allowed pulse width in microseconds
unsigned int _minPulseWidth;
/// Is the direction pin inverted?
///bool _dirInverted; /// Moved to _pinInverted[1]
/// Is the step pin inverted?
///bool _stepInverted; /// Moved to _pinInverted[0]
/// Is the enable pin inverted?
bool _enableInverted;
/// Enable pin for stepper driver, or 0xFF if unused.
uint8_t _enablePin;
/// The pointer to a forward-step procedure
void (*_forward)();
/// The pointer to a backward-step procedure
void (*_backward)();
/// The step counter for speed calculations
long _n;
/// Initial step size in microseconds
float _c0;
/// Last step size in microseconds
float _cn;
/// Min step size in microseconds based on maxSpeed
float _cmin; // at max speed
/// Current direction motor is spinning in
boolean _direction; // 1 == CW
};
/// @example Random.pde
/// Make a single stepper perform random changes in speed, position and acceleration
/// @example Overshoot.pde
/// Check overshoot handling
/// which sets a new target position and then waits until the stepper has
/// achieved it. This is used for testing the handling of overshoots
/// @example MultiStepper.pde
/// Shows how to multiple simultaneous steppers
/// Runs one stepper forwards and backwards, accelerating and decelerating
/// at the limits. Runs other steppers at the same time
/// @example ConstantSpeed.pde
/// Shows how to run AccelStepper in the simplest,
/// fixed speed mode with no accelerations
/// @example Blocking.pde
/// Shows how to use the blocking call runToNewPosition
/// Which sets a new target position and then waits until the stepper has
/// achieved it.
/// @example AFMotor_MultiStepper.pde
/// Control both Stepper motors at the same time with different speeds
/// and accelerations.
/// @example AFMotor_ConstantSpeed.pde
/// Shows how to run AccelStepper in the simplest,
/// fixed speed mode with no accelerations
/// @example ProportionalControl.pde
/// Make a single stepper follow the analog value read from a pot or whatever
/// The stepper will move at a constant speed to each newly set posiiton,
/// depending on the value of the pot.
/// @example Bounce.pde
/// Make a single stepper bounce from one limit to another, observing
/// accelrations at each end of travel
/// @example Quickstop.pde
/// Check stop handling.
/// Calls stop() while the stepper is travelling at full speed, causing
/// the stepper to stop as quickly as possible, within the constraints of the
/// current acceleration.
/// @example MotorShield.pde
/// Shows how to use AccelStepper to control a 3-phase motor, such as a HDD spindle motor
/// using the Adafruit Motor Shield http://www.ladyada.net/make/mshield/index.html.
#endif