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215 | -- Services for the Allegro A4988 Stepper Motor Driver
-- Copyright (C)2021, Philip Munts, President, Munts AM Corp.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are met:
--
-- * Redistributions of source code must retain the above copyright notice,
-- this list of conditions and the following disclaimer.
--
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-- ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-- POSSIBILITY OF SUCH DAMAGE.
-- NOTE: This package bit-bangs the step signal to the A4988 driver. For more
-- accurate timing, you should generate the step signal from some kind of
-- dedicated real-time hardware, such as a microcontroller.
WITH Ada.Calendar;
WITH GPIO;
WITH Stepper;
USE TYPE Ada.Calendar.Time;
USE TYPE GPIO.Pin;
USE TYPE Stepper.Rate;
USE TYPE Stepper.Steps;
PACKAGE BODY A4988 IS
microseconds : CONSTANT Duration := 1.0E-6;
milliseconds : CONSTANT Duration := 1.0E-3;
-- A4988 device object constructors
FUNCTION Create
(Steps : Stepper.Steps; -- Number of steps per rotation
Rate : Stepper.Rate; -- Default step rate (Hertz)
Step : NOT NULL GPIO.Pin;
Dir : NOT NULL GPIO.Pin;
Enable : GPIO.Pin := NULL;
Reset : GPIO.Pin := NULL;
Sleep : GPIO.Pin := NULL) RETURN Device IS
dev : DeviceClass;
BEGIN
Initialize(dev, Steps, Rate, Step, Dir, Enable, Reset, Sleep);
RETURN NEW DeviceClass'(dev);
END Create;
FUNCTION Create
(Steps : Stepper.Steps; -- Number of steps per rotation
Rate : Stepper.Rate; -- Default step rate (Hertz)
Step : NOT NULL GPIO.Pin;
Dir : NOT NULL GPIO.Pin;
Enable : GPIO.Pin := NULL;
Reset : GPIO.Pin := NULL;
Sleep : GPIO.Pin := NULL) RETURN Stepper.Output IS
dev : DeviceClass;
BEGIN
Initialize(dev, Steps, Rate, Step, Dir, Enable, Reset, Sleep);
RETURN NEW DeviceClass'(dev);
END Create;
-- A4988 device object initializer
PROCEDURE Initialize
(Self : IN OUT DeviceClass;
Steps : Stepper.Steps; -- Number of steps per rotation
Rate : Stepper.Rate; -- Default step rate (Hertz)
Step : NOT NULL GPIO.Pin;
Dir : NOT NULL GPIO.Pin;
Enable : GPIO.Pin := NULL;
Reset : GPIO.Pin := NULL;
Sleep : GPIO.Pin := NULL) IS
BEGIN
-- Validate parameters
IF Steps < 1 THEN
RAISE Stepper.Error WITH "Invalid number of steps per rotation";
END IF;
IF Rate <= 0.0 THEN
RAISE Standard.Stepper.Error WITH "Invalid value for rate";
END IF;
Step.Put(False);
Dir.Put(False);
Self.numsteps := Steps;
Self.steprate := Rate;
Self.step_pin := Step;
Self.dir_pin := Dir;
Self.enable_pin := Enable;
Self.reset_pin := Reset;
Self.sleep_pin := Sleep;
Self.Reset;
Self.Disable;
Self.Sleep;
Self.Wakeup;
Self.Enable;
END Initialize;
-- Stepper interface methods
PROCEDURE Put
(Self : IN OUT DeviceClass;
steps : Stepper.Steps) IS
BEGIN
Put(Self, steps, Self.steprate);
END Put;
PROCEDURE Put
(Self : IN OUT DeviceClass;
steps : Stepper.Steps;
rate : Stepper.Rate) IS
interval : CONSTANT Duration := 1.0/Duration(rate);
nexttime : Ada.Calendar.Time := Ada.Calendar.Clock;
BEGIN
-- Validate parameters
IF Rate <= 0.0 THEN
RAISE Standard.Stepper.Error WITH "Invalid value for rate";
END IF;
IF steps > 0 THEN
Self.dir_pin.Put(True); -- Forward (nominal, depends on motor wiring)
ELSIF steps < 0 THEN
Self.dir_pin.Put(False); -- Reverse (nominal, depends on motor wiring)
ELSE
RETURN;
END IF;
-- NOTE: Exact timing for the step pulse train will be determined by the
-- resolution of the DELAY statement on the target platform.
FOR n IN 1 .. ABS steps LOOP
Self.step_pin.Put(True);
DELAY 2.0*microseconds; -- Datasheet typical minimum is 1 microsecond
Self.step_pin.Put(False);
nexttime := nexttime + interval;
DELAY nexttime - Ada.Calendar.Clock;
END LOOP;
END Put;
FUNCTION StepsPerRotation(Self : IN OUT DeviceClass) RETURN Stepper.Steps IS
BEGIN
RETURN Self.numsteps;
END StepsPerRotation;
-- Other methods
PROCEDURE Enable(Self : DeviceClass) IS
BEGIN
IF Self.enable_pin /= NULL THEN
Self.enable_pin.Put(False);
END IF;
END Enable;
PROCEDURE Disable(Self : DeviceClass) IS
BEGIN
IF Self.enable_pin /= NULL THEN
Self.enable_pin.Put(True);
END IF;
END Disable;
PROCEDURE Reset(Self : DeviceClass) IS
BEGIN
IF Self.reset_pin /= NULL THEN
Self.reset_pin.Put(False);
DELAY 1.0*microseconds;
Self.reset_pin.Put(True);
DELAY 1.0*microseconds;
END IF;
END Reset;
PROCEDURE Sleep(Self : DeviceClass) IS
BEGIN
IF Self.sleep_pin /= NULL THEN
Self.sleep_pin.Put(False);
END IF;
END Sleep;
PROCEDURE Wakeup(Self : DeviceClass) IS
BEGIN
IF Self.sleep_pin /= NULL THEN
Self.sleep_pin.Put(True);
DELAY 1.0*milliseconds; -- Wait for charge pump to stabilize
END IF;
END Wakeup;
END A4988;
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