l298: Initial implementation

This was tested on the RobotBase Dual H-Bridge motor control board.

There are two examples:

l298-example: This example demonstrates using the class to contol one
of the H-Brdges to control a DC motor.

l298-stepper-example: This example demonstrates using the class to
control a 4-wire dual-phase stepper motor.

Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: Zion Orent <zorent@ics.com>
Signed-off-by: John Van Drasek <john.r.van.drasek@intel.com>

src/l298/l298.h

@@ -0,0 +1,184 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2015 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#pragma once
+
+#include <stdint.h>
+#include <sys/time.h>
+
+#include <mraa/gpio.h>
+#include <mraa/pwm.h>
+
+// in milliseconds
+#define L298_DEFAULT_PWM_PERIOD 4
+
+namespace upm {
+
+  /**
+   * @brief C++ API for the L298 Dual H-Bridge module
+   * @defgroup l298 libupm-l298
+   */
+
+  /**
+   * @brief UPM module for the L298 Dual H-Bridge
+   *
+   * It was developed using the RobotBase Dual H-Bridge module.
+   *
+   * This module can support 2 DC motors, or 1 2-phase stepper motor.
+   * It requires 3 pins per DC motor (or h-bridge), or 4 pins for
+   * the stepper (uses both h-bridges).  
+   *
+   * @ingroup l298 pwm gpio
+   * Example driving a DC motor
+   * @snippet l298.cxx Interesting
+   * Example driving a stepper motor
+   * @snippet l298-stepper.cxx Interesting
+   */
+
+
+  class L298 {
+  public:
+
+    /**
+     * Enum to specify the direction of a motor
+     */
+    typedef enum {
+      DIR_NONE = 0x00,
+      DIR_CW   = 0x01,
+      DIR_CCW  = 0x02
+    } L298_DIRECTION_T;
+
+    /**
+     * L298 constructor for DC motor(s) connected.  
+     *
+     * @param pwm digital pin to use for DC motor - must be PWM capable
+     * @param dir1 digital pin to use for motor direction pin 1
+     * @param dir2 digital pin to use for motor direction pin 2
+     */
+    L298(int pwm, int dir1, int dir2);
+
+    /**
+     * L298 constructor for 4-wire stepper motor
+     *
+     * @param stepsPerRev number of steps per full revolution
+     * @param en enable pin
+     * @param i1 digital pin to use for stepper input 1
+     * @param i2 digital pin to use for stepper input 2
+     * @param i3 digital pin to use for stepper input 3
+     * @param i4 digital pin to use for stepper input 4
+     */
+    L298(int stepsPerRev, int en, int i1, int i2, int i3, int i4);
+
+    /**
+     * L298 Destructor
+     */
+    ~L298();
+
+    /**
+     * Return the number of milliseconds elapsed since initClock()
+     * was last called.
+     *
+     * @return elapsed milliseconds
+     */
+    uint32_t getMillis();
+
+    /**
+     * Reset the Clock
+     *
+     */
+    void initClock();
+
+    /**
+     * set the period in milliseconds
+     *
+     * @param ms period in milliseconds
+     */
+    void setPeriodMS(int ms);
+
+    /**
+     * enable PWM output for a motor
+     *
+     * @param enable enable PWM output if true, disable if false
+     */
+    void enable(bool enable);
+
+    /**
+     * set the speed of a DC or stepp motor.  For a DC motor, Values
+     * can range from 0 (off) to 100 (full speed).  For a stepper
+     * motor, specify the desired RPM.
+     *
+     * @param speed speed to set the motor to
+     */
+    void setSpeed(int speed);
+
+    /**
+     * set the direction of the motor, clockwise or counter clockwise
+     *
+     * @param dir direction to set the motor to
+     */
+    void setDirection(L298_DIRECTION_T dir);
+
+    /**
+     * step the stepper motor a specified number of steps
+     *
+     * @param steps number of steps to move the stepper motor
+     */
+    void stepperSteps(unsigned int steps);
+
+  private:
+    // DC motor mode enabled
+    bool m_motor;
+    // stepper mode enabled
+    bool m_stepper;
+
+    struct timeval m_startTime;
+
+    // DC motor
+    mraa_pwm_context m_pwm;
+    mraa_gpio_context m_dir1;
+    mraa_gpio_context m_dir2;
+
+    // stepper (4-wire)
+    mraa_gpio_context m_stepEnable;
+    mraa_gpio_context m_stepI1;
+    mraa_gpio_context m_stepI2;
+    mraa_gpio_context m_stepI3;
+    mraa_gpio_context m_stepI4;
+
+    // steps per revolution
+    int m_stepsPerRev;
+    int m_currentStep;
+    uint32_t m_stepDelay;
+
+    /**
+     * step the motor one tick
+     *
+     */
+    void stepperStep();
+
+    // step direction - 1 = forward, -1 = backward
+    int m_stepDirection;
+  };
+}
+
+