Motor.h

00001 /* mbed simple H-bridge motor controller
00002  * Copyright (c) 2007-2010, sford
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020  * THE SOFTWARE.
00021  */
00022 
00023 #ifndef MBED_MOTOR_H
00024 #define MBED_MOTOR_H
00025 
00026 #include "mbed.h"
00027 
00028 #define BRAKE_HIGH 1
00029 #define BRAKE_LOW  0
00030 
00031 /** Interface to control a standard DC motor 
00032  * with an H-bridge using a PwmOut and 2 DigitalOuts
00033  */
00034 class Motor {
00035 public:
00036 
00037     /** Create a motor control interface    
00038      *
00039      * @param pwm A PwmOut pin, driving the H-bridge enable line to control the speed
00040      * @param fwd A DigitalOut, set high when the motor should go forward
00041      * @param rev A DigitalOut, set high when the motor should go backwards
00042      */
00043     Motor(PinName pwm, PinName fwd, PinName rev);
00044     
00045     /** Set the speed of the motor
00046      * 
00047      * @param speed The speed of the motor as a normalised value between -1.0 and 1.0
00048      */
00049     void speed(float speed);
00050     
00051     /** Set the period of the pwm duty cycle.
00052      *
00053      * Wrapper for PwmOut::period()
00054      *
00055      * @param seconds - Pwm duty cycle in seconds.
00056      */
00057     void period(float period);
00058     
00059     /** Brake the H-bridge to GND or VCC.
00060      * 
00061      * Defaults to breaking to VCC.
00062      *
00063      * Brake to GND => inA = inB = 0
00064      * Brake to VCC => inA = inB = 1
00065      */
00066     void brake(int highLow = BRAKE_LOW);
00067 
00068 protected:
00069     PwmOut _pwm;
00070     DigitalOut _fwd;
00071     DigitalOut _rev;
00072 
00073 };
00074 
00075 #endif