Control a DC motor via a standard H-bridge using a PwmOut pin to control speed and two DigitalOut pins to control direction. Can change pwm period on the PwmOut pin, and also brake high or low.

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Show/hide line numbers Motor.cpp Source File

Motor.cpp

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 #include "Motor.h"
00024 
00025 Motor::Motor(PinName pwm, PinName fwd, PinName rev):
00026         _pwm(pwm), _fwd(fwd), _rev(rev) {
00027 
00028     // Set initial condition of PWM
00029     _pwm.period(0.001);
00030     _pwm = 0;
00031 
00032     // Initial condition of output enables
00033     _fwd = 0;
00034     _rev = 0;
00035 }
00036 
00037 void Motor::speed(float speed) {
00038     _fwd = (speed > 0.0);
00039     _rev = (speed < 0.0);
00040     _pwm = abs(speed);
00041 }
00042 
00043 void Motor::period(float period){
00044 
00045     _pwm.period(period);
00046 
00047 }
00048 
00049 void Motor::brake(int highLow){
00050 
00051     if(highLow == BRAKE_HIGH){
00052         _fwd = 1;
00053         _rev = 1;
00054     }
00055     else if(highLow == BRAKE_LOW){
00056         _fwd = 0;
00057         _rev = 0;
00058     }
00059 
00060 }