Servo.cpp

00001 /* mbed simple Servo controller
00002  * Copyright (c) 2019, marcel.bernet@ch-open.ch
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 "mbed.h"
00024 #include "Servo.h"
00025 
00026 
00027 
00028 Servo::Servo(PinName pin) : _pwm(pin)
00029 {
00030     _pwm.period_ms(20);
00031     write(0.5);
00032 }
00033 
00034 void Servo::write(float percent)
00035 {
00036     _p = percent;
00037     float p = percent * (SERVO_MAX-SERVO_MIN) + SERVO_MIN;
00038     p = (p < SERVO_MIN) ? SERVO_MIN : p;
00039     p = (p > SERVO_MAX) ? SERVO_MAX : p;
00040     _pwm.pulsewidth_us( (int) p );
00041 }
00042 
00043 float Servo::read()
00044 {
00045     return _p;
00046 }
00047 
00048 Servo& Servo::operator= (float percent)
00049 {
00050     write(percent);
00051     return *this;
00052 }
00053 
00054 Servo& Servo::operator= (Servo& rhs)
00055 {
00056     write(rhs.read());
00057     return *this;
00058 }
00059 
00060 Servo::operator float()
00061 {
00062     return read();
00063 }
00064 
00065 
00066