Adam Resnick / Servo

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Dependents:   CNCAirbrushCode

Servo.cpp@0:9e53989bcf57, 2012-04-28 (annotated)

Committer:
stretch
Date:
Sat Apr 28 21:08:24 2012 +0000
Revision:
0:9e53989bcf57
Initial Public Release

Who changed what in which revision?

UserRevisionLine numberNew contents of line
stretch 0:9e53989bcf57 1 /* mbed R/C Servo Library
stretch 0:9e53989bcf57 2 *
stretch 0:9e53989bcf57 3 * Copyright (c) 2007-2010 sford, cstyles
stretch 0:9e53989bcf57 4 *
stretch 0:9e53989bcf57 5 * Permission is hereby granted, free of charge, to any person obtaining a copy
stretch 0:9e53989bcf57 6 * of this software and associated documentation files (the "Software"), to deal
stretch 0:9e53989bcf57 7 * in the Software without restriction, including without limitation the rights
stretch 0:9e53989bcf57 8 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
stretch 0:9e53989bcf57 9 * copies of the Software, and to permit persons to whom the Software is
stretch 0:9e53989bcf57 10 * furnished to do so, subject to the following conditions:
stretch 0:9e53989bcf57 11 *
stretch 0:9e53989bcf57 12 * The above copyright notice and this permission notice shall be included in
stretch 0:9e53989bcf57 13 * all copies or substantial portions of the Software.
stretch 0:9e53989bcf57 14 *
stretch 0:9e53989bcf57 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
stretch 0:9e53989bcf57 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
stretch 0:9e53989bcf57 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
stretch 0:9e53989bcf57 18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
stretch 0:9e53989bcf57 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
stretch 0:9e53989bcf57 20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
stretch 0:9e53989bcf57 21 * THE SOFTWARE.
stretch 0:9e53989bcf57 22 */
stretch 0:9e53989bcf57 23
stretch 0:9e53989bcf57 24 #include "Servo.h"
stretch 0:9e53989bcf57 25 #include "mbed.h"
stretch 0:9e53989bcf57 26
stretch 0:9e53989bcf57 27 static float clamp(float value, float min, float max) {
stretch 0:9e53989bcf57 28 if(value < min) {
stretch 0:9e53989bcf57 29 return min;
stretch 0:9e53989bcf57 30 } else if(value > max) {
stretch 0:9e53989bcf57 31 return max;
stretch 0:9e53989bcf57 32 } else {
stretch 0:9e53989bcf57 33 return value;
stretch 0:9e53989bcf57 34 }
stretch 0:9e53989bcf57 35 }
stretch 0:9e53989bcf57 36
stretch 0:9e53989bcf57 37 Servo::Servo(PinName pin) : _pwm(pin) {
stretch 0:9e53989bcf57 38 calibrate();
stretch 0:9e53989bcf57 39 write(0.5);
stretch 0:9e53989bcf57 40 }
stretch 0:9e53989bcf57 41
stretch 0:9e53989bcf57 42 void Servo::calibrate(float range, float degrees, float center) {
stretch 0:9e53989bcf57 43 _range = range;
stretch 0:9e53989bcf57 44 _degrees = degrees;
stretch 0:9e53989bcf57 45 _center = center;
stretch 0:9e53989bcf57 46 }
stretch 0:9e53989bcf57 47
stretch 0:9e53989bcf57 48 void Servo::write(float percent) {
stretch 0:9e53989bcf57 49 float offset = _range * 2.0 * (percent - 0.5);
stretch 0:9e53989bcf57 50 _pwm.pulsewidth(0.0015 + _center + clamp(offset, -_range, _range));
stretch 0:9e53989bcf57 51 _p = clamp(percent, 0.0, 1.0);
stretch 0:9e53989bcf57 52 }
stretch 0:9e53989bcf57 53
stretch 0:9e53989bcf57 54 void Servo::position(float degrees) {
stretch 0:9e53989bcf57 55 float offset = _range * (degrees / _degrees);
stretch 0:9e53989bcf57 56 _pwm.pulsewidth(0.0015 + _center + clamp(offset, -_range, _range));
stretch 0:9e53989bcf57 57 }
stretch 0:9e53989bcf57 58
stretch 0:9e53989bcf57 59 float Servo::read() {
stretch 0:9e53989bcf57 60 return _p;
stretch 0:9e53989bcf57 61 }
stretch 0:9e53989bcf57 62
stretch 0:9e53989bcf57 63 Servo& Servo::operator= (float percent) {
stretch 0:9e53989bcf57 64 write(percent);
stretch 0:9e53989bcf57 65 return *this;
stretch 0:9e53989bcf57 66 }
stretch 0:9e53989bcf57 67
stretch 0:9e53989bcf57 68 Servo& Servo::operator= (Servo& rhs) {
stretch 0:9e53989bcf57 69 write(rhs.read());
stretch 0:9e53989bcf57 70 return *this;
stretch 0:9e53989bcf57 71 }
stretch 0:9e53989bcf57 72
stretch 0:9e53989bcf57 73 Servo::operator float() {
stretch 0:9e53989bcf57 74 return read();
stretch 0:9e53989bcf57 75 }