Fer Pena
A class to control a model R/C servo, using a PwmOut
Fork of
Servo
by 
Simon Ford
Servo.cpp@0:24148c673250, 2009-11-16 (annotated)
- Committer:
- simon
- Date:
- Mon Nov 16 18:24:16 2009 +0000
- Revision:
- 0:24148c673250
- Child:
- 2:8995c167f399
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| simon | 0:24148c673250 | 1 | /* mbed R/C Servo |
| simon | 0:24148c673250 | 2 | * Copyright (c) 2007-2009 sford, cstyles |
| simon | 0:24148c673250 | 3 | * Released under the MIT License: http://mbed.org/license/mit |
| simon | 0:24148c673250 | 4 | */ |
| simon | 0:24148c673250 | 5 | |
| simon | 0:24148c673250 | 6 | #include "Servo.h" |
| simon | 0:24148c673250 | 7 | #include "mbed.h" |
| simon | 0:24148c673250 | 8 | |
| simon | 0:24148c673250 | 9 | static float clamp(float value, float min, float max) { |
| simon | 0:24148c673250 | 10 | if(value < min) { |
| simon | 0:24148c673250 | 11 | return min; |
| simon | 0:24148c673250 | 12 | } else if(value > max) { |
| simon | 0:24148c673250 | 13 | return max; |
| simon | 0:24148c673250 | 14 | } else { |
| simon | 0:24148c673250 | 15 | return value; |
| simon | 0:24148c673250 | 16 | } |
| simon | 0:24148c673250 | 17 | } |
| simon | 0:24148c673250 | 18 | |
| simon | 0:24148c673250 | 19 | Servo::Servo(PinName pin) : _pwm(pin) { |
| simon | 0:24148c673250 | 20 | calibrate(); |
| simon | 0:24148c673250 | 21 | write(0.5); |
| simon | 0:24148c673250 | 22 | } |
| simon | 0:24148c673250 | 23 | |
| simon | 0:24148c673250 | 24 | void Servo::write(float percent) { |
| simon | 0:24148c673250 | 25 | float offset = _range * 2.0 * (percent - 0.5); |
| simon | 0:24148c673250 | 26 | _pwm.pulsewidth(0.0015 + clamp(offset, -_range, _range)); |
| simon | 0:24148c673250 | 27 | _p = clamp(percent, 0.0, 1.0); |
| simon | 0:24148c673250 | 28 | } |
| simon | 0:24148c673250 | 29 | |
| simon | 0:24148c673250 | 30 | void Servo::position(float degrees) { |
| simon | 0:24148c673250 | 31 | float offset = _range * (degrees / _degrees); |
| simon | 0:24148c673250 | 32 | _pwm.pulsewidth(0.0015 + clamp(offset, -_range, _range)); |
| simon | 0:24148c673250 | 33 | } |
| simon | 0:24148c673250 | 34 | |
| simon | 0:24148c673250 | 35 | void Servo::calibrate(float range, float degrees) { |
| simon | 0:24148c673250 | 36 | _range = range; |
| simon | 0:24148c673250 | 37 | _degrees = degrees; |
| simon | 0:24148c673250 | 38 | } |
| simon | 0:24148c673250 | 39 | |
| simon | 0:24148c673250 | 40 | float Servo::read() { |
| simon | 0:24148c673250 | 41 | return _p; |
| simon | 0:24148c673250 | 42 | } |
| simon | 0:24148c673250 | 43 | |
| simon | 0:24148c673250 | 44 | Servo& Servo::operator= (float percent) { |
| simon | 0:24148c673250 | 45 | write(percent); |
| simon | 0:24148c673250 | 46 | return *this; |
| simon | 0:24148c673250 | 47 | } |
| simon | 0:24148c673250 | 48 | |
| simon | 0:24148c673250 | 49 | Servo& Servo::operator= (Servo& rhs) { |
| simon | 0:24148c673250 | 50 | write(rhs.read()); |
| simon | 0:24148c673250 | 51 | return *this; |
| simon | 0:24148c673250 | 52 | } |
| simon | 0:24148c673250 | 53 | |
| simon | 0:24148c673250 | 54 | Servo::operator float() { |
| simon | 0:24148c673250 | 55 | return read(); |
| simon | 0:24148c673250 | 56 | } |