/* -*- mode: java; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
Copyright (c) The Processing Foundation 2015
Hardware I/O library developed by Gottfried Haider
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General
Public License along with this library; if not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330,
Boston, MA 02111-1307 USA
*/
package processing.io;
import processing.core.*;
/**
* @webref
*/
public class SoftwareServo {
public static final int DEFAULT_MIN_PULSE = 544;
public static final int DEFAULT_MAX_PULSE = 2400;
protected int pin = -1; // gpio number (-1 .. not attached)
protected long handle = -1; // native thread id (<0 .. not started)
protected int period = 20000; // 20 ms (50 Hz)
protected int minPulse = 0; // minimum pulse width in microseconds
protected int maxPulse = 0; // maximum pulse width in microseconds
protected int pulse = 0; // current pulse in microseconds
/**
* Opens a servo motor
* @param parent typically use "this"
* @webref
*/
public SoftwareServo(PApplet parent) {
NativeInterface.loadLibrary();
}
/**
* Closes a servo motor
* @webref
*/
public void close() {
detach();
}
protected void finalize() throws Throwable {
try {
close();
} finally {
super.finalize();
}
}
/**
* Attaches a servo motor to a GPIO pin
* @param pin GPIO pin
* @webref
*/
public void attach(int pin) {
detach();
this.pin = pin;
this.minPulse = DEFAULT_MIN_PULSE;
this.maxPulse = DEFAULT_MAX_PULSE;
}
/**
* Attaches a servo motor to a GPIO pin using custom pulse widths
* @param minPulse minimum pulse width in microseconds (default: 544, same as on Arduino)
* @param maxPulse maximum pulse width in microseconds (default: 2400, same as on Arduino)
* @webref
*/
public void attach(int pin, int minPulse, int maxPulse) {
detach();
this.pin = pin;
this.minPulse = minPulse;
this.maxPulse = maxPulse;
}
/**
* Moves a servo motor to a given orientation
* @param angle angle in degrees (controls speed and direction on continuous-rotation servos)
* @webref
*/
public void write(float angle) {
if (attached() == false) {
System.err.println("You need to call attach(pin) before write(angle).");
throw new RuntimeException("Servo is not attached");
}
if (angle < 0 || 180 < angle) {
System.err.println("Only degree values between 0 and 180 can be used.");
throw new IllegalArgumentException("Illegal value");
}
pulse = (int)(minPulse + (angle/180.0) * (maxPulse-minPulse));
if (handle < 0) {
// start a new thread
GPIO.pinMode(pin, GPIO.OUTPUT);
if (NativeInterface.isSimulated()) {
return;
}
handle = NativeInterface.servoStartThread(pin, pulse, period);
if (handle < 0) {
throw new RuntimeException(NativeInterface.getError((int)handle));
}
} else {
// thread already running
int ret = NativeInterface.servoUpdateThread(handle, pulse, period);
if (ret < 0) {
throw new RuntimeException(NativeInterface.getError(ret));
}
}
}
/**
* Returns whether a servo motor is attached to a pin
* @return true if attached, false is not
* @webref
*/
public boolean attached() {
return (pin != -1);
}
/**
* Detatches a servo motor from a GPIO pin
* @webref
*/
public void detach() {
if (0 <= handle) {
// stop thread
int ret = NativeInterface.servoStopThread(handle);
GPIO.pinMode(pin, GPIO.INPUT);
handle = -1;
pin = -1;
if (ret < 0) {
throw new RuntimeException(NativeInterface.getError(ret));
}
}
}
}