net.freeutils.scrollphat.Pi4JDevice Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jscrollphat-core Show documentation
The newest version!
/*
 *  Copyright © 2016 Amichai Rothman
 *
 *  This file is part of JScrollPhat - the Java Scroll pHAT package.
 *
 *  JScrollPhat is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  JScrollPhat 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with JScrollPhat.  If not, see .
 *
 *  For additional info see http://www.freeutils.net/source/jscrollphat/
 */

package net.freeutils.scrollphat;

import java.io.IOException;
import com.pi4j.io.i2c.I2CBus;
import com.pi4j.io.i2c.I2CDevice;
import com.pi4j.io.i2c.I2CFactory;

/**
 * A Device implementation that uses Pi4J for the
 * low-level I2C communications with the device.
 * 
 * This implementation requires the Pi4J library to be
 * available on the classpath (its native JNI library
 * is conveniently embedded in the jar itself.)
 *
 * @see Pi4J Website
 */
public class Pi4JDevice extends Device {

    protected I2CBus bus;
    protected I2CDevice device;

    @Override
    protected Device openImpl(int busNumber, int address) throws IOException {
        try {
            this.bus = I2CFactory.getInstance(busNumber);
            this.device = bus.getDevice(address);
        } catch (I2CFactory.UnsupportedBusNumberException ubne) {
            throw new IOException("error getting I2C bus: " + ubne);
        }
        return this;
    }

    @Override
    protected void closeImpl() throws IOException {
        if (device != null)
            reset();
        device = null;
        if (bus != null)
            bus.close();
        bus = null;
    }

    @Override
    protected void writeImpl(byte register, int data) throws IOException {
        device.write(register, (byte)data);
    }

    @Override
    protected void writeImpl(byte register, byte[] data, int offset, int length) throws IOException {
        device.write(register, data, offset, length);
    }
}