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Pi4J Java API & Runtime Library
package com.pi4j.io.spi.impl;
/*
* #%L
* **********************************************************************
* ORGANIZATION : Pi4J
* PROJECT : Pi4J :: Java Library (Core)
* FILENAME : SpiDeviceImpl.java
*
* This file is part of the Pi4J project. More information about
* this project can be found here: http://www.pi4j.com/
* **********************************************************************
* %%
* Copyright (C) 2012 - 2015 Pi4J
* %%
* This program 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 3 of the
* License, or (at your option) any later version.
*
* This program 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 Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
import com.pi4j.io.spi.SpiChannel;
import com.pi4j.io.spi.SpiDevice;
import com.pi4j.io.spi.SpiMode;
import com.pi4j.wiringpi.Spi;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
public class SpiDeviceImpl implements SpiDevice {
protected final SpiChannel channel;
protected final SpiMode mode;
/**
* Creates the SPI Device at the given spi and input channel
*
* @param channel
* spi channel to use
* @param speed
* spi speed/rate (in Hertz) for channel to communicate at
* (range is 500kHz - 32MHz)
* @param mode
* spi mode (see http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus#Mode_numbers)
*
*/
public SpiDeviceImpl(SpiChannel channel, int speed, SpiMode mode) throws IOException {
this.channel = channel;
this.mode = mode;
try {
int fd = Spi.wiringPiSPISetupMode(channel.getChannel(), speed, mode.getMode());
if (fd <= -1) {
throw new IOException("SPI port setup failed, wiringPiSPISetupMode returned " + fd);
}
} catch (UnsatisfiedLinkError e) {
throw new IOException("SPI port setup failed, no SPI available.", e);
}
}
/**
* Creates the SPI Device at the given spi and input channel
*
* @param channel
* spi channel to use
* @param speed
* spi speed/rate (in Hertz) for channel to communicate at
* (range is 500kHz - 32MHz)
*/
public SpiDeviceImpl(SpiChannel channel, int speed) throws IOException {
this(channel, speed, DEFAULT_SPI_MODE);
}
/**
* Creates the SPI Device at the given SPI and input channel
* (A default speed of 1 MHz will be used)
*
* @param channel
* spi channel to use
* @param mode
* spi mode (see http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus#Mode_numbers)
*/
public SpiDeviceImpl(SpiChannel channel, SpiMode mode) throws IOException {
this(channel, DEFAULT_SPI_SPEED, mode);
}
/**
* Creates the SPI Device at the given SPI and input channel
* (A default speed of 1 MHz will be used)
*
* @param channel
* spi channel to use
*/
public SpiDeviceImpl(SpiChannel channel) throws IOException {
this(channel, DEFAULT_SPI_SPEED);
}
@Override
public String write(String data, String charset) throws IOException {
byte[] buffer = data.getBytes(charset);
return new String(write(buffer), charset);
}
@Override
public String write(String data, Charset charset) throws IOException {
byte[] buffer = data.getBytes(charset);
return new String(write(buffer), charset);
}
@Override
public ByteBuffer write(ByteBuffer data) throws IOException {
return ByteBuffer.wrap(write(data.array()));
}
@Override
public byte[] write(InputStream input) throws IOException {
// ensure bytes are available
if(input.available() <= 0){
throw new IOException("No available bytes in input stream to write to SPI channel: " + channel.getChannel());
}
else if(input.available() > MAX_SUPPORTED_BYTES){
throw new IOException("Number of bytes in stream exceed the maximum bytes allowed to write SPI channel in a single call");
}
// create a temporary buffer to store read bytes from stream
byte[] buffer = new byte[MAX_SUPPORTED_BYTES];
// read maximum number of supported bytes
int length = input.read(buffer, 0 , MAX_SUPPORTED_BYTES);
// write bytes to SPI channel
return write(buffer, 0, length);
}
@Override
public int write(InputStream input, OutputStream output) throws IOException {
// write stream data to SPI device
byte[] buffer = write(input);
//write resulting byte array to output stream
output.write(buffer);
// return data length
return buffer.length;
}
@Override
public byte[] write(byte... data) throws IOException {
return write(data, 0, data.length);
}
@Override
public short[] write(short... data) throws IOException {
return write(data, 0, data.length);
}
@Override
public byte[] write(byte[] data, int start, int length) throws IOException {
// ensure the length does not exceed the data array
length = Math.min(data.length - start, length);
// validate max length allowed
if (length > MAX_SUPPORTED_BYTES) {
throw new IOException("Number of bytes in data to write exceed the maximum bytes allowed to write SPI channel in a single call");
}
// we make a copy of the data argument because we don't want to modify the original source data
byte[] buffer = new byte[length];
System.arraycopy(data, start, buffer, 0, length);
synchronized (channel) {
// write the bytes from the temporary buffer to the SPI channel
if (Spi.wiringPiSPIDataRW(channel.getChannel(), buffer) <= 0) {
throw new IOException("Failed to write data to SPI channel: " + channel.getChannel());
}
}
// return the updated byte buffer as the SPI read results
return buffer;
}
@Override
public short[] write(short[] data, int start, int length) throws IOException {
// ensure the length does not exceed the data array
length = Math.min(data.length - start, length);
// validate max length allowed
if (length > MAX_SUPPORTED_BYTES) {
throw new IOException("Number of bytes in data to write exceed the maximum bytes allowed to write SPI channel in a single call");
}
// we make a copy of the data argument because we don't want to modify the original source data
short[] buffer = new short[length];
System.arraycopy(data, start, buffer, 0, length);
synchronized (channel) {
// write the bytes from the temporary buffer to the SPI channel
if (Spi.wiringPiSPIDataRW(channel.getChannel(), buffer) <= 0) {
throw new IOException("Failed to write data to SPI channel: " + channel.getChannel());
}
// return the updated byte buffer as the SPI read results
return buffer;
}
}
}
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