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package com.pi4j.wiringpi;
/*
* #%L
* **********************************************************************
ORGANIZATION : Pi4J
PROJECT : Pi4J :: Java Library (Core)
FILENAME : Spi.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 - 2018 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.util.NativeLibraryLoader;
/**
*
* WiringPi includes a library which can make it easier to use the Raspberry Pi�s on-board SPI interface.
*
*
*
* Before you can use SPI interface, you may need to use the gpio utility to load the SPI drivers into the kernel:
* > gpio load spi
*
* If you need a buffer size of greater than 4KB, then you can specify the size (in KB) on the command line:
* > gpio load spi 100
*
* will allocate a 100KB buffer. (You should rarely need this though, the default is more than enough
* for most applications).
*
*
*
*
This library depends on the wiringPi native system library. (developed by
* Gordon Henderson @ http://wiringpi.com)
*
*
*
* @see http://www.pi4j.com
* @see http://wiringpi.com/reference/spi-library
* @author Robert Savage (http://www.savagehomeautomation.com)
*/
public class Spi {
public static int CHANNEL_0 = 0;
public static int CHANNEL_1 = 1;
public static int MODE_0 = 0;
public static int MODE_1 = 1;
public static int MODE_2 = 2;
public static int MODE_3 = 3;
// private constructor
private Spi() {
// forbid object construction
}
static {
// Load the platform library
NativeLibraryLoader.load("libpi4j.so");
}
/**
* wiringPiSPISetup:
*
*
* This is the way to initialise a channel (The Pi has 2 channels; 0 and 1). The speed parameter is an integer in
* the range 500,000 through 32,000,000 and represents the SPI clock speed in Hz.
*
*
*
* The returned value is the Linux file-descriptor for the device, or -1 on error. If an error has happened, you
* may use the standard errno global variable to see why.
*
*
* @see http://wiringpi.com/reference/spi-library
* @param channel SPI channel
* @param speed SPI speed
* @return return -1 on error
*/
public static native int wiringPiSPISetup(int channel, int speed);
/**
* wiringPiSPISetupMode:
*
*
* This is the way to initialise a channel (The Pi has 2 channels; 0 and 1). The speed parameter is an integer in
* the range 500,000 through 32,000,000 and represents the SPI clock speed in Hz.
*
*
*
* The returned value is the Linux file-descriptor for the device, or -1 on error. If an error has happened, you
* may use the standard errno global variable to see why.
*
*
* @see http://wiringpi.com/reference/spi-library
* @see http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus#Mode_numbers
* @param channel SPI channel
* @param speed SPI speed
* @param mode SPI mode (Mode is 0, 1, 2 or 3; see http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus#Mode_numbers)
* @return return -1 on error
*/
public static native int wiringPiSPISetupMode (int channel, int speed, int mode);
/**
* wiringPiSPIGetFd:
*
*
* Return the file-descriptor for the given channel
*
*
* @see http://wiringpi.com/reference/spi-library
* @param channel SPI channel
* @return file-descriptor for the given channel
*/
public static native int wiringPiSPIGetFd(int channel);
/**
* wiringPiSPIDataRW:
*
*
* This performs a simultaneous write/read transaction over the selected SPI bus. Data that was in your buffer is
* overwritten by data returned from the SPI bus.
*
*
*
* (ATTENTION: the 'data' argument can only be a maximum of 1024 characters.)
*
*
* @see http://wiringpi.com/reference/spi-library
* @param channel SPI channel
* @param data string data payload
* @return return -1 on error
*/
public static int wiringPiSPIDataRW(int channel, String data){
return wiringPiSPIDataRW(channel, data, data.length());
}
/**
* wiringPiSPIDataRW:
*
*
* This performs a simultaneous write/read transaction over the selected SPI bus. Data that was in your buffer is
* overwritten by data returned from the SPI bus.
*
*
*
* (ATTENTION: the 'data' argument can only be a maximum of 1024 characters.)
*
*
* @see http://wiringpi.com/reference/spi-library
* @param channel SPI channel
* @param data string data payload
* @param len length of characters in string (must be total string length, not a substring)
* @return return -1 on error
*/
public static native int wiringPiSPIDataRW(int channel, String data, int len);
/**
* wiringPiSPIDataRW:
*
*
* This performs a simultaneous write/read transaction over the selected SPI bus. Data that was in your buffer is
* overwritten by data returned from the SPI bus.
*
*
*
* (ATTENTION: the 'data' argument can only be a maximum of 1024 characters.)
*
*
* @see http://wiringpi.com/reference/spi-library
* @param channel
* SPI channel
* @param data
* byte array data payload
* @param len
* length of bytes in data array argument
* @return return -1 on error
*/
public static native int wiringPiSPIDataRW(int channel, byte[] data, int len);
/**
* wiringPiSPIDataRW:
*
*
* This performs a simultaneous write/read transaction over the selected SPI bus. Data that was in your buffer is
* overwritten by data returned from the SPI bus.
*
*
*
* (ATTENTION: the 'data' argument can only be a maximum of 1024 characters.)
*
*
* @see http://wiringpi.com/reference/spi-library
* @param channel
* SPI channel
* @param data
* byte array data payload
* @return return -1 on error
*/
public static int wiringPiSPIDataRW(int channel, byte[] data){
return wiringPiSPIDataRW(channel, data, data.length);
}
/**
*
* wiringPiSPIDataRW:
*
*
*
* This performs a simultaneous write/read transaction over the selected SPI bus. The data argument is passed into the wiringPI function as the argument and the output from Spi is returned by this
* method
*
*
* @see http://wiringpi.com/reference/spi-library
* @param channel
* SPI channel
* @param data
* short array data payload. Note that wiringPi uses unsigned char for the data transmission. That is 8-bit. in other words values 0-255. So make sure the values in data do not exceed
* this range, otherwise the numbers would overflow in the native code and unexpected results would yield
* @param len
* length of bytes in data array argument
* @return return -1 on error
*/
public static native int wiringPiSPIDataRW(int channel, short[] data, int len);
/**
*
* wiringPiSPIDataRW:
*
*
*
* This performs a simultaneous write/read transaction over the selected SPI bus. The data argument is passed into the wiringPI function as the argument and the output from Spi is returned by this
* method
*
*
* @see http://wiringpi.com/reference/spi-library
* @param channel
* SPI channel
* @param data
* short array data payload. Note that wiringPi uses unsigned char for the data transmission. That is 8-bit. in other words values 0-255. So make sure the values in data do not exceed
* this range, otherwise the numbers would overflow in the native code and unexpected results would yield
* @return return -1 on error
*/
public static int wiringPiSPIDataRW(int channel, short[] data){
return wiringPiSPIDataRW(channel, data, data.length);
}
}