001package com.pi4j.wiringpi; 002 003/* 004 * #%L 005 * ********************************************************************** 006 * ORGANIZATION : Pi4J 007 * PROJECT : Pi4J :: Java Library (Core) 008 * FILENAME : Shift.java 009 * 010 * This file is part of the Pi4J project. More information about 011 * this project can be found here: http://www.pi4j.com/ 012 * ********************************************************************** 013 * %% 014 * Copyright (C) 2012 - 2013 Pi4J 015 * %% 016 * Licensed under the Apache License, Version 2.0 (the "License"); 017 * you may not use this file except in compliance with the License. 018 * You may obtain a copy of the License at 019 * 020 * http://www.apache.org/licenses/LICENSE-2.0 021 * 022 * Unless required by applicable law or agreed to in writing, software 023 * distributed under the License is distributed on an "AS IS" BASIS, 024 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 025 * See the License for the specific language governing permissions and 026 * limitations under the License. 027 * #L% 028 */ 029 030 031import com.pi4j.util.NativeLibraryLoader; 032 033/** 034 * <h1>WiringPi Shift Library</h1> 035 * 036 * <p> 037 * WiringPi includes a shift library which more or less mimics the one in the Arduino system. This 038 * allows you to shift 8-bit data values out of the Pi, or into the Pi from devices such as 039 * shift-registers (e.g. 74,595) and so-on, although it can also be used in some bit-banging 040 * scenarios. 041 * </p> 042 * 043 * <p> 044 * Before using the Pi4J library, you need to ensure that the Java VM in configured with access to 045 * the following system libraries: 046 * <ul> 047 * <li>pi4j</li> 048 * <li>wiringPi</li> 049 * </ul> 050 * <blockquote> This library depends on the wiringPi native system library.</br> (developed by 051 * Gordon Henderson @ <a href="https://projects.drogon.net/">https://projects.drogon.net/</a>) 052 * </blockquote> 053 * </p> 054 * 055 * @see <a href="http://www.pi4j.com/">http://www.pi4j.com/</a> 056 * @see <a 057 * href="https://projects.drogon.net/raspberry-pi/wiringpi/shift-library/">https://projects.drogon.net/raspberry-pi/wiringpi/shift-library/</a> 058 * @author Robert Savage (<a 059 * href="http://www.savagehomeautomation.com">http://www.savagehomeautomation.com</a>) 060 */ 061public class Shift { 062 063 public static final int LSBFIRST = 0; 064 public static final int MSBFIRST = 1; 065 066 // private constructor 067 private Shift() { 068 // forbid object construction 069 } 070 071 static { 072 // Load the platform library 073 NativeLibraryLoader.load("pi4j", "libpi4j.so"); 074 } 075 076 /** 077 * <p>uint8_t shiftIn (uint8_t dPin, uint8_t cPin, uint8_t order);</p> 078 * 079 * <p> 080 * This shifts an 8-bit data value in with the data appearing on the dPin and the clock being 081 * sent out on the cPin. Order is either LSBFIRST or MSBFIRST. The data is sampled after the 082 * cPin goes high. (So cPin high, sample data, cPin low, repeat for 8 bits) The 8-bit value is 083 * returned by the function. 084 * </p> 085 * 086 * @see <a 087 * href="https://projects.drogon.net/raspberry-pi/wiringpi/shift-library/">https://projects.drogon.net/raspberry-pi/wiringpi/shift-library/</a> 088 * 089 * @param dPin 090 * @param cPin 091 * @param order 092 * @return <p> 093 * The 8-bit shifted value is returned by the function. 094 * </p> 095 */ 096 public static native byte shiftIn(byte dPin, byte cPin, byte order); 097 098 /** 099 * <p>void shiftOut (uint8_t dPin, uint8_t cPin, uint8_t order, uint8_t val);</p> 100 * 101 * <p> 102 * The shifts an 8-bit data value val out with the data being sent out on dPin and the clock 103 * being sent out on the cPin. order is as above. Data is clocked out on the rising or falling 104 * edge; ie. dPin is set, then cPin is taken high then low and repeated for the 8 bits. 105 * </p> 106 * 107 * @see <a 108 * href="https://projects.drogon.net/raspberry-pi/wiringpi/shift-library/">https://projects.drogon.net/raspberry-pi/wiringpi/shift-library/</a> 109 * 110 * @param dPin 111 * @param cPin 112 * @param order 113 * @param val 114 */ 115 public static native void shiftOut(byte dPin, byte cPin, byte order, byte val); 116}