RadioHead.h

// RadioHead.h
// Author: Mike McCauley (mikem@airspayce.com) DO NOT CONTACT THE AUTHOR DIRECTLY
// Copyright (C) 2014 Mike McCauley
// $Id: RadioHead.h,v 1.54 2016/01/02 01:46:34 mikem Exp mikem $

/// \mainpage RadioHead Packet Radio library for embedded microprocessors
///
/// This is the RadioHead Packet Radio library for embedded microprocessors.
/// It provides a complete object-oriented library for sending and receiving packetized messages
/// via a variety of common data radios and other transports on a range of embedded microprocessors.
///
/// The version of the package that this documentation refers to can be downloaded 
/// from http://www.airspayce.com/mikem/arduino/RadioHead/RadioHead-1.57.zip
/// You can find the latest version at http://www.airspayce.com/mikem/arduino/RadioHead
///
/// You can also find online help and discussion at 
/// http://groups.google.com/group/radiohead-arduino
/// Please use that group for all questions and discussions on this topic. 
/// Do not contact the author directly, unless it is to discuss commercial licensing.
/// Before asking a question or reporting a bug, please read 
/// - http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/How_to_ask_a_software_question
/// - http://www.catb.org/esr/faqs/smart-questions.html
/// - http://www.chiark.greenend.org.uk/~shgtatham/bugs.html
///
/// \par Overview
///
/// RadioHead consists of 2 main sets of classes: Drivers and Managers.
///
/// - Drivers provide low level access to a range of different packet radios and other packetized message transports.
/// - Managers provide high level message sending and receiving facilities for a range of different requirements.
///
/// Every RadioHead program will have an instance of a Driver to provide access to the data radio or transport, 
/// and a Manager that uses that driver to send and receive messages for the application. The programmer is required
/// to instantiate a Driver and a Manager, and to initialise the Manager. Thereafter the facilities of the Manager
/// can be used to send and receive messages.
///
/// It is also possible to use a Driver on its own, without a Manager, although this only allows unaddressed, 
/// unreliable transport via the Driver's facilities.
///
/// In some specialised use cases, it is possible to instantiate more than one Driver and more than one Manager.
///
/// A range of different common embedded microprocessor platforms are supported, allowing your project to run
/// on your choice of processor.
///
/// Example programs are included to show the main modes of use.
///
/// \par Drivers
///
/// The following Drivers are provided:
///
/// - RH_RF22
/// Works with Hope-RF
/// RF22B and RF23B based transceivers, and compatible chips and modules, 
/// including the RFM22B transceiver module such as 
/// this bare module: http://www.sparkfun.com/products/10153
/// and this shield: http://www.sparkfun.com/products/11018 
/// and this board: http://www.anarduino.com/miniwireless
/// and RF23BP modules such as: http://www.anarduino.com/details.jsp?pid=130
/// Supports GFSK, FSK and OOK. Access to other chip 
/// features such as on-chip temperature measurement, analog-digital 
/// converter, transmitter power control etc is also provided.
///
/// - RH_RF24
/// Works with Silicon Labs Si4460/4461/4463/4464 family of transceivers chip, and the equivalent
/// HopeRF RF24/26/27 family of chips and the HopeRF RFM24W/26W/27W modules.
/// Supports GFSK, FSK and OOK. Access to other chip 
/// features such as on-chip temperature measurement, analog-digital 
/// converter, transmitter power control etc is also provided.
///
/// - RH_RF69 
/// Works with Hope-RF
/// RF69B based radio modules, such as the RFM69 module, (as used on the excellent Moteino and Moteino-USB 
/// boards from LowPowerLab http://lowpowerlab.com/moteino/ )
/// and compatible chips and modules such as RFM69W, RFM69HW, RFM69CW, RFM69HCW (Semtech SX1231, SX1231H).
/// Also works with Anarduino MiniWireless -CW and -HW boards http://www.anarduino.com/miniwireless/ including
/// the marvellous high powered MinWireless-HW (with 20dBm output for excellent range).
/// Supports GFSK, FSK.
///
/// - RH_NRF24
/// Works with Nordic nRF24 based 2.4GHz radio modules, such as nRF24L01 and others.
/// Also works with Hope-RF RFM73 
/// and compatible devices (such as BK2423). nRF24L01 and RFM73 can interoperate
/// with each other.
///
/// - RH_NRF905
/// Works with Nordic nRF905 based 433/868/915 MHz radio modules.
///
/// - RH_NRF51
/// Works with Nordic nRF51 compatible 2.4 GHz SoC/devices such as the nRF51822.
///
/// - RH_RF95
/// Works with Semtech SX1276/77/78/79, Modtronix inAir4 and inAir9,
/// and HopeRF RFM95/96/97/98 and other similar LoRa capable radios.
/// Supports Long Range (LoRa) with spread spectrum frequency hopping, large payloads etc.
/// FSK/GFSK/OOK modes are not (yet) supported.
///
/// - RH_MRF89
/// Works with Microchip MRF89XA and compatible transceivers.
/// and modules such as MRF89XAM9A.
///
/// - RH_CC110
/// Works with Texas Instruments CC110L transceivers and compatible modules such as Anaren AIR BoosterPack 430BOOST-CC110L
///
/// - RH_ASK
/// Works with a range of inexpensive ASK (amplitude shift keying) RF transceivers such as RX-B1 
/// (also known as ST-RX04-ASK) receiver; TX-C1 transmitter and DR3100 transceiver; FS1000A/XY-MK-5V transceiver;
/// HopeRF RFM83C / RFM85. Supports ASK (OOK).
///
/// - RH_Serial
/// Works with RS232, RS422, RS485, RS488 and other point-to-point and multidropped serial connections, 
/// or with TTL serial UARTs such as those on Arduino and many other processors,
/// or with data radios with a 
/// serial port interface. RH_Serial provides packetization and error detection over any hardware or 
/// virtual serial connection. Also builds and runs on Linux and OSX.
///
/// - RH_TCP
/// For use with simulated sketches compiled and running on Linux.
/// Works with tools/etherSimulator.pl to pass messages between simulated sketches, allowing
/// testing of Manager classes on Linux and without need for real radios or other transport hardware.
///
/// Drivers can be used on their own to provide unaddressed, unreliable datagrams. 
/// All drivers have the same identical API.
/// Or you can use any Driver with any of the Managers described below.
///
/// We welcome contributions of well tested and well documented code to support other transports.
///
/// \par Managers
///
/// The following Mangers are provided:
///
/// - RHDatagram
/// Addressed, unreliable variable length messages, with optional broadcast facilities.
///
/// - RHReliableDatagram
/// Addressed, reliable, retransmitted, acknowledged variable length messages.
///
/// - RHRouter
/// Multi-hop delivery from source node to destination node via 0 or more intermediate nodes, with manual routing.
///
/// - RHMesh
/// Multi-hop delivery with automatic route discovery and rediscovery.
///
/// Any Manager may be used with any Driver.
///
/// \par Platforms
/// 
/// A range of platforms is supported:
///
/// - Arduino and the Arduino IDE (version 1.0 to 1.6.5 and later)
/// Including Diecimila, Uno, Mega, Leonardo, Yun, Due, Zero etc. http://arduino.cc/, Also similar boards such as 
///  - Moteino http://lowpowerlab.com/moteino/ 
///  - Anarduino Mini http://www.anarduino.com/mini/ 
///  - RedBearLab Blend V1.0 http://redbearlab.com/blend/ (with Arduino 1.0.5 and RedBearLab Blend Add-On version 20140701) 
///  -  MoteinoMEGA https://lowpowerlab.com/shop/moteinomega 
///     (with Arduino 1.0.5 and the MoteinoMEGA Arduino Core 
///     https://github.com/LowPowerLab/Moteino/tree/master/MEGA/Core)
///  - ESP8266 on Arduino IDE and Boards Manager per https://github.com/esp8266/Arduino 
///    Tested using Arduino 1.6.5 with esp8266 by ESP8266 Community version 2.0.0
///    Examples serial_reliable_datagram_* and ask_* are shown to work. 
///    CAUTION: SPI not supported yet. The GHz radio included in the ESP8266 is
///    not yet supported. 
///  - etc.
///
/// - ChipKit Uno32 board and the MPIDE development environment
/// http://www.digilentinc.com/Products/Detail.cfm?Prod=CHIPKIT-UNO32
///
/// - Maple and Flymaple boards with libmaple and the Maple-IDE development environment
/// http://leaflabs.com/devices/maple/ and http://www.open-drone.org/flymaple
///
/// - Teensy including Teensy 3.1 and earlier built using Arduino IDE 1.0.5 to 1.6.4 and later with 
///   teensyduino addon 1.18 to 1.23 and later.
///   http://www.pjrc.com/teensy
///
/// - Particle Photon https://store.particle.io/collections/photon and ARM3 based CPU with built-in 
///   Wi-Fi transceiver and extensive IoT software suport. RadioHead does not support the built-in transceiver
///   bt can be used to control other SPI based radios, Serial ports etc.
///   See below for details on how to build RadioHead for Photon
///
/// - ATtiny built using Arduino IDE 1.0.5 with the arduino-tiny support from https://code.google.com/p/arduino-tiny/
///   and Digispark built with Arduino 1.6.5.
///   (Caution: these are very small processors and not all RadioHead features may be available, depending on memory requirements)
///
/// - nRF51 compatible Arm chips such as nRF51822 with Arduino 1.6.4 and later using the procedures
///   in http://redbearlab.com/getting-started-nrf51822/
///
/// - Raspberry Pi
///   Uses BCM2835 library for GPIO http://www.airspayce.com/mikem/bcm2835/
///   Currently works only with RH_NRF24 driver or other drivers that do not require interrupt support.
///   Contributed by Mike Poublon.
///
/// - Linux and OSX
///   Using the RHutil/HardwareSerial class, the RH_Serial driver and any manager will
///   build and run on Linux and OSX. These can be used to build programs that talk securely and reliably to
///   Arduino and other processors or to other Linux or OSX hosts on a reliable, error detected datagram
///   protocol over a serial line.
///
/// Other platforms are partially supported, such as Generic AVR 8 bit processors, MSP430. 
/// We welcome contributions that will expand the range of supported platforms. 
///
/// RadioHead is available (through the efforts of others) 
/// for PlatformIO. PlatformIO is a cross-platform code builder and the missing library manager.
/// http://platformio.org/#!/lib/show/124/RadioHead
///
/// \par History
///
/// RadioHead was created in April 2014, substantially based on code from some of our other earlier Radio libraries:
///
/// - RHMesh, RHRouter, RHReliableDatagram and RHDatagram are derived from the RF22 library version 1.39.
/// - RH_RF22 is derived from the RF22 library version 1.39.
/// - RH_RF69 is derived from the RF69 library version 1.2.
/// - RH_ASK is based on the VirtualWire library version 1.26, after significant conversion to C++.
/// - RH_Serial was new.
/// - RH_NRF24 is based on the NRF24 library version 1.12, with some significant changes.
///
/// During this combination and redevelopment, we have tried to retain all the processor dependencies and support from
/// the libraries that were contributed by other people. However not all platforms can be tested by us, so if you
/// find that support from some platform has not been successfully migrated, please feel free to fix it and send us a 
/// patch.
///
/// Users of RHMesh, RHRouter, RHReliableDatagram and RHDatagram in the previous RF22 library will find that their
/// existing code will run mostly without modification. See the RH_RF22 documentation for more details.
///
/// \par Installation
///
/// Install in the usual way: unzip the distribution zip file to the libraries
/// sub-folder of your sketchbook. 
/// The example sketches will be visible in in your Arduino, mpide, maple-ide or whatever.
/// http://arduino.cc/en/Guide/Libraries
///
/// \par Building for Particle Photon
///
/// The Photon is not supported by the Arduino IDE, so it takes a little effort to set up a build environment.
/// Heres what we did to enable building of RadioHead example sketches on Linux, 
/// but there are other ways to skin this cat.
/// Basic reference for getting stated is: http://particle-firmware.readthedocs.org/en/develop/build/
/// - Download the ARM gcc cross compiler binaries and unpack it in a suitable place:
/// \code
/// cd /tmp
/// wget https://launchpad.net/gcc-arm-embedded/5.0/5-2015-q4-major/+download/gcc-arm-none-eabi-5_2-2015q4-20151219-linux.tar.bz2
/// tar xvf gcc-arm-none-eabi-5_2-2015q4-20151219-linux.tar.bz2
/// \endcode
/// - If dfu-util and friends not installed on your platform, download dfu-util and friends to somewhere in your path
/// \code
/// cd ~/bin
/// wget http://dfu-util.sourceforge.net/releases/dfu-util-0.8-binaries/linux-i386/dfu-util
/// wget http://dfu-util.sourceforge.net/releases/dfu-util-0.8-binaries/linux-i386/dfu-suffix
/// wget http://dfu-util.sourceforge.net/releases/dfu-util-0.8-binaries/linux-i386/dfu-prefix
/// \endcode
/// - Download the Particle firmware (contains headers and libraries require to compile Photon sketches) 
///   to a suitable place:
/// \code
/// cd /tmp
/// wget https://github.com/spark/firmware/archive/develop.zip
/// unzip develop.zip
/// \endcode
/// - Make a working area containing the RadioHead library source code and your RadioHead sketch. You must
///   rename the sketch from .pde or .ino to application.cpp
/// \code
/// cd /tmp
/// mkdir RadioHead
/// cd RadioHead
/// cp /usr/local/projects/arduino/libraries/RadioHead/*.h .
/// cp /usr/local/projects/arduino/libraries/RadioHead/*.cpp .
/// cp /usr/local/projects/arduino/libraries/RadioHead/examples/cc110/cc110_client/cc110_client.pde application.cpp
/// \endcode
/// - Edit application.cpp and comment out any #include <SPI.h> so it looks like:
/// \code
///   // #include <SPI.h>
/// \endcode
/// - Connect your Photon by USB. Put it in DFU mode as descibed in Photon documentation. Light should be flashing yellow
/// - Compile the RadioHead sketch and install it as the user program (this does not update the rest of the
///   Photon firmware, just the user part:
/// \code
/// cd /tmp/firmware-develop/main
/// PATH=$PATH:/tmp/gcc-arm-none-eabi-5_2-2015q4/bin make APPDIR=/tmp/RadioHead all PLATFORM=photon program-dfu
/// \endcode
/// - You should see RadioHead compile without errors and download the finished sketch into the Photon.
///
/// \par Compatible Hardware Suppliers
///
/// We have had good experiences with the following suppliers of RadioHead compatible hardware:
///
/// - LittleBird http://littlebirdelectronics.com.au in Australia for all manner of Arduinos and radios.
/// - LowPowerLab http://lowpowerlab.com/moteino in USA for the excellent Moteino and Moteino-USB 
///   boards which include Hope-RF RF69B radios on-board.
/// - Anarduino and HopeRF USA (http://www.hoperfusa.com and http://www.anarduino.com) who have a wide range
///   of HopeRF radios and Arduino integrated modules.
/// - SparkFun https://www.sparkfun.com/ in USA who design and sell a wide range of Arduinos and radio modules.
///
/// \par Donations
///
/// This library is offered under a free GPL license for those who want to use it that way. 
/// We try hard to keep it up to date, fix bugs
/// and to provide free support. If this library has helped you save time or money, please consider donating at
/// http://www.airspayce.com or here:
///
/// \htmlonly <form action="https://www.paypal.com/cgi-bin/webscr" method="post"><input type="hidden" name="cmd" value="_donations" /> <input type="hidden" name="business" value="mikem@airspayce.com" /> <input type="hidden" name="lc" value="AU" /> <input type="hidden" name="item_name" value="Airspayce" /> <input type="hidden" name="item_number" value="RadioHead" /> <input type="hidden" name="currency_code" value="USD" /> <input type="hidden" name="bn" value="PP-DonationsBF:btn_donateCC_LG.gif:NonHosted" /> <input type="image" alt="PayPal — The safer, easier way to pay online." name="submit" src="https://www.paypalobjects.com/en_AU/i/btn/btn_donateCC_LG.gif" /> <img alt="" src="https://www.paypalobjects.com/en_AU/i/scr/pixel.gif" width="1" height="1" border="0" /></form> \endhtmlonly
/// 
/// \par Trademarks
///
/// RadioHead is a trademark of AirSpayce Pty Ltd. The RadioHead mark was first used on April 12 2014 for
/// international trade, and is used only in relation to data communications hardware and software and related services.
/// It is not to be confused with any other similar marks covering other goods and services.
///
/// \par Copyright
///
/// This software is Copyright (C) 2011-2016 Mike McCauley. Use is subject to license
/// conditions. The main licensing options available are GPL V2 or Commercial:
/// 
/// \par Open Source Licensing GPL V2
///
/// This is the appropriate option if you want to share the source code of your
/// application with everyone you distribute it to, and you also want to give them
/// the right to share who uses it. If you wish to use this software under Open
/// Source Licensing, you must contribute all your source code to the open source
/// community in accordance with the GPL Version 2 when your application is
/// distributed. See http://www.gnu.org/copyleft/gpl.html
/// 
/// \par Commercial Licensing
///
/// This is the appropriate option if you are creating proprietary applications
/// and you are not prepared to distribute and share the source code of your
/// application. Contact info@airspayce.com for details (do not use this address for anything other than 
/// commercial license enquiries. For all other queries, using the RadioHead mailing list).
///
/// \par Revision History
/// \version 1.1 2014-04-14<br>
///              Initial public release
/// \version 1.2 2014-04-23<br>
///              Fixed various typos. <br>
///              Added links to compatible Anarduino products.<br>
///              Added RHNRFSPIDriver, RH_NRF24 classes to support Nordic NRF24 based radios.
/// \version 1.3 2014-04-28<br>
///              Various documentation fixups.<br>
///              RHDatagram::setThisAddress() did not set the local copy of thisAddress. Reported by Steve Childress.<br>
///              Fixed a problem on Teensy with RF22 and RF69, where the interrupt pin needs to be set for input, <br>
///              else pin interrupt doesn't work properly. Reported by Steve Childress and patched by 
///              Adrien van den Bossche. Thanks.<br>
///              Fixed a problem that prevented RF22 honouring setPromiscuous(true). Reported by Steve Childress.<br>
///              Updated documentation to clarify some issues to do with maximum message lengths 
///              reported by Steve Childress.<br>
///              Added support for yield() on systems that support it (currently Arduino 1.5.5 and later)
///              so that spin-loops can suport multitasking. Suggested by Steve Childress.<br>
///              Added RH_RF22::setGpioReversed() so the reversal it can be configured at run-time after
///              radio initialisation. It must now be called _after_ init(). Suggested by Steve Childress.<br>
/// \version 1.4 2014-04-29<br>
///              Fixed further problems with Teensy compatibility for RH_RF22. Tested on Teensy 3.1.
///              The example/rf22_* examples now run out of the box with the wiring connections as documented for Teensy
///              in RH_RF22.<br>
///              Added YIELDs to spin-loops in RHRouter, RHMesh and RHReliableDatagram, RH_NRF24.<br>
///              Tested RH_Serial examples with Teensy 3.1: they now run out of the box.<br>
///              Tested RH_ASK examples with Teensy 3.1: they now run out of the box.<br>
///              Reduced default SPI speed for NRF24 from 8MHz to 1MHz on Teensy, to improve reliability when
///              poor wiring is in use.<br>
///              on some devices such as Teensy.<br>
///              Tested RH_NRF24 examples with Teensy 3.1: they now run out of the box.<br>
/// \version 1.5 2014-04-29<br>
///              Added support for Nordic Semiconductor nRF905 transceiver with RH_NRF905 driver. Also
///              added examples for nRF905 and tested on Teensy 3.1
/// \version 1.6 2014-04-30<br>
///              NRF905 examples were missing
/// \version 1.7 2014-05-03<br>
///              Added support for Arduino Due. Tested with RH_NRF905, RH_Serial, RH_ASK.
///              IMPORTANT CHANGE to interrupt pins on Arduino with RH_RF22 and RH_RF69 constructors:
///              previously, you had to specify the interrupt _number_ not the interrupt _pin_. Arduinos and Uno32
///              are now consistent with all other platforms: you must specify the interrupt pin number. Default
///              changed to pin 2 (a common choice with RF22 shields).
///              Removed examples/maple/maple_rf22_reliable_datagram_client and 
///              examples/maple/maple_rf22_reliable_datagram_client since the rf22 examples now work out
///              of the box with Flymaple.
///              Removed examples/uno32/uno32_rf22_reliable_datagram_client and 
///              examples/uno32/uno32_rf22_reliable_datagram_client since the rf22 examples now work out
///              of the box with ChipKit Uno32.
/// \version 1.8 2014-05-08 <br>
///              Added support for YIELD in Teensy 2 and 3, suggested by Steve Childress.<br>
///              Documentation updates. Clarify use of headers and Flags<br>
///              Fixed misalignment in RH_RF69 between ModemConfigChoice definitions and the implemented choices
///              which meant you didnt get the choice you thought and GFSK_Rb55555Fd50 hung the transmitter.<br>
///              Preliminary work on Linux simulator.
/// \version 1.9 2014-05-14 <br>
///              Added support for using Timer 2 instead of Timer 1 on Arduino in RH_ASK when
///              RH_ASK_ARDUINO_USE_TIMER2 is defined. With the kind assistance of
///              Luc Small. Thanks!<br>
///              Updated comments in RHReliableDatagram concerning servers, retries, timeouts and delays.
///              Fixed an error in RHReliableDatagram where recvfrom return value was not checked.
///              Reported by Steve Childress.<br>
///              Added Linux simulator support so simple RadioHead sketches can be compiled and run on Linux.<br>
///              Added RH_TCP driver to permit message passing between simulated sketches on Linux.<br>
///              Added example simulator sketches.<br>
///              Added tools/etherSimulator.pl, a simulator of the 'Luminiferous Ether' that passes
///              messages between simulated sketches and can simulate random message loss etc.<br>
///              Fixed a number of typos and improved some documentation.<br>
/// \version 1.10 2014-05-15 <br>
///              Added support for RFM73 modules to RH_NRF24. These 2 radios are very similar, and can interoperate
///              with each other. Added new RH_NRF24::TransmitPower enums for the RFM73, which has a different 
///              range of available powers<br>
///              reduced the default SPI bus speed for RH_NRF24 to 1MHz, since so many modules and CPU have problems
///              with 8MHz.<br>
/// \version 1.11 2014-05-18<br>
///              Testing RH_RF22 with RFM23BP and 3.3V Teensy 3.1 and 5V Arduinos. 
///              Updated documentation with respect to GPIO and antenna
///              control pins for RFM23. Updated documentation with respect to transmitter power control for RFM23<br>
///              Fixed a problem with RH_RF22 driver, where GPIO TX and RX pins were not configured during
///              initialisation, causing poor transmit power and sensitivity on those RF22/RF23 devices where GPIO controls
///              the antenna selection pins.
/// \version 1.12 2014-05-20<br>
///              Testing with RF69HW and the RH_RF69 driver. Works well with the Anarduino MiniWireless -CW and -HW 
///              boards http://www.anarduino.com/miniwireless/ including
///              the marvellous high powered MinWireless-HW (with 20dBm output for excellent range).<br>
///              Clarified documentation of RH_RF69::setTxPower values for different models of RF69.<br>
///              Added RHReliableDatagram::resetRetransmissions().<br>
///              Retransmission count precision increased to uin32_t.<br>
///              Added data about actual power measurements from RFM22 module.<br>
/// \version 1.13 2014-05-23<br>
///              setHeaderFlags(flags) changed to setHeaderFlags(set, clear), enabling any flags to be
///              individually set and cleared by either RadioHead or application code. Requested by Steve Childress.<br>
///              Fixed power output setting for boost power on RF69HW for 18, 19 and 20dBm.<br>
///              Added data about actual power measurements from RFM69W and RFM69HW modules.<br>
/// \version 1.14 2014-05-26<br>
///              RH_RF69::init() now always sets the PA boost back to the default settings, else can get invalid
///              PA power modes after uploading new sketches without a power cycle. Reported by Bryan.<br>
///              Added new macros RH_VERSION_MAJOR RH_VERSION_MINOR, with automatic maintenance in Makefile.<br>
///              Improvements to RH_TCP: constructor now honours the server argument in the form "servername:port".<br>
///              Added YIELD to RHReliableDatagram::recvfromAckTimeout. Requested by Steve Childress.<br>
///              Fixed a problem with RH_RF22 reliable datagram acknowledgements that was introduced in version 1.13.
///              Reported by Steve Childress.<br>
/// \version 1.15 2014-05-27<br>
///              Fixed a problem with the RadioHead .zip link.
/// \version 1.16 2014-05-30 <br>
///              Fixed RH_RF22 so that lastRssi() returns the signal strength in dBm. Suggested by Steve Childress.<br>
///              Added support for getLastPreambleTime() to RH_RF69. Requested by Steve Childress.<br>
///              RH_NRF24::init() now checks if there is a device connected and responding, else init() will fail.
///              Suggested by Steve Brown.<br>
///              RHSoftwareSPI now initialises default values for SPI pins MOSI = 12, MISO = 11 and SCK = 13.<br>
///              Fixed some problems that prevented RH_NRF24 working with mixed software and hardware SPI 
///              on different devices: a race condition
///              due to slow SPI transfers and fast acknowledgement.<br>
/// \version 1.17 2014-06-02 <br>
///              Fixed a debug typo in RHReliableDatagram that was introduced in 1.16.<br>
///              RH_NRF24 now sets default power, data rate and channel in init(), in case another
///              app has previously set different values without powerdown.<br>
///              Caution: there are still problems with RH_NRF24 and Software SPI. Do not use.<br>
/// \version 1.18 2014-06-02<br>
///              Improvements to performance of RH_NRF24 statusRead, allowing RH_NRF24 and Software SPI
///              to operate on slow devices like Arduino Uno.<br>
/// \version 1.19 2014-06-19<br>
///              Added examples ask_transmitter.pde and ask_receiver.pde.<br>
///              Fixed an error in the RH_RF22 doc for connection of Teensy to RF22.<br>
///              Improved documentation of start symbol bit patterns in RH_ASK.cpp
/// \version 1.20 2014-06-24<br>
///              Fixed a problem with compiling on platforms such as ATTiny where SS is not defined.<br>
///              Added YIELD to RHMesh::recvfromAckTimeout().<br>
/// \version 1.21 2014-06-24<br>
///              Fixed an issue in RH_Serial where characters might be lost with back-to-back frames.
///              Suggested by Steve Childress.<br>
///              Brought previous RHutil/crc16.h code into mainline RHCRC.cpp to prevent name collisions
///              with other similarly named code in other libraries. Suggested by Steve Childress.<br>
///              Fix SPI bus speed errors on 8MHz Arduinos.
/// \version 1.22 2014-07-01<br>
///              Update RH_ASK documentation for common wiring connections.<br>
///              Testing RH_ASK with HopeRF RFM83C/RFM85 courtesy Anarduino http://www.anarduino.com/<br>
///              Testing RH_NRF24 with Itead Studio IBoard Pro http://imall.iteadstudio.com/iboard-pro.html
///              using both hardware SPI on the ITDB02 Parallel LCD Module Interface pins and software SPI
///              on the nRF24L01+ Module Interface pins. Documented wiring required.<br>
///              Added support for AVR 1284 and 1284p, contributed by Peter Scargill.
///              Added support for Semtech SX1276/77/78 and HopeRF RFM95/96/97/98 and other similar LoRa capable radios
///              in LoRa mode only. Tested with the excellent MiniWirelessLoRa from 
///              Anarduino http://www.anarduino.com/miniwireless<br>
/// \version 1.23 2014-07-03<br>
///              Changed the default modulation for RH_RF69 to GFSK_Rb250Fd250, since the previous default
///              was not very reliable.<br>
///              Documented RH_RF95 range tests.<br>
///              Improvements to RH_RF22 RSSI readings so that lastRssi correctly returns the last message in dBm.<br>
/// \version 1.24 2014-07-18
///              Added support for building RadioHead for STM32F4 Discovery boards, using the native STM Firmware libraries,
///              in order to support Codec2WalkieTalkie (http://www.airspayce.com/mikem/Codec2WalkieTalkie)
///              and other projects. See STM32ArduinoCompat.<br>
///              Default modulation for RH_RF95 was incorrectly set to a very slow Bw125Cr48Sf4096
/// \version 1.25 2014-07-25
///              The available() function will longer terminate any current transmission, and force receive mode. 
///              Now, if there is no unprocessed incoming message and an outgoing message is currently being transmitted, 
///              available() will return false.<br>
///              RHRouter::sendtoWait(uint8_t*, uint8_t, uint8_t, uint8_t) renamed to sendtoFromSourceWait due to conflicts
///              with new sendtoWait() with optional flags.<br>
///              RHMEsh and RHRouter already supported end-to-end application layer flags, but RHMesh::sendtoWait() 
///              and RHRouter::sendToWait have now been extended to expose a way to send optional application layer flags.
/// \version 1.26 2014-08-12
///              Fixed a Teensy 2.0 compile problem due yield() not available on Teensy < 3.0. <br>
///              Adjusted the algorithm of RH_RF69::temperatureRead() to more closely reflect reality.<br>
///              Added functions to RHGenericDriver to get driver packet statistics: rxBad(), rxGood(), txGood().<br>
///              Added RH_RF69::printRegisters().<br>
///              RH_RF95::printRegisters() was incorrectly printing the register index instead of the address.
///              Reported by Phang Moh Lim.<br>
///              RH_RF95, added definitions for some more registers that are usable in LoRa mode.<br>
///              RH_RF95::setTxPower now uses RH_RF95_PA_DAC_ENABLE to achieve 21, 22 and 23dBm.<br>
///              RH_RF95, updated power output measurements.<br>
///              Testing RH_RF69 on Teensy 3.1 with RF69 on PJRC breakout board. OK.<br>
///              Improvements so RadioHead will build under Arduino where SPI is not supported, such as 
///              ATTiny.<br>
///              Improvements so RadioHead will build for ATTiny using Arduino IDE and tinycore arduino-tiny-0100-0018.zip.<br>
///              Testing RH_ASK on ATTiny85. Reduced RAM footprint. 
///              Added helpful documentation. Caution: RAM memory is *very* tight on this platform.<br>
///              RH_RF22 and RH_RF69, added setIdleMode() function to allow the idle mode radio operating state
///              to be controlled for lower idle power consumption at the expense of slower transitions to TX and RX.<br>
/// \version 1.27 2014-08-13
///              All RH_RF69 modulation schemes now have data whitening enabled by default.<br>
///              Tested and added a number of OOK modulation schemes to RH_RF69 Modem config table.<br>
///              Minor improvements to a number of the faster RH_RF69 modulation schemes, but some slower ones
///              are still not working correctly.<br>
/// \version 1.28 2014-08-20
///              Added new RH_RF24 driver to support Si446x, RF24/26/26, RFM24/26/27 family of transceivers.
///              Tested with the excellent
///              Anarduino Mini and RFM24W and RFM26W with the generous assistance of the good people at 
///              Anarduino http://www.anarduino.com.
/// \version 1.29 2014-08-21
///              Fixed a compile error in RH_RF24 introduced at the last minute in hte previous release.<br>
///              Improvements to RH_RF69 modulation schemes: now include the AFCBW in teh ModemConfig.<br>
///              ModemConfig RH_RF69::FSK_Rb2Fd5 and RH_RF69::GFSK_Rb2Fd5 are now working.<br> 
/// \version 1.30 2014-08-25
///              Fixed some compile problems with ATtiny84 on Arduino 1.5.5 reported by Glen Cook.<br>
/// \version 1.31 2014-08-27
///              Changed RH_RF69 FSK and GFSK modulations from Rb2_4Fd2_4 to Rb2_4Fd4_8 and FSK_Rb4_8Fd4_8 to FSK_Rb4_8Fd9_6
///              since the previous ones were unreliable (they had modulation indexes of 1).<br>
/// \version 1.32 2014-08-28
///              Testing with RedBearLab Blend board http://redbearlab.com/blend/. OK.<br>
///              Changed more RH_RF69 FSK and GFSK slowish modulations to have modulation index of 2 instead of 1. 
///              This required chnaging the symbolic names.<br>
/// \version 1.33 2014-09-01
///              Added support for sleep mode in RHGeneric driver, with new mode 
///              RHModeSleep and new virtual function sleep().<br>
///              Added support for sleep to RH_RF69, RH_RF22, RH_NRF24, RH_RF24, RH_RF95 drivers.<br>
/// \version 1.34 2014-09-19
///              Fixed compile errors in example rf22_router_test.<br>
///              Fixed a problem with RH_NRF24::setNetworkAddress, also improvements to RH_NRF24 register printing.
///              Patched by Yveaux.<br>
///              Improvements to RH_NRF24 initialisation for version 2.0 silicon.<br>
///              Fixed problem with ambigiguous print call in RH_RFM69 when compiling for Codec2.<br>
///              Fixed a problem with RH_NRF24 on RFM73 where the LNA gain was not set properly, reducing the sensitivity
///              of the receiver.
/// \version 1.35 2014-09-19
///              Fixed a problem with interrupt setup on RH_RF95 with Teensy3.1. Reported by AD.<br>
/// \version 1.36 2014-09-22
///              Improvements to interrupt pin assignments for __AVR_ATmega1284__ and__AVR_ATmega1284P__, provided by
///              Peter Scargill.<br>
///              Work around a bug in Arduino 1.0.6 where digitalPinToInterrupt is defined but NOT_AN_INTERRUPT is not.<br>
///  \version 1.37 2014-10-19
///              Updated doc for connecting RH_NRF24 to Arduino Mega.<br>
///              Changes to RHGenericDriver::setHeaderFlags(), so that the default for the clear argument
///              is now RH_FLAGS_APPLICATION_SPECIFIC, which is less surprising to users.
///              Testing with the excellent MoteinoMEGA from LowPowerLab 
///              https://lowpowerlab.com/shop/moteinomega with on-board RFM69W.
///  \version 1.38 2014-12-29
///              Fixed compile warning on some platforms where RH_RF24::send and RH_RF24::writeTxFifo 
///              did not return a value.<br>
///              Fixed some more compiler warnings in RH_RF24 on some platforms.<br>
///              Refactored printRegisters for some radios. Printing to Serial
///              is now controlled by the definition of RH_HAVE_SERIAL.<br>
///              Added partial support for ARM M4 w/CMSIS with STM's Hardware Abstraction lib for 
///              Steve Childress.<br>
///  \version 1.39 2014-12-30
///              Fix some compiler warnings under IAR.<br>
///              RH_HAVE_SERIAL and Serial.print calls removed for ATTiny platforms.<br>
///  \version 1.40 2015-03-09
///              Added notice about availability on PlatformIO, thanks to Ivan Kravets.<br>
///              Fixed a problem with RH_NRF24 where short packet lengths would occasionally not be trasmitted
///              due to a race condition with RH_NRF24_TX_DS. Reported by Mark Fox.<br>
///  \version 1.41 2015-03-29
///              RH_RF22, RH_RF24, RH_RF69 and RH_RF95 improved to allow driver.init() to be called multiple
///              times without reallocating a new interrupt, allowing the driver to be reinitialised
///              after sleeping or powering down.
///  \version 1.42 2015-05-17
///              Added support for RH_NRF24 driver on Raspberry Pi, using BCM2835
///              library for GPIO pin IO. Contributed by Mike Poublon.<br>
///              Tested RH_NRF24 module with NRF24L01+PA+LNA SMA Antenna Wireless Transceiver modules
///              similar to: http://www.elecfreaks.com/wiki/index.php?title=2.4G_Wireless_nRF24L01p_with_PA_and_LNA
///              works with no software changes. Measured max power output 18dBm.<br>
///  \version 1.43 2015-08-02
///              Added RH_NRF51 driver to support Nordic nRF51 family processor with 2.4GHz radio such 
///              as nRF51822, to be built on Arduino 1.6.4 and later. Tested with RedBearLabs nRF51822 board
///              and BLE Nano kit<br>
///  \version 1.44 2015-08-08
///              Fixed errors with compiling on some platforms without serial, such as ATTiny. 
///              Reported by Friedrich Müller.<br>
///  \version 1.45 2015-08-13
///              Added support for using RH_Serial on Linux and OSX (new class RHutil/HardwareSerial
///              encapsulates serial ports on those platforms). Example examples/serial upgraded
///              to build and run on Linux and OSX using the tools/simBuild builder.
///              RHMesh, RHRouter and RHReliableDatagram updated so they can use RH_Serial without
///              polling loops on Linux and OSX for CPU efficiency.<br>
///  \version 1.46 2015-08-14
///              Amplified some doc concerning Linux and OSX RH_Serial. Added support for 230400
///              baud rate in HardwareSerial.<br>
///              Added sample sketches nrf51_audio_tx and nrf51_audio_rx which show how to
///              build an audio TX/RX pair with RedBear nRF51822 boards and a SparkFun MCP4725 DAC board.
///              Uses the built-in ADC of the nRF51822 to sample audio at 5kHz and transmit packets
///              to the receiver which plays them via the DAC.<br>
/// \version 1.47 2015-09-18
///              Removed top level Makefile from distribution: its only used by the developer and 
///              its presence confuses some people.<br>
///              Fixed a problem with RHReliableDatagram with some versions of Raspberry Pi random() that causes 
///              problems: random(min, max) sometimes exceeds its max limit.
/// \version 1.48 2015-09-30
///              Added support for Arduino Zero. Tested on Arduino Zero Pro.
/// \version 1.49 2015-10-01
///              Fixed problems that prevented interrupts working correctly on Arduino Zero and Due.
///              Builds and runs with 1.6.5 (with 'Arduino SAMD Boards' for Zero version 1.6.1) from arduino.cc.
///              Arduino version 1.7.7 from arduino.org is not currently supported.
/// \version 1.50 2015-10-25
///              Verified correct building and operation with Arduino 1.7.7 from arduino.org.
///              Caution: You must burn the bootloader from 1.7.7 to the Arduino Zero before it will 
///              work with Arduino 1.7.7 from arduino.org. Conversely, you must burn the bootloader from 1.6.5 
///              to the Arduino Zero before it will 
///              work with Arduino 1.6.5 from arduino.cc. Sigh.
///              Fixed a problem with RH_NRF905 that prevented the power and frequency ranges being set
///              properly. Reported by Alan Webber.
/// \version 1.51 2015-12-11
///              Changes to RH_RF6::setTxPower() to be compatible with SX1276/77/78/79 modules that
///              use RFO transmitter pins instead of PA_BOOST, such as the excellent
///              Modtronix inAir4 http://modtronix.com/inair4.html 
///              and inAir9 modules http://modtronix.com/inair9.html. With the kind assistance of 
///              David from Modtronix.
/// \version 1.52 2015-12-17
///              Added RH_MRF89 module to suport Microchip MRF89XA and compatible transceivers.
///              and modules.<br>
/// \version 1.53 2016-01-02
///              Added RH_CC110 module to support Texas Instruments CC110L and compatible transceivers and modules.<br>
/// \version 1.54 2016-01-29
///              Added support for ESP8266 processor on Arduino IDE. Examples serial_reliable_datagram_* are shown to work. 
///              CAUTION: SPI not supported yet. Timers used by RH_ASK are not tested. 
///              The GHz radio included in the ESP8266 is not yet supported. 
/// \version 1.55 2016-02-12
///              Added macros for htons() and friends to RadioHead.h.
///              Added example sketch serial_gateway.pde. Acts as a transparent gateway between RH_RF22 and RH_Serial, 
///              and with minor mods acts as a universal gateway between any 2 RadioHead driver networks.
///              Initial work on supporting STM32 F2 on Particle Photon: new platform type defined.
///              Fixed many warnings exposed by test building for Photon.
///              Particle Photon tested support for RH_Serial, RH_ASK, SPI, RH_CC110 etc.
///              Added notes on how to build RadioHead sketches for Photon.
/// \version 1.56 2016-02-18 
///              Implemented timers for RH_ASK on ESP8266, added some doc on IO pin selection.
/// \version 1.57 2016-02-23
///              Fixed an issue reported by S3B, where RH_RF22 would sometimes not clear the rxbufvalid flag.
///
/// \author  Mike McCauley. DO NOT CONTACT THE AUTHOR DIRECTLY. USE THE MAILING LIST GIVEN ABOVE

#ifndef RadioHead_h
#define RadioHead_h

// Official version numbers are maintained automatically by Makefile:
#define RH_VERSION_MAJOR 1
#define RH_VERSION_MINOR 57

// Symbolic names for currently supported platform types
#define RH_PLATFORM_ARDUINO          1
#define RH_PLATFORM_MSP430           2
#define RH_PLATFORM_STM32            3
#define RH_PLATFORM_GENERIC_AVR8     4
#define RH_PLATFORM_UNO32            5
#define RH_PLATFORM_UNIX             6
#define RH_PLATFORM_STM32STD         7
#define RH_PLATFORM_STM32F4_HAL      8 
#define RH_PLATFORM_RASPI            9
#define RH_PLATFORM_NRF51            10
#define RH_PLATFORM_ESP8266          11
#define RH_PLATFORM_STM32F2          12

////////////////////////////////////////////////////
// Select platform automatically, if possible
#ifndef RH_PLATFORM
 #if defined(MPIDE)
  #define RH_PLATFORM RH_PLATFORM_UNO32
 #elif defined(NRF51)
  #define RH_PLATFORM RH_PLATFORM_NRF51
 #elif defined(ESP8266)
  #define RH_PLATFORM RH_PLATFORM_ESP8266
 #elif defined(ARDUINO)
  #define RH_PLATFORM RH_PLATFORM_ARDUINO
 #elif defined(__MSP430G2452__) || defined(__MSP430G2553__)
  #define RH_PLATFORM RH_PLATFORM_MSP430
 #elif defined(MCU_STM32F103RE)
  #define RH_PLATFORM RH_PLATFORM_STM32
 #elif defined(STM32F2XX)
  #define RH_PLATFORM RH_PLATFORM_STM32F2
 #elif defined(USE_STDPERIPH_DRIVER)
  #define RH_PLATFORM RH_PLATFORM_STM32STD
 #elif defined(RASPBERRY_PI)
  #define RH_PLATFORM RH_PLATFORM_RASPI
#elif defined(__unix__) // Linux
  #define RH_PLATFORM RH_PLATFORM_UNIX
#elif defined(__APPLE__) // OSX
  #define RH_PLATFORM RH_PLATFORM_UNIX
 #else
  #error Platform not defined! 	
 #endif
#endif

#if defined(__AVR_ATtiny84__) || defined(__AVR_ATtiny85__) || defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtinyX4__) || defined(__AVR_ATtinyX5__) || defined(__AVR_ATtiny2313__) || defined(__AVR_ATtiny4313__) || defined(__AVR_ATtinyX313__)
 #define RH_PLATFORM_ATTINY
#endif

////////////////////////////////////////////////////
// Platform specific headers:
#if (RH_PLATFORM == RH_PLATFORM_ARDUINO)
 #if (ARDUINO >= 100)
  #include <Arduino.h>
 #else
  #include <wiring.h>
 #endif
 #ifdef RH_PLATFORM_ATTINY
  #warning Arduino TinyCore does not support hardware SPI. Use software SPI instead.
 #else
  #include <SPI.h>
  #define RH_HAVE_HARDWARE_SPI
  #define RH_HAVE_SERIAL
 #endif

#elif (RH_PLATFORM == RH_PLATFORM_ESP8266) // ESP8266 processor on Arduino IDE
 #include <Arduino.h>
 #include <SPI.h>
 #define RH_HAVE_HARDWARE_SPI
 #define RH_HAVE_SERIAL
#elif (RH_PLATFORM == RH_PLATFORM_MSP430) // LaunchPad specific
 #include "legacymsp430.h"
 #include "Energia.h"
 #include <SPI.h>
 #define RH_HAVE_HARDWARE_SPI
 #define RH_HAVE_SERIAL

#elif (RH_PLATFORM == RH_PLATFORM_UNO32)
 #include <WProgram.h>
 #include <string.h>
 #include <SPI.h>
 #define RH_HAVE_HARDWARE_SPI
 #define memcpy_P memcpy
 #define RH_HAVE_SERIAL

#elif (RH_PLATFORM == RH_PLATFORM_STM32) // Maple, Flymaple etc
 #include <wirish.h>	
 #include <stdint.h>
 #include <string.h>
 #include <HardwareSPI.h>
 #define RH_HAVE_HARDWARE_SPI
 // Defines which timer to use on Maple
 #define MAPLE_TIMER 1
 #define PROGMEM
 #define memcpy_P memcpy
 #define Serial SerialUSB
 #define RH_HAVE_SERIAL

#elif (RH_PLATFORM == RH_PLATFORM_STM32F2) // Particle Photon with firmware-develop
 #include <stm32f2xx.h>
 #include <application.h>
 #include <math.h> // floor
 #define RH_HAVE_SERIAL
 #define RH_HAVE_HARDWARE_SPI

#elif (RH_PLATFORM == RH_PLATFORM_STM32STD) // STM32 with STM32F4xx_StdPeriph_Driver 
 #include <stm32f4xx.h>
 #include <wirish.h>	
 #include <stdint.h>
 #include <string.h>
 #include <math.h>
 #include <HardwareSPI.h>
 #define RH_HAVE_HARDWARE_SPI
 #define Serial SerialUSB
 #define RH_HAVE_SERIAL

#elif (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8) 
 #include <avr/io.h>
 #include <avr/interrupt.h>
 #include <util/delay.h>
 #include <string.h>
 #include <stdbool.h>
 #define RH_HAVE_HARDWARE_SPI
 #include <SPI.h>

// For Steve Childress port to ARM M4 w/CMSIS with STM's Hardware Abstraction lib. 
// See ArduinoWorkarounds.h (not supplied)
#elif (RH_PLATFORM == RH_PLATFORM_STM32F4_HAL) 
 #include <ArduinoWorkarounds.h>
 #include <stm32f4xx.h> // Also using ST's CubeMX to generate I/O and CPU setup source code for IAR/EWARM, not GCC ARM.
 #include <stdint.h>
 #include <string.h>
 #include <math.h>
 #define RH_HAVE_HARDWARE_SPI // using HAL (Hardware Abstraction Libraries from ST along with CMSIS, not arduino libs or pins concept.

#elif (RH_PLATFORM == RH_PLATFORM_RASPI)
 #define RH_HAVE_HARDWARE_SPI
 #define RH_HAVE_SERIAL
 #define PROGMEM
 #include <RHutil/RasPi.h>
 #include <string.h>
 //Define SS for CS0 or pin 24
 #define SS 8

#elif (RH_PLATFORM == RH_PLATFORM_NRF51)
 #define RH_HAVE_SERIAL
 #define PROGMEM
  #include <Arduino.h>

#elif (RH_PLATFORM == RH_PLATFORM_UNIX) 
 // Simulate the sketch on Linux and OSX
 #include <RHutil/simulator.h>
 #define RH_HAVE_SERIAL
#include <netinet/in.h> // For htons and friends

#else
 #error Platform unknown!
#endif

////////////////////////////////////////////////////
// This is an attempt to make a portable atomic block
#if (RH_PLATFORM == RH_PLATFORM_ARDUINO)
#if defined(__arm__)
  #include <RHutil/atomic.h>
 #else
  #include <util/atomic.h>
 #endif
 #define ATOMIC_BLOCK_START     ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
 #define ATOMIC_BLOCK_END }
#elif (RH_PLATFORM == RH_PLATFORM_UNO32)
 #include <peripheral/int.h>
 #define ATOMIC_BLOCK_START unsigned int __status = INTDisableInterrupts(); {
 #define ATOMIC_BLOCK_END } INTRestoreInterrupts(__status);
#elif (RH_PLATFORM == RH_PLATFORM_STM32F2) // Particle Photon with firmware-develop
 #define ATOMIC_BLOCK_START { int __prev = HAL_disable_irq();
 #define ATOMIC_BLOCK_END  HAL_enable_irq(__prev); }
#elif (RH_PLATFORM == RH_PLATFORM_ESP8266)
// See hardware/esp8266/2.0.0/cores/esp8266/Arduino.h
 #define ATOMIC_BLOCK_START { uint32_t __savedPS = xt_rsil(15);
 #define ATOMIC_BLOCK_END xt_wsr_ps(__savedPS);}
#else 
 // TO BE DONE:
 #define ATOMIC_BLOCK_START
 #define ATOMIC_BLOCK_END
#endif

////////////////////////////////////////////////////
// Try to be compatible with systems that support yield() and multitasking
// instead of spin-loops
// Recent Arduino IDE or Teensy 3 has yield()
#if (RH_PLATFORM == RH_PLATFORM_ARDUINO && ARDUINO >= 155 && !defined(RH_PLATFORM_ATTINY)) || (TEENSYDUINO && defined(__MK20DX128__))
 #define YIELD yield();
#elif (RH_PLATFORM == RH_PLATFORM_ESP8266)
// ESP8266 also hash it
 #define YIELD yield();
#else
 #define YIELD
#endif

////////////////////////////////////////////////////
// digitalPinToInterrupt is not available prior to Arduino 1.5.6 and 1.0.6
// See http://arduino.cc/en/Reference/attachInterrupt
#ifndef NOT_AN_INTERRUPT
 #define NOT_AN_INTERRUPT -1
#endif
#ifndef digitalPinToInterrupt
 #if (RH_PLATFORM == RH_PLATFORM_ARDUINO) && !defined(__arm__)

  #if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
   // Arduino Mega, Mega ADK, Mega Pro
   // 2->0, 3->1, 21->2, 20->3, 19->4, 18->5
   #define digitalPinToInterrupt(p) ((p) == 2 ? 0 : ((p) == 3 ? 1 : ((p) >= 18 && (p) <= 21 ? 23 - (p) : NOT_AN_INTERRUPT)))

  #elif defined(__AVR_ATmega1284__) || defined(__AVR_ATmega1284P__) 
   // Arduino 1284 and 1284P - See Manicbug and Optiboot
   // 10->0, 11->1, 2->2
   #define digitalPinToInterrupt(p) ((p) == 10 ? 0 : ((p) == 11 ? 1 : ((p) == 2 ? 2 : NOT_AN_INTERRUPT)))

  #elif defined(__AVR_ATmega32U4__)
   // Leonardo, Yun, Micro, Pro Micro, Flora, Esplora
   // 3->0, 2->1, 0->2, 1->3, 7->4
   #define digitalPinToInterrupt(p) ((p) == 0 ? 2 : ((p) == 1 ? 3 : ((p) == 2 ? 1 : ((p) == 3 ? 0 : ((p) == 7 ? 4 : NOT_AN_INTERRUPT)))))

  #else
   // All other arduino except Due:
   // Serial Arduino, Extreme, NG, BT, Uno, Diecimila, Duemilanove, Nano, Menta, Pro, Mini 04, Fio, LilyPad, Ethernet etc
   // 2->0, 3->1
   #define digitalPinToInterrupt(p)  ((p) == 2 ? 0 : ((p) == 3 ? 1 : NOT_AN_INTERRUPT))

  #endif
 
 #elif (RH_PLATFORM == RH_PLATFORM_UNO32)
  #define digitalPinToInterrupt(p) ((p) == 38 ? 0 : ((p) == 2 ? 1 : ((p) == 7 ? 2 : ((p) == 8 ? 3 : ((p) == 735 ? 4 : NOT_AN_INTERRUPT)))))

 #else
  // Everything else (including Due and Teensy) interrupt number the same as the interrupt pin number
  #define digitalPinToInterrupt(p) (p)
 #endif
#endif

// On some platforms, attachInterrupt() takes a pin number, not an interrupt number
#if (RH_PLATFORM == RH_PLATFORM_ARDUINO) && defined (__arm__) && (defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_SAM_DUE))
 #define RH_ATTACHINTERRUPT_TAKES_PIN_NUMBER
#endif

// Slave select pin, some platforms such as ATTiny do not define it.
#ifndef SS
 #define SS 10
#endif

// These defs cause trouble on some versions of Arduino
#undef abs
#undef round
#undef double

// Sigh: there is no widespread adoption of htons and friends in the base code, only in some WiFi headers etc
// that have a lot of excess baggage
#if RH_PLATFORM != RH_PLATFORM_UNIX && !defined(htons)
// #ifndef htons
// These predefined macros availble on modern GCC compilers
 #if   __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
  // Atmel processors
  #define htons(x) ( ((x)<<8) | (((x)>>8)&0xFF) )
  #define ntohs(x) htons(x)
  #define htonl(x) ( ((x)<<24 & 0xFF000000UL) | \
                   ((x)<< 8 & 0x00FF0000UL) | \
                   ((x)>> 8 & 0x0000FF00UL) | \
                   ((x)>>24 & 0x000000FFUL) )
  #define ntohl(x) htonl(x)

 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
  // Others
  #define htons(x) (x)
  #define ntohs(x) (x)
  #define htonl(x) (x)
  #define ntohl(x) (x)

 #else
  #error "Dont know how to define htons and friends for this processor" 
 #endif
#endif

// This is the address that indicates a broadcast
#define RH_BROADCAST_ADDRESS 0xff

#endif