Digi XBee ANSI C Library

The project is a collection of portable ANSI C code for communicating with Digi International's XBee wireless radio modules in API mode. You will typically compile/link the files directly into your application, instead of compiling them into a shared/dynamic-link library. Because of this design, most of the library configuration takes place at compile time.

This source has been contributed by Digi International under the Mozilla Public License v2.0. It is a BETA quality software release, and has gone through a limited QA cycle.

It currently supports the following platforms:

• POSIX operating systems (Windows with Cygwin or MSYS2, Mac OS X, Linux, BSD) with gcc
• Windows with MinGW or Mingw-w64 and gcc
• Digi International embedded hardware platforms that use libdigiapix to control GPIO pins
• DOS using the OpenWatcom compiler
• Rabbit-brand microprocessors (using Dynamic C 10.70 or later)
• Freescale HCS08 with CodeWarrior 10.x (part of Programmable XBee Dev Kit)
• Freescale FRDM-KL25Z with mbed.org compiler (limited support at this time)
• Silicon Labs SLSTK3701A Starter Kit with Gecko SDK Suite v1.1.1 or later with optional Micrium OS support

It provides an API for a host platform that communicates with an XBee radio serially. Some of the features include:

• Frame dispatcher that passes complete frames from the XBee radio out to multiple functions based on frame type.
• Interface for sending API frames serially, with automatic header and checksum.
• Message delivery that includes addressing information (short/long remote address, source/destination endpoint, cluster ID and profile ID).
• Respond to messages using addressing information from the envelope of a received message.
• Interface for sending "AT Command" frames.
• Perform Node Discovery and manage a list of nodes.
• Install firmware images (.EBL/.GBL or .OEM files) on the XBee radio.
• Parse and display digital/analog I/O samples.
• Interface with the General Purpose Memory (GPM) found on some XBee modules.

Use GitHub to report bugs, request features or contribute code to this project. Please read through this document before getting started with the code.

Requirements

Look at the README.md file in the appropriate ports/ sub-directory for information on setting up the build environment.

Documentation

You can find official documentation on the GitHub page for the project. To generate local documentation to the doc/html directory, first download and install Doxygen.

Launch Doxywizard and open Doxyfile at the root directory of the driver. Go to the "Run" tab and click the "Run doxygen" button to build the HTML documentation files. The doxygen output will produce warnings for undocumented portions of the code – that's OK and expected.

To view the documentation, open doc/html/index.html in a web browser.

XBee Firmware

Configure your XBee radio with DigiMesh, ZigBee or Smart Energy firmware in "API" mode (with an API mode firmware or by setting ATAP=1). The samples use a default baud rate of 115200. The library is written to make use of flow control, so ATD6/ATD7 needs to be set to 1. Configure the radio with ATAO set to 1 to use extended transmit and receive frames.

ZigBee Firmware

When using ZigBee and Smart Energy firmware, keep the radio set to ATAO=1. In your application, you will need to set AO to 3 at startup in order to receive and process ZDO/ZDP requests used to discover your device's endpoints and clusters. On exit, set AO back to 1 so the radio will process those requests (and Smart Energy devices can complete Key Establishment to join a network).

xbee_cmd_simple(&my_xbee, "AO", 3);

On ZigBee networks without Key Establishment, it should be safe to keep AO set to 3.

File Descriptions

Note that frame_types.md identifies headers and source files written to support each frame type.

Headers:

• xbee/platform.h: Function prototypes for hardware abstraction layer.
• ports/<target>/platform_config.h: Additional headers, automatically included by xbee/platform.h, based on the target device.
• xbee/serial.h: Platform-specific functions for managing the serial interface, reading and writing bytes, checking the XBee's CTS pin and setting the host's RTS pin.
• xbee/device.h: Read frames from XBee module and dispatch to frame handlers, send full frames to XBee module.
• xbee/atcmd.h: Working with local and remote "AT Command" frames for getting and setting XBee attributes and executing XBee commands.
• xbee/atmode.h: Interfacing with XBee module in "AT mode", currently used for firmware updates on non-ZigBee modules.
• xbee/bl_gen3.h: Support for the "Gen3 Bootloader" used by S3B, S6, S6B, XLR, Cellular, SX, SX868, and S8 hardware.
• xbee/byteorder.h: Byte-order-related functions used by multiple layers of the driver.
• xbee/cbuf.h: Circular buffer used by the serial driver on some platforms, and the "transparent serial" cluster used in OTA updates. Available for general use to upper layers of the stack.
• xbee/commissioning.h: Code for supporting the ZCL Commissioning Cluster on XBee ZB modules. See zigbee/zcl_commissioning.h for the required networking code.
• xbee/delivery_status.h: Status codes for 0x89 and 0x8B frames.
• xbee/discovery.h: Code related to Node Discovery (ATND).
• xbee/firmware.h: Code for updating radio firmware via .ebl, .gbl or .oem files.
• xbee/gpm.h: Code related to the General Purpose Memory (GPM) present on various XBee modules (e.g., S3B, S6B).
• xbee/io.h: Code for working with the analog and digital I/O pins on the XBee module.
• xbee/ipv4.h: Support for IPv4 frames on XBee and XBee3 Cellular products.
• xbee/jslong.h and xbee/jslong_glue.h: Code from mozilla.org used to manage 64-bit integers on platforms without direct support of them.
• xbee/pxbee_ota_client.h: Client code for sending OTA (over-the-air) firmware updates to Programmable XBee modules.
• xbee/pxbee_ota_server.h: Server code for advertising OTA capabilities on a device (typically a Programmable XBee module).
• xbee/scan.h: Structures describing ATAS (Active Scan) responses.
• xbee/sms.h: Support for SMS features of XBee and XBee3 Cellular products.
• xbee/socket.h and xbee/socket_frames.h: Support for Sockets API frames on XBee and XBee3 Cellular prodcuts.
• xbee/sxa.h: A "Simplified XBee API" with support for node table management, configurable I/O, point-to-point data streams and a connectionless datagram protocol. Used for XBee-only (not general ZigBee) networks. (Sample code limited to Rabbit platform.)
• xbee/time.h: Portable time functions for embedded platforms lacking full support of the Standard C Library time.h. Includes a version of gmtime() and mktime() using 1/1/2000 as the epoch.
• xbee/transparent_serial.h: Support code for the "Digi Transparent Serial" cluster (cluster 0x0011 of endpoint 0xE8), to communicate with "dumb" XBee modules running non-API mode firmware.
• xbee/user_data.h: Support for User Data Relay API frames used on XBee and XBee3 Cellular/802.15.4/Digimesh/Zigbee products.
• xbee/wifi.h: Code specific to the XBee S6B (Wi-Fi) module.
• xbee/wpan.h: Glue layer between XBee device driver and 802.15.4/ZigBee network.
• xbee/xmodem.h: XMODEM protocol layer, on top of xbee/serial layer, for sending firmware updates.
• xbee/xmodem_crc16.h: Function to calculate 16-bit XMODEM CRC.
• wpan/types.h: Types used by Wireless Personal Area Networks, not specific to the ZigBee protocol (e.g., 802.15.4 and DigiMesh).
• wpan/aps.h: APS-layer of WPAN networks (endpoints/clusters).
• zigbee/zcl.h: ZigBee Cluster Library, including general commands.
• zigbee/zcl_basic.h: Basic Cluster for ZCL.
• zigbee/zcl_basic_attributes.h: Used in main program to create a data structure and attribute for use in the device's endpoint table.
• zigbee/zcl_client.h: Helper functions for creating ZCL client clusters.
• zigbee/zcl_commissioning.h: Non-certified implementation of Commissioning Cluster (server).
• zigbee/zcl_identify.h: ZCL Identify Cluster (server).
• zigbee/zcl_onoff.h: ZCL OnOff Cluster (incomplete).
• zigbee/zcl_time.h: ZCL Time Cluster (client and server).
• zigbee/zcl_types.h: ZCL datatypes
• zigbee/zdo.h: ZigBee Device Objects/ZigBee Device Profile layer.

Source (.c) directories:

• wpan: source files for include/wpan/*.h
• xbee: source files for include/xbee/*.h
• util: Helper functions that may not be available on a given target. In some cases (like swapbytes.c), it can be used until an optimized, assembly-only version of the function can be written for the target.
• zigbee: source files for include/zigbee/*.h

Sample Programs

See samples/README.md for descriptions.

Adding to the Library

We welcome your contributions to this library of code, but ask that you please follow these general guidelines.

Coding Style

• In general, code additions should match the style of existing code. Old files used 3-space tabs to match a legacy codebase, but current preference is to use four spaces for indentation instead of tabs.
• When naming things in the global namespace (functions, macros, global variables) use a consistent prefix in the names.
• Limit line length to 80 characters.
• Use Doxygen-formatted comments for functions, types, globals and macros.
• Always use curly braces ({ and }) after if and else statements. Follow style of existing files:

  // Legacy style:
  if (foo)
  {
     do_bar();
  }
  else
  {
     do_baz();
  }
  
  // Preferred style for new code:
  if (foo) {
      do_bar();
  } else {
      do_baz();
  }
  

• Declare pointers as char *foo, not char* foo or char * foo.

Portability

This driver has been designed for portability to multiple platforms, from a resource-constrained 8-bit Freescale, up to a Windows PC. As such, it's important to keep the following in mind while working with the driver:

• Leave BeginHeader/EndHeader comments in place – they're used by the linker in Dynamic C on the Rabbit platform.

• Use ANSI C (C89/C90 preferred, C99 features allowed if widely supported). To ease portability, code should not make use of GNU or other compiler extensions.

  Exceptions: Some pointers in the driver are labelled FAR to allow for use of far memory on the Rabbit and HCS08 targets. Most target platforms define FAR as an empty macro.

• Use types from stdint.h instead of int, short and long. Unless a variable is used within a function for a loop (where int is fine), or used in a platform-specific file (e.g., as part of the hardware abstraction layer), you should make use of the standard types from stdint.h: int8_t, uint8_t, int16_t, uint16_t, int32_t, uint32_t.

• Variables and struct members that are stored in non-host-byte-order should have _le or _be appended to their names (for big endian and little endian). Use the functions from xbee/byteorder.h (htobe16, le32toh, memcpy_htobe, memcpy_betole, etc.) to convert between host and big/little endian byte order. If you pretend that you don't know your host platform's endian-ness, you'll be forced to write portable code that never assumes a given byte order.

  DO NOT use hton, ntoh, htons, ntohs, intel or intel16.

  XBee frames store multi-byte values in big endian byte order. ZigBee frames store multi-byte values in little endian byte order. Target platforms can be big endian or little endian.

  Use #if BYTE_ORDER == LITTLE_ENDIAN or #if BYTE_ORDER == BIG_ENDIAN when code requires different execution paths depending on the target's byte order.

• When working with ZCL attributes, make use of the ZCL types for 40-bit zcl40_t, 48-bit zcl48_t, and 64-bit zcl64_t values. 24-bit attributes should use uint32_t or int32_t and 56-bit attributes should use zcl64_t (ZCL automatically sign extends into the high byte).
• Place code at the correct layer of the driver. We're trying to keep the ZigBee layers (and above) separate from the XBee layers to allow for possible gateway applications (ZigBee to Ethernet, for example), and to limit the public release of ZigBee and Smart Energy code.

Other Options

If you find that this library doesn't meet your needs, take a look at libxbee, "a C/C++ library to aid the use of Digi XBee radios in API mode".

For a detailed list of libraries in many languages, visit Digi's XBee Examples site.

License

This software is open-source software. Copyright Digi International, 2013.

This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

This software includes MPL 1.1 licensed code from the Mozilla project. See include/jslong.h and src/util/jslong.c for details.