Library to easily communicate with XBee modules.

Dependencies:   DigiLogger

Dependents:   WaterLogger XbeeGateway XBee_Cooker ProjetReceiver ... more

Use XBee radio modules to easily improve your project with wireless connectivity. You can enable entire networks of connected devices. XBees can exchange data with other modules in the network and configure remote modules as well as trigger actions or collect sensor data on XBee nodes without needing additional external microcontrollers. Using this documentation and configuration tools with XBee modules, it is easy to develop these types of applications and more.

/media/uploads/spastor/xbee-xbeepro-series1.jpg

The XBee mbed Library is a ready-to-import mbed extension that dramatically reduces development time for XBee projects on the mbed platforms. There are many modular examples, making it an easy and smooth process to add wireless networking to a whole range of useful applications.

Info

Currently 802.15.4 (Series 1 and 2), ZigBee (Series 2) and DigiMesh (Series 1 and 2) modules are supported. The libraries can be extended to support other protocols like DigiMesh point-to-point, WiFi, etc.

User manual

The user manual can be found at this project's Wiki pages:

  1. Configuring the library
  2. Debugging the library
  3. Initializing modules
  4. Resetting the local module
  5. Receiving Data from other module
  6. Sending data to another module
  7. Discovering nodes in the network
  8. Configuring local and remote modules
  9. Handling modem status changes
  10. Handling remote modules DIOs, ADCs and PWMs
  11. Handling IO Data Samples from other module
  12. Radio Power Management

Ready to use examples

There are a lot of ready to use examples to get started quickly.
Make sure you have a valid example setup before running the examples:

Examples for ZigBee modules

Import programXBeeZB_Receive_Data

ZigBee Receive Data example for mbed XBeeLib By Digi

Import programXBeeZB_Send_Data

ZigBee Send Data example for mbed XBeeLib By Digi

Import programXBeeZB_module_config

ZigBee network configuration example for mbed XBeeLib By Digi

Import programXBeeZB_AT_Commands

ZigBee AT Commands example for mbed XBeeLib By Digi

Import programXBeeZB_dio_adc

ZigBee DIOs and ADCs example for mbed XBeeLib By Digi

Import programXBeeZB_IO_Sample_Callback

ZigBee IO Sampling Callback example for mbed XBeeLib By Digi

Import programXBeeZB_modem_status

ZigBee Modem Status example for mbed XBeeLib By Digi

Import programXBeeZB_node_discovery

ZigBee Node Discovery example for mbed XBeeLib By Digi

Import programXBeeZB_power_mngmnt_cyclic_sleep

ZigBee Power Management using Cyclic Sleep example for mbed XBeeLib By Digi

Import programXBeeZB_power_mngmnt_pin_sleep

ZigBee Power Management using Pin Sleep example for mbed XBeeLib By Digi

Examples for 802.15.4 modules

Import programXBee802_Receive_Data

802.15.4 Receive Data example for mbed XBeeLib By Digi

Import programXBee802_Send_Data

802.15.4 Send Data example for mbed XBeeLib By Digi

Import programXBee802_module_config

802.15.4 network configuration example for mbed XBeeLib By Digi

Import programXBee802_AT_Commands

802.15.4 AT Commands example for mbed XBeeLib By Digi

Import programXBee802_dio_adc_pwm

802.15.4 DIOs, ADCs and PWM example for mbed XBeeLib By Digi

Import programXBee802_IO_Sample_Callback

802.15.4 IO Sampling Callback example for mbed XBeeLib By Digi

Import programXBee802_node_discovery

802.15.4 Node Discovery example for mbed XBeeLib By Digi

Import programXBee802_power_mngmnt_cyclic_sleep

802.15.4 Power Management using Cyclic Sleep example for mbed XBeeLib By Digi

Import programXBee802_power_mngmnt_pin_sleep

802.15.4 Power Management using Pin Sleep example for mbed XBeeLib By Digi

Examples for DigiMesh modules

Import programXBeeDM_Receive_Data

DigiMesh Receive Data example for mbed XBeeLib By Digi

Import programXBeeDM_Send_Data

DigiMesh Send Data example for mbed XBeeLib By Digi

Import programXBeeDM_module_config

DigiMesh network configuration example for mbed XBeeLib By Digi

Import programXBeeDM_AT_Commands

DigiMesh AT Commands example for mbed XBeeLib By Digi

Import programXBeeDM_dio_adc_pwm

DigiMEsh DIOs, ADCs and PWMs example for mbed XBeeLib By Digi

Import programXBeeDM_IO_Sample_Callback

DigiMesh IO Sampling Callback example for mbed XBeeLib By Digi

Import programXBeeDM_modem_status

DigiMesh Modem Status example for mbed XBeeLib By Digi

Import programXBeeDM_node_discovery

DigiMesh Node Discovery example for mbed XBeeLib By Digi

Import programXBeeDM_power_mngmnt_asyncr_cyclic_sleep

DigiMesh Power Management using Asynchronous Cyclic Sleep example for mbed XBeeLib By Digi

Import programXBeeDM_power_mngmnt_pin_sleep

DigiMesh Power Management using Pin Sleep example for mbed XBeeLib By Digi

XBee/XBee.cpp

Committer:
hbujanda
Date:
2016-07-29
Revision:
9:780db84ce891
Parent:
6:06522f3a6642

File content as of revision 9:780db84ce891:

/**
 * Copyright (c) 2015 Digi International Inc.,
 * All rights not expressly granted are reserved.
 *
 * 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/.
 *
 * Digi International Inc. 11001 Bren Road East, Minnetonka, MN 55343
 * =======================================================================
 */

#include "XBeeLib.h"
#include "FrameHandlers/FH_ModemStatus.h"

/* States for the state machine that processes incoming data on the serial port */
#define WAITING_FOR_START_FRAME (0)
#define WAITING_FOR_LENGTH_MSB  (1)
#define WAITING_FOR_LENGTH_LSB  (2)
#define WAITING_FOR_PAYLOAD     (3)
#define WAITING_FOR_CHECKSUM    (4)

#define IS_API2()               (_mode == ModeAPI2)
#define IS_API_MODE()           (_mode == ModeAPI1 || _mode == ModeAPI2)

using namespace XBeeLib;

#if defined(FRAME_BUFFER_SIZE_SYNCR)
#if FRAME_BUFFER_SIZE_SYNCR < 2
#error "FRAME_BUFFER_SIZE_SYNCR must be at least 2"
#endif
#else
#define FRAME_BUFFER_SIZE_SYNCR     1
#endif

#define MAX_FRAME_PAYLOAD_LEN_SYNCR (1  /* type */         + 1  /* id */       + 2 /* at cmd*/    + 1 /* status */    + 2 /* MY sender */ + \
                                     8  /* 64b sender */   + 20 /* max id */   + 1 /* null ter */ + 2 /* MY parent */ + 1  /* dev type */ + \
                                     1  /* source event */ + 2  /* prof. id */ + 2 /* man. id */)

FrameBuffer XBee::_framebuf_app(FRAME_BUFFER_SIZE, MAX_FRAME_PAYLOAD_LEN);
FrameBuffer XBee::_framebuf_syncr(FRAME_BUFFER_SIZE_SYNCR, MAX_FRAME_PAYLOAD_LEN_SYNCR);

#if defined(DEVICE_SERIAL_FC)
bool XBee::check_radio_flow_control()
{
    AtCmdFrame::AtCmdResp cmdresp;
    uint32_t value;

    if (_serial_flow_type == SerialBase::RTSCTS || _serial_flow_type == SerialBase::CTS) {
        cmdresp = get_param("D7", &value);
        if (cmdresp != AtCmdFrame::AtCmdRespOk) {
            digi_log(LogLevelError, "Could not read CTS configuration. Error %d\r\n", cmdresp);
            return false;
        } else if (value != 1) {
            digi_log(LogLevelError, "Bad CTS configuration. Radio 'D7' param is %d and should be 1\r\n", value);
            return false;
        }
    }

    if (_serial_flow_type == SerialBase::RTSCTS || _serial_flow_type == SerialBase::RTS) {
        cmdresp = get_param("D6", &value);
        if (cmdresp != AtCmdFrame::AtCmdRespOk) {
            digi_log(LogLevelError, "Could not read RTS configuration. Error %d\r\n", cmdresp);
            return false;
        } else if (value != 1) {
            digi_log(LogLevelError, "Bad RTS configuration. Radio 'D6' param is %d and should be 1\r\n", value);
            return false;
        }
    }

    return true;
}
#endif

/* Class constructor */
XBee::XBee(PinName tx, PinName rx, PinName reset, PinName rts, PinName cts, int baud) :
    _mode(ModeUnknown), _hw_version(0), _fw_version(0), _timeout_ms(SYNC_OPS_TIMEOUT_MS), _dev_addr64(ADDR64_UNASSIGNED),
    _reset(NULL), _tx_options(0), _hw_reset_cnt(0), _wd_reset_cnt(0), _modem_status_handler(NULL), _modem_status(AtCmdFrame::HwReset), _initializing(true), _node_by_ni_frame_id(0)
{

    if (reset != NC) {
        _reset = new DigitalOut(reset, 1);
    }

    _uart = new RawSerial(tx, rx);
    _uart->baud(baud);

    _serial_flow_type = SerialBase::Disabled;
#if defined(DEVICE_SERIAL_FC)
    if (rts != NC && cts != NC) {
        _serial_flow_type = SerialBase::RTSCTS;
        _uart->set_flow_control(_serial_flow_type, rts, cts);
    } else if (rts != NC && cts == NC) {
        _serial_flow_type = SerialBase::RTS;
        _uart->set_flow_control(_serial_flow_type, rts);
    } else if (rts == NC && cts != NC) {
        _serial_flow_type = SerialBase::CTS;
        _uart->set_flow_control(_serial_flow_type, cts);
    }
#endif
    /* Enable the reception of bytes on the serial interface by providing a cb */
    _uart->attach(this, &XBee::uart_read_cb, Serial::RxIrq);

    for (int i = 0; i < MAX_FRAME_HANDLERS; i++) {
        _fhandlers[i] = NULL;
    }
}

/* Class destructor */
XBee::~XBee()
{
    unregister_modem_status_cb();

    if (_uart != NULL) {
        delete _uart;
    }
    if (_reset != NULL) {
        delete _reset;
    }
}

#include <inttypes.h>

RadioStatus XBee::init(void)
{
    AtCmdFrame::AtCmdResp cmd_resp;
    uint32_t var32;

    _initializing = true;

    const unsigned int max_reset_retries = 3;
    RadioStatus reset_status;
    for (unsigned int i = 0; i < max_reset_retries; i++) {
        reset_status = device_reset();
        if (reset_status == Success) {
            break;
        }
    }
    if (reset_status != Success) {
        return reset_status;
    }

    /* Check if radio is in API1 or API2 _mode */
    cmd_resp = get_param("AP", &var32);
    if (cmd_resp != AtCmdFrame::AtCmdRespOk) {
        return Failure;
    }
    _mode = (RadioMode)var32;

    /* Read the device unique 64b address */
    uint32_t serialn_high, serialn_low;
    cmd_resp = get_param("SH", &serialn_high);
    if (cmd_resp != AtCmdFrame::AtCmdRespOk) {
        return Failure;
    }

    cmd_resp = get_param("SL", &serialn_low);
    if (cmd_resp != AtCmdFrame::AtCmdRespOk) {
        return Failure;
    }

    _dev_addr64 = ((uint64_t)serialn_high << 32) | serialn_low;

    /* Read some important parameters */
    cmd_resp = get_param("HV", &var32);
    if (cmd_resp != AtCmdFrame::AtCmdRespOk) {
        return Failure;
    }
    _hw_version = var32;

    cmd_resp = get_param("VR", &var32);
    if (cmd_resp != AtCmdFrame::AtCmdRespOk) {
        return Failure;
    }
    _fw_version = var32;

    digi_log(LogLevelInfo, "mode:   %02x\r\n", (uint8_t)_mode);
    digi_log(LogLevelInfo, "HV:     %04x\r\n", _hw_version);
    digi_log(LogLevelInfo, "VR:     %04x\r\n", _fw_version);
    digi_log(LogLevelInfo, "ADDR64: %08x:%08x\r\n", UINT64_HI32(_dev_addr64), UINT64_LO32(_dev_addr64));

#if defined(DEVICE_SERIAL_FC)
    bool valid_radio_fc = check_radio_flow_control();
    assert(valid_radio_fc == true);
#endif

    _initializing = false;
    if (_modem_status_handler != NULL) {
        const ApiFrame frame = ApiFrame(ApiFrame::AtModemStatus, (uint8_t *)&_modem_status, sizeof(_modem_status));
        _modem_status_handler->process_frame_data(&frame);
    }

    return Success;
}

uint64_t XBee::get_addr64() const
{
    return _dev_addr64;
}

RadioStatus XBee::hardware_reset()
{
    if (_reset != NULL) {
        volatile uint16_t * const rst_cnt_p = &_hw_reset_cnt;
        const uint16_t init_rst_cnt = *rst_cnt_p;
        *_reset = 0;
        wait_ms(10);
        *_reset = 1;
        return wait_for_module_to_reset(rst_cnt_p, init_rst_cnt);
    }

    return Failure;
}

RadioStatus XBee::device_reset()
{
    if (hardware_reset() == Success) {
        return Success;
    }

    return software_reset();
}

RadioStatus XBee::wait_for_module_to_reset(volatile uint16_t *rst_cnt_p, uint16_t init_rst_cnt)
{
    Timer timer = Timer();
    timer.start();

    while (*rst_cnt_p == init_rst_cnt && timer.read_ms() < RESET_TIMEOUT_MS) {
        wait_ms(100);
    }

    if (*rst_cnt_p == init_rst_cnt) {
        digi_log(LogLevelWarning, "Reset Timeout\r\n");
        return Failure;
    }
    return Success;
}

/** Callback function called when data is received on the serial port */
void XBee::uart_read_cb(void)
{
    static uint8_t rxstate = WAITING_FOR_START_FRAME;
    static uint16_t framelen = 0;
    static uint16_t bytes_read;
    static uint8_t chksum;
    static ApiFrame *frame = NULL;
    static bool last_byte_escaped = false;
    static FrameBuffer * framebuf = NULL;

    while (_uart->readable()) {
        uint8_t data = _uart->getc();

        if (IS_API2() && rxstate != WAITING_FOR_START_FRAME) {
            if (last_byte_escaped) {
                data = data ^ DR_ESCAPE_XOR_BYTE;
                last_byte_escaped = false;
            } else if (data == DR_ESCAPE_BYTE) {
                last_byte_escaped = true;
                continue;
            }
        }

        switch (rxstate) {
            case WAITING_FOR_START_FRAME:
                if (data == DR_START_OF_FRAME) {
                    rxstate = WAITING_FOR_LENGTH_MSB;
                }
                break;

            case WAITING_FOR_LENGTH_MSB:
                framelen = data << 8;
                rxstate = WAITING_FOR_LENGTH_LSB;
                break;

            case WAITING_FOR_LENGTH_LSB:
                framelen |= data;
                rxstate = WAITING_FOR_PAYLOAD;
                bytes_read = 0;
                chksum = 0;
                /* Sanity check that the frame is smaller than... */
                if (framelen > MAX_FRAME_PAYLOAD_LEN) {
                    digi_log(LogLevelDebug, "framelen=%d too long\r\n", framelen);
                    digi_log(LogLevelWarning, "Frame dropped, frame too long. Increase MAX_FRAME_PAYLOAD_LEN define\r\n");
                    rxstate = WAITING_FOR_START_FRAME;
                }
                break;

            case WAITING_FOR_PAYLOAD:
                #define CACHED_SIZE 3
                static uint8_t frame_cached[CACHED_SIZE];

                if (framelen <= CACHED_SIZE) {
                    if (!bytes_read) {
                        const ApiFrame::ApiFrameType frame_type = (ApiFrame::ApiFrameType)data;
                        switch (frame_type)
                        {
                            case ApiFrame::AtCmdResp:
                            case ApiFrame::RemoteCmdResp:
                            case ApiFrame::TxStatusZBDM:
                            case ApiFrame::TxStatus:
                                framebuf = &_framebuf_syncr;
                                break;

                            case ApiFrame::RxPacket64Bit:
                            case ApiFrame::RxPacket16Bit:
                            case ApiFrame::Io64Bit:
                            case ApiFrame::Io16Bit:
                            case ApiFrame::AtModemStatus:
                            case ApiFrame::RxPacketAO0:
                            case ApiFrame::IoSampleRxZBDM:
                                framebuf = &_framebuf_app;
                                break;

                            case ApiFrame::RxPacketAO1:
                            case ApiFrame::SensorRxIndAO0:
                            case ApiFrame::NodeIdentIndAO0:
                            case ApiFrame::OtaFwUpStatus:
                            case ApiFrame::RouteRecInd:
                            case ApiFrame::Many2OneRRInd:
                            case ApiFrame::TxReq64Bit:
                            case ApiFrame::TxReq16Bit:
                            case ApiFrame::AtCmd:
                            case ApiFrame::AtCmdQueuePV:
                            case ApiFrame::TxReqZBDM:
                            case ApiFrame::ExpAddrCmd:
                            case ApiFrame::RemoteCmdReq:
                            case ApiFrame::CreateSrcRoute:
                            case ApiFrame::Invalid:
                            case ApiFrame::RouteInfo:
                            case ApiFrame::AggregateAddr:
                                framebuf = NULL;
                                break;
                        }

                        if (framebuf == NULL) {
                            digi_log(LogLevelWarning, "Discarding not supported frame type %02x\r\n", frame_type);
                            rxstate = WAITING_FOR_START_FRAME;
                        } else {
                            frame = framebuf->get_next_free_frame();
                            if (frame == NULL) {
                                /* It's not possible to achive this condition as we discard older frames and only one frame can be used by syncr. commands */
                                assert(frame != NULL);
                                rxstate = WAITING_FOR_START_FRAME;
                            } else {
                                frame->set_data_len(framelen - 1);
                            }

                            frame->set_frame_type(frame_type);
                        }
                    } else {
                        frame->set_data(data, bytes_read - 1);
                    }
                    chksum += data;
                    bytes_read++;
                    if (bytes_read == framelen) {
                        rxstate = WAITING_FOR_CHECKSUM;
                    }
                    break;
                }


                if (bytes_read < CACHED_SIZE) {
                    frame_cached[bytes_read] = data;
                }
                else if (bytes_read == CACHED_SIZE) {
                    const ApiFrame::ApiFrameType frame_type = (ApiFrame::ApiFrameType)frame_cached[0];
                    switch (frame_type)
                    {
                        case ApiFrame::RemoteCmdResp:
                        case ApiFrame::TxStatusZBDM:
                        case ApiFrame::TxStatus:
                            framebuf = &_framebuf_syncr;
                            break;

                        case ApiFrame::AtCmdResp:
                            if ((frame_cached[1] != _node_by_ni_frame_id ) && (frame_cached[2] == 'N') && (data == 'D'))
                            {
                                framebuf = &_framebuf_app;
                            } else {
                                framebuf = &_framebuf_syncr;
                            }
                            break;

                        case ApiFrame::RxPacket64Bit:
                        case ApiFrame::RxPacket16Bit:
                        case ApiFrame::Io64Bit:
                        case ApiFrame::Io16Bit:
                        case ApiFrame::AtModemStatus:
                        case ApiFrame::RxPacketAO0:
                        case ApiFrame::IoSampleRxZBDM:
                            framebuf = &_framebuf_app;
                            break;

                        case ApiFrame::RxPacketAO1:
                        case ApiFrame::SensorRxIndAO0:
                        case ApiFrame::NodeIdentIndAO0:
                        case ApiFrame::OtaFwUpStatus:
                        case ApiFrame::RouteRecInd:
                        case ApiFrame::Many2OneRRInd:
                        case ApiFrame::TxReq64Bit:
                        case ApiFrame::TxReq16Bit:
                        case ApiFrame::AtCmd:
                        case ApiFrame::AtCmdQueuePV:
                        case ApiFrame::TxReqZBDM:
                        case ApiFrame::ExpAddrCmd:
                        case ApiFrame::RemoteCmdReq:
                        case ApiFrame::CreateSrcRoute:
                        case ApiFrame::Invalid:
                        case ApiFrame::RouteInfo:
                        case ApiFrame::AggregateAddr:
                            framebuf = NULL;
                            break;
                    }

                    if (framebuf == NULL) {
                        digi_log(LogLevelWarning, "Discarding not supported frame type %02x\r\n", frame_type);
                        rxstate = WAITING_FOR_START_FRAME;
                    } else {
                        frame = framebuf->get_next_free_frame();
                        if (frame == NULL) {
                            /* It's not possible to achive this condition as we discard older frames and only one frame can be used by syncr. commands */
                            assert(frame != NULL);
                            rxstate = WAITING_FOR_START_FRAME;
                        } else {
                            frame->set_data_len(framelen - 1);
                        }

                        frame->set_frame_type(frame_type);
                        frame->set_data(frame_cached[1], 0);
                        frame->set_data(frame_cached[2], 1);
                        frame->set_data(data, 2);
                    }
                } else {
                    frame->set_data(data, bytes_read - 1);
                }
                chksum += data;
                bytes_read++;
                if (bytes_read == framelen) {
                    rxstate = WAITING_FOR_CHECKSUM;
                }
                break;

            case WAITING_FOR_CHECKSUM:
                chksum += data;
                if (chksum == 0xFF) {
                    /* We got a valid frame!! */
                    frame->dump();

                    /* If its a _modem status frame, process it to update the status info of the library.
                     * The frame is also queued to allow processing it other handlers registered.
                     * Note that radio_status_update() has to be fast to minimize the impact of processing
                     * the funcion here */
                    if (frame->get_frame_type() == ApiFrame::AtModemStatus) {
                        radio_status_update((AtCmdFrame::ModemStatus)frame->get_data_at(0));
                        if (_initializing) {
                            framebuf->free_frame(frame);
                        } else {
                            framebuf->complete_frame(frame);
                        }
                    } else {
                        framebuf->complete_frame(frame);
                        /* Note, the frame will be released elsewhere, once it has been processed */
                    }
                } else {
                    framebuf->free_frame(frame);
                    digi_log(LogLevelWarning, "Checksum error, got %02x, %02x\r\n", data, chksum);
                }
                /* Intentional fall-through */
            default:
                rxstate = WAITING_FOR_START_FRAME;
                break;
        }
    }
    /* TODO, signal the thread processing incoming frames */
}

/* This is a pure virtual function, but exists here because its called from this class to
 * to update the status of the object, and can be called before the construction of the
 * object has been completed and the virtual functions filled */
void XBee::radio_status_update(AtCmdFrame::ModemStatus modem_status)
{
    UNUSED_PARAMETER(modem_status);
}

void XBee::set_timeout(uint16_t timeout_ms)
{
    this->_timeout_ms = timeout_ms;
}

uint16_t XBee::get_timeout(void) const
{
    return _timeout_ms;
}

ApiFrame * XBee::get_this_api_frame(uint8_t id, ApiFrame::ApiFrameType type,
                                          ApiFrame::ApiFrameType type2)
{
    Timer timer = Timer();
    timer.start();

    while (timer.read_ms() < _timeout_ms) {
        ApiFrame * frame = _framebuf_syncr.get_next_complete_frame();
        if (frame == NULL) {
            wait_ms(10);
            continue;
        }

        if ((frame->get_frame_type() != type) &&
            (frame->get_frame_type() != type2)) {
            _framebuf_syncr.complete_frame(frame);
            wait_ms(1);
            continue;
        }

        if (frame->get_data_at(ATCMD_RESP_FRAME_ID_OFFSET) != id) {
            _framebuf_syncr.complete_frame(frame);
            wait_ms(1);
            continue;
        }

        /* frame found */
        return frame;
    }

    digi_log(LogLevelWarning, "Frame type: %02x, id: %02x, timeout\r\n", (uint8_t)type, id);

    return NULL;
}

void XBee::send_byte_escaping_if(uint8_t data)
{
    if (IS_API2()) {
        switch (data) {
            case DR_START_OF_FRAME:
            case DR_ESCAPE_BYTE:
            case DR_XON_BYTE:
            case DR_XOFF_BYTE:
                _uart->putc(DR_ESCAPE_BYTE);
                _uart->putc(data ^ DR_ESCAPE_XOR_BYTE);
                break;
            default:
                _uart->putc(data);
        }
    } else {
        _uart->putc(data);
    }
}

void XBee::send_api_frame(ApiFrame *frame)
{
    uint8_t chksum;
    const uint8_t *data;
    uint16_t bytes_sent = 0, frame_len;

    frame->dump();

    frame_len = 1 + frame->get_data_len(); /* frame type + frame payload */
    data = frame->get_data();

    /* Send the start of frame delimiter */
    _uart->putc(DR_START_OF_FRAME);

    /* Now the length */
    send_byte_escaping_if((uint8_t)(frame_len >> 8));
    send_byte_escaping_if((uint8_t)frame_len);

    /* Send the Frame type and then the payload */
    chksum = (uint8_t)frame->get_frame_type();
    send_byte_escaping_if(chksum);
    bytes_sent++;

    /* And now, send the packet payload */
    while (bytes_sent++ < frame_len) {
        chksum += *data;
        send_byte_escaping_if(*data++);
    }

    /* And finally send the checksum */
    send_byte_escaping_if(~chksum);
}

RadioStatus XBee::register_frame_handler(FrameHandler *const handler)
{
    if (handler != NULL) {
        for (int i = 0; i < MAX_FRAME_HANDLERS; i++) {
            if (_fhandlers[i] != NULL) {
                continue;
            }
            _fhandlers[i] = handler;
            return Success;
        }
    }

    digi_log(LogLevelError, "No more Frame Handlers available. Increase MAX_FRAME_HANDLERS define\r\n");

    return Failure;
}

RadioStatus XBee::unregister_frame_handler(FrameHandler *const handler)
{
    int i;

    if (handler != NULL) {
        for (i = 0; i < MAX_FRAME_HANDLERS; i++) {
            if (_fhandlers[i] == handler) {
                break;
            }
        }

        if (i == MAX_FRAME_HANDLERS) {
            return Failure;
        }

        do {
            if (i == MAX_FRAME_HANDLERS - 1) {
                _fhandlers[i] = NULL;
            } else {
                _fhandlers[i] = _fhandlers[i + 1];
            }
        } while (++i < MAX_FRAME_HANDLERS);
    }

    return Success;
}

XBee::RadioProtocol XBee::get_radio_protocol(void) const
{
    enum HardwareVersion {
#ifdef EXTRA_XBEE_PROTOCOLS
        X09_009 = 0x01,
        X09_019 = 0x02,
        XH9_009 = 0x03,
        XH9_019 = 0x04,
        X24_009 = 0x05,
        X24_019 = 0x06,
        X09_001 = 0x07,
        XH9_001 = 0x08,
        X08_004 = 0x09,
        XC09_009 = 0x0A,
        XC09_038 = 0x0B,
        X24_038 = 0x0C,
        X09_009_TX = 0x0D,
        X09_019_TX = 0x0E,
        XH9_009_TX = 0x0F,
        XH9_019_TX = 0x10,
        X09_001_TX = 0x11,
        XH9_001_TX = 0x12,
        XT09B_XXX = 0x13,
        XT09_XXX = 0x14,
        XC08_009 = 0x15,
        XC08_038 = 0x16,
#endif
        XB24_AXX_XX = 0x17,
        XBP24_AXX_XX = 0x18,
        XB24_BXIX_XXX = 0x19,
        XBP24_BXIX_XXX = 0x1A,
#ifdef EXTRA_XBEE_PROTOCOLS
        XBP09_DXIX_XXX = 0x1B,
        XBP09_XCXX_XXX = 0x1C,
        XBP08_DXXX_XXX = 0x1D,
#endif
        XBP24B = 0x1E,
#ifdef EXTRA_XBEE_PROTOCOLS
        XB24_WF = 0x1F,
        AMBER_MBUS = 0x20,
#endif
        XBP24C = 0x21,
        XB24C = 0x22,
#ifdef EXTRA_XBEE_PROTOCOLS
        XSC_GEN3 = 0x23,
        SRD_868_GEN3 = 0x24,
        ABANDONATED = 0x25,
        SMT_900LP = 0x26,
        WIFI_ATHEROS = 0x27,
        SMT_WIFI_ATHEROS = 0x28,
        SMT_475LP = 0x29,
        XBEE_CELL_TH = 0x2A,
        XLR_MODULE = 0x2B,
        XB900HP_NZ = 0x2C,
        XBP24C_TH_DIP = 0x2D,
        XB24C_TH_DIP = 0x2E,
        XLR_BASEBOARD = 0x2F,
        XBP24C_S2C_SMT = 0x30
#endif
    };
    const bool fw_4_bytes_len = _fw_version > 0x0FFF && _fw_version < 0xFFFF;
    const uint8_t fw_nibble_3 = (_fw_version >> (4 * 3)) & 0x000F;
    const uint8_t fw_nibble_1 = (_fw_version >> (4 * 1)) & 0x000F;
    const uint8_t fw_nibble_0 = (_fw_version >> (4 * 0)) & 0x000F;
    const uint8_t hw_version_msb = _hw_version >> 8;

    if (hw_version_msb == XB24_AXX_XX || hw_version_msb == XBP24_AXX_XX) {
#ifdef EXTRA_XBEE_PROTOCOLS
        if (fw_4_bytes_len && fw_nibble_3 == 8) {
            return DigiMesh;
        }
        return Raw_802_15_4;
#else
        if (!(fw_4_bytes_len && fw_nibble_3 == 8)) {
            return Raw_802_15_4;
        }
#endif
    } else if (hw_version_msb == XB24_BXIX_XXX || hw_version_msb == XBP24_BXIX_XXX) {
        if (fw_4_bytes_len && ((fw_nibble_3 == 1 && fw_nibble_1 == 2 && fw_nibble_0 == 0) || fw_nibble_3 == 2)) {
            return ZigBee;
        }
#ifdef EXTRA_XBEE_PROTOCOLS
        if (fw_4_bytes_len && fw_nibble_3 == 3) {
            return SmartEnergy;
        }
        return ZNet;
    } else if (hw_version_msb == XBP09_DXIX_XXX) {
        if (fw_4_bytes_len && (fw_nibble_3 == 8 || fw_nibble_1 == 8))  {
            return DigiMesh;
        }
        return DigiPoint;
    } else if (hw_version_msb == XBP08_DXXX_XXX) {
        return DigiPoint;
#endif
    } else if (hw_version_msb == XBP24B) {
#ifdef EXTRA_XBEE_PROTOCOLS
        if (fw_4_bytes_len && fw_nibble_3 == 3) {
            return SmartEnergy;
        }
        return ZigBee;
#else
        if (!(fw_4_bytes_len && fw_nibble_3 == 3)) {
            return ZigBee;
        }
#endif
#ifdef EXTRA_XBEE_PROTOCOLS
    } else if (hw_version_msb == XB24_WF || hw_version_msb == WIFI_ATHEROS || hw_version_msb == SMT_WIFI_ATHEROS) {
        return XBeeWiFi;
#endif
    } else if (hw_version_msb == XBP24C || hw_version_msb == XB24C) {
        if (fw_4_bytes_len && fw_nibble_3 == 2) {
            return Raw_802_15_4;
        }
#ifdef EXTRA_XBEE_PROTOCOLS
        if (fw_4_bytes_len && fw_nibble_3 == 5) {
            return SmartEnergy;
        }
        return ZigBee;
#else
        if (!(fw_4_bytes_len && fw_nibble_3 == 5)) {
            return ZigBee;
        }
#endif
#ifdef EXTRA_XBEE_PROTOCOLS
    } else if (hw_version_msb == XSC_GEN3 || hw_version_msb == SRD_868_GEN3) {
        if (fw_4_bytes_len && fw_nibble_3 == 8) {
            return DigiMesh;
        } else if (fw_4_bytes_len && fw_nibble_3 == 1) {
            return DigiPoint;
        }
        return None;
    } else if (hw_version_msb == XBEE_CELL_TH) {
        return None;
    } else if (hw_version_msb == XLR_MODULE) {
        return None;
    } else if (hw_version_msb == XLR_BASEBOARD) {
        return None;
    } else if (hw_version_msb == XB900HP_NZ) {
        return DigiPoint;
    } else if (hw_version_msb == XBP24C_TH_DIP || hw_version_msb == XB24C_TH_DIP || hw_version_msb == XBP24C_S2C_SMT) {
        if (fw_4_bytes_len && fw_nibble_3 == 9) {
            return DigiMesh;
        }
        if (fw_4_bytes_len && fw_nibble_3 == 5) {
            return SmartEnergy;
        }
        if (fw_4_bytes_len && fw_nibble_3 == 2) {
            return Raw_802_15_4;
        }
        return ZigBee;
    }
#else
    }
#endif

    return None;
}

#define TX_STATUS_OFFSET_ZB     4
#define TX_STATUS_OFFSET_802    1

TxStatus XBee::send_data(ApiFrame *frame)
{
    TxStatus resp = TxStatusTimeout;
    ApiFrame *resp_frame;

    send_api_frame(frame);

    /* Wait for the transmit status response packet */
    resp_frame = get_this_api_frame(frame->get_frame_id(),
                    ApiFrame::TxStatusZBDM, ApiFrame::TxStatus);
    if (resp_frame == NULL) {
        return resp;
    }

    uint8_t index = resp_frame->get_frame_type() == ApiFrame::TxStatusZBDM ?
            TX_STATUS_OFFSET_ZB : TX_STATUS_OFFSET_802;

    resp = (TxStatus)resp_frame->get_data_at(index);

    /* Once processed, remove the frame from the buffer */
    _framebuf_syncr.free_frame(resp_frame);

    return resp;
}

TxStatus XBee::send_data_broadcast(const uint8_t *const data, uint16_t len, bool syncr)
{
    const RemoteXBee remoteDevice = RemoteXBee(ADDR64_BROADCAST);
    return send_data(remoteDevice, data, len, syncr);
}

uint32_t XBee::process_rx_frames()
{
    ApiFrame *frame = NULL;

    while ((frame = _framebuf_app.get_next_complete_frame()) != NULL) {
        for (int i = 0; i < MAX_FRAME_HANDLERS; i++) {

            if (_fhandlers[i] == NULL) {
                /* No more handlers, break here */
                break;
            }

            /* Check if frame and handler match, if not... go for the next one */
            if (frame->get_frame_type() != _fhandlers[i]->get_type()) {
                continue;
            }

            _fhandlers[i]->process_frame_data(frame);
        }

        /* Once processed, remove the frame from the buffer */
        _framebuf_app.free_frame(frame);
    }

    const uint32_t dropped_frames = _framebuf_app.get_dropped_frames_count();
    if (dropped_frames != 0) {
        digi_log(LogLevelWarning, "process_rx_frames: %d frames dropped!!!\r\n", dropped_frames);
    }

    return dropped_frames;
}

void XBee::register_modem_status_cb(modem_status_cb_t function)
{
    if (_modem_status_handler == NULL) {
        _modem_status_handler = new FH_ModemStatus();
        register_frame_handler(_modem_status_handler);
    }
    _modem_status_handler->register_modem_status_cb(function);
}

void XBee::unregister_modem_status_cb()
{
    if (_modem_status_handler != NULL) {
        _modem_status_handler->unregister_modem_status_cb();
        unregister_frame_handler(_modem_status_handler);
        delete _modem_status_handler;
        _modem_status_handler = NULL; /* as delete does not set to NULL */
    }
}

int XBee::get_AI(void)
{
    uint32_t atai;
    const AtCmdFrame::AtCmdResp status = get_param("AI", &atai);

    if (status != AtCmdFrame::AtCmdRespOk) {
        digi_log(LogLevelError, "get_association_indication() failed with %d\r\n", status);
        return -1;
    }
    return atai;
}