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LoRa radio driver

LoRaRadio is a pure virtual class that defines APIs for a LoRa radio driver.

An implementation of this class is passed to the Arm Mbed LoRaWAN stack. Please see existing Mbed OS supported drivers for more information.

To configure this class, please see the LoRa configuration documentation.

LoRaRadio class reference

Public Member Functions
virtual void init_radio (radio_events_t *events)=0
 Registers radio events with the Mbed LoRaWAN stack and undergoes initialization steps, if any. More...
virtual void radio_reset ()=0
 Resets the radio module. More...
virtual void sleep (void)=0
 Put the RF module in sleep mode. More...
virtual void standby (void)=0
 Sets the radio to standby mode. More...
virtual void set_rx_config (radio_modems_t modem, uint32_t bandwidth, uint32_t datarate, uint8_t coderate, uint32_t bandwidth_afc, uint16_t preamble_len, uint16_t symb_timeout, bool fix_len, uint8_t payload_len, bool crc_on, bool freq_hop_on, uint8_t hop_period, bool iq_inverted, bool rx_continuous)=0
 Sets reception parameters. More...
virtual void set_tx_config (radio_modems_t modem, int8_t power, uint32_t fdev, uint32_t bandwidth, uint32_t datarate, uint8_t coderate, uint16_t preamble_len, bool fix_len, bool crc_on, bool freq_hop_on, uint8_t hop_period, bool iq_inverted, uint32_t timeout)=0
 Sets the transmission parameters. More...
virtual void send (uint8_t *buffer, uint8_t size)=0
 Sends the packet. More...
virtual void receive (void)=0
 Sets the radio to reception mode. More...
virtual void set_channel (uint32_t freq)=0
 Sets the carrier frequency. More...
virtual uint32_t random (void)=0
 Generates a 32 bit random value based on RSSI readings. More...
virtual uint8_t get_status (void)=0
 Gets the radio status. More...
virtual void set_max_payload_length (radio_modems_t modem, uint8_t max)=0
 Sets the maximum payload length. More...
virtual void set_public_network (bool enable)=0
 Sets the network to public or private. More...
virtual uint32_t time_on_air (radio_modems_t modem, uint8_t pkt_len)=0
 Computes the packet time on air for the given payload. More...
virtual bool perform_carrier_sense (radio_modems_t modem, uint32_t freq, int16_t rssi_threshold, uint32_t max_carrier_sense_time)=0
 Performs carrier sensing. More...
virtual void start_cad (void)=0
 Sets the radio to CAD mode. More...
virtual bool check_rf_frequency (uint32_t frequency)=0
 Checks whether the given RF is in range. More...
virtual void set_tx_continuous_wave (uint32_t freq, int8_t power, uint16_t time)=0
 Sets the radio to continuous wave transmission mode. More...
virtual void lock (void)=0
 Acquires exclusive access to this radio. More...
virtual void unlock (void)=0
 Releases exclusive access to this radio. More...

LoRaRadio example

/**
 * Copyright (c) 2017, Arm Limited and affiliates.
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include <stdio.h>

#include "lorawan/LoRaWANInterface.h"
#include "lorawan/system/lorawan_data_structures.h"
#include "events/EventQueue.h"

// Application helpers
#include "DummySensor.h"
#include "trace_helper.h"
#include "lora_radio_helper.h"

using namespace events;

// Max payload size can be LORAMAC_PHY_MAXPAYLOAD.
// This example only communicates with much shorter messages (<30 bytes).
// If longer messages are used, these buffers must be changed accordingly.
uint8_t tx_buffer[30];
uint8_t rx_buffer[30];

/*
 * Sets up an application dependent transmission timer in ms. Used only when Duty Cycling is off for testing
 */
#define TX_TIMER                        10000

/**
 * Maximum number of events for the event queue.
 * 10 is the safe number for the stack events, however, if application
 * also uses the queue for whatever purposes, this number should be increased.
 */
#define MAX_NUMBER_OF_EVENTS            10

/**
 * Maximum number of retries for CONFIRMED messages before giving up
 */
#define CONFIRMED_MSG_RETRY_COUNTER     3

/**
 * Dummy pin for dummy sensor
 */
#define PC_9                            0

/**
 * Dummy sensor class object
 */
DS1820  ds1820(PC_9);

/**
* This event queue is the global event queue for both the
* application and stack. To conserve memory, the stack is designed to run
* in the same thread as the application and the application is responsible for
* providing an event queue to the stack that will be used for ISR deferment as
* well as application information event queuing.
*/
static EventQueue ev_queue(MAX_NUMBER_OF_EVENTS *EVENTS_EVENT_SIZE);

/**
 * Event handler.
 *
 * This will be passed to the LoRaWAN stack to queue events for the
 * application which in turn drive the application.
 */
static void lora_event_handler(lorawan_event_t event);

/**
 * Constructing Mbed LoRaWANInterface and passing it the radio object from lora_radio_helper.
 */
static LoRaWANInterface lorawan(radio);

/**
 * Application specific callbacks
 */
static lorawan_app_callbacks_t callbacks;

/**
 * Entry point for application
 */
int main(void)
{
    // setup tracing
    setup_trace();

    // stores the status of a call to LoRaWAN protocol
    lorawan_status_t retcode;

    // Initialize LoRaWAN stack
    if (lorawan.initialize(&ev_queue) != LORAWAN_STATUS_OK) {
        printf("\r\n LoRa initialization failed! \r\n");
        return -1;
    }

    printf("\r\n Mbed LoRaWANStack initialized \r\n");

    // prepare application callbacks
    callbacks.events = mbed::callback(lora_event_handler);
    lorawan.add_app_callbacks(&callbacks);

    // Set number of retries in case of CONFIRMED messages
    if (lorawan.set_confirmed_msg_retries(CONFIRMED_MSG_RETRY_COUNTER)
            != LORAWAN_STATUS_OK) {
        printf("\r\n set_confirmed_msg_retries failed! \r\n\r\n");
        return -1;
    }

    printf("\r\n CONFIRMED message retries : %d \r\n",
           CONFIRMED_MSG_RETRY_COUNTER);

    // Enable adaptive data rate
    if (lorawan.enable_adaptive_datarate() != LORAWAN_STATUS_OK) {
        printf("\r\n enable_adaptive_datarate failed! \r\n");
        return -1;
    }

    printf("\r\n Adaptive data  rate (ADR) - Enabled \r\n");

    retcode = lorawan.connect();

    if (retcode == LORAWAN_STATUS_OK ||
            retcode == LORAWAN_STATUS_CONNECT_IN_PROGRESS) {
    } else {
        printf("\r\n Connection error, code = %d \r\n", retcode);
        return -1;
    }

    printf("\r\n Connection - In Progress ...\r\n");

    // make your event queue dispatching events forever
    ev_queue.dispatch_forever();

    return 0;
}

/**
 * Sends a message to the Network Server
 */
static void send_message()
{
    uint16_t packet_len;
    int16_t retcode;
    int32_t sensor_value;

    if (ds1820.begin()) {
        ds1820.startConversion();
        sensor_value = ds1820.read();
        printf("\r\n Dummy Sensor Value = %d \r\n", sensor_value);
        ds1820.startConversion();
    } else {
        printf("\r\n No sensor found \r\n");
        return;
    }

    packet_len = sprintf((char *) tx_buffer, "Dummy Sensor Value is %d",
                         sensor_value);

    retcode = lorawan.send(MBED_CONF_LORA_APP_PORT, tx_buffer, packet_len,
                           MSG_UNCONFIRMED_FLAG);

    if (retcode < 0) {
        retcode == LORAWAN_STATUS_WOULD_BLOCK ? printf("send - WOULD BLOCK\r\n")
        : printf("\r\n send() - Error code %d \r\n", retcode);

        if (retcode == LORAWAN_STATUS_WOULD_BLOCK) {
            //retry in 3 seconds
            if (MBED_CONF_LORA_DUTY_CYCLE_ON) {
                ev_queue.call_in(3000, send_message);
            }
        }
        return;
    }

    printf("\r\n %d bytes scheduled for transmission \r\n", retcode);
    memset(tx_buffer, 0, sizeof(tx_buffer));
}

/**
 * Receive a message from the Network Server
 */
static void receive_message()
{
    uint8_t port;
    int flags;
    int16_t retcode = lorawan.receive(rx_buffer, sizeof(rx_buffer), port, flags);

    if (retcode < 0) {
        printf("\r\n receive() - Error code %d \r\n", retcode);
        return;
    }

    printf(" RX Data on port %u (%d bytes): ", port, retcode);
    for (uint8_t i = 0; i < retcode; i++) {
        printf("%02x ", rx_buffer[i]);
    }
    printf("\r\n");
    
    memset(rx_buffer, 0, sizeof(rx_buffer));
}

/**
 * Event handler
 */
static void lora_event_handler(lorawan_event_t event)
{
    switch (event) {
        case CONNECTED:
            printf("\r\n Connection - Successful \r\n");
            if (MBED_CONF_LORA_DUTY_CYCLE_ON) {
                send_message();
            } else {
                ev_queue.call_every(TX_TIMER, send_message);
            }

            break;
        case DISCONNECTED:
            ev_queue.break_dispatch();
            printf("\r\n Disconnected Successfully \r\n");
            break;
        case TX_DONE:
            printf("\r\n Message Sent to Network Server \r\n");
            if (MBED_CONF_LORA_DUTY_CYCLE_ON) {
                send_message();
            }
            break;
        case TX_TIMEOUT:
        case TX_ERROR:
        case TX_CRYPTO_ERROR:
        case TX_SCHEDULING_ERROR:
            printf("\r\n Transmission Error - EventCode = %d \r\n", event);
            // try again
            if (MBED_CONF_LORA_DUTY_CYCLE_ON) {
                send_message();
            }
            break;
        case RX_DONE:
            printf("\r\n Received message from Network Server \r\n");
            receive_message();
            break;
        case RX_TIMEOUT:
        case RX_ERROR:
            printf("\r\n Error in reception - Code = %d \r\n", event);
            break;
        case JOIN_FAILURE:
            printf("\r\n OTAA Failed - Check Keys \r\n");
            break;
        case UPLINK_REQUIRED:
            printf("\r\n Uplink required by NS \r\n");
            if (MBED_CONF_LORA_DUTY_CYCLE_ON) {
                send_message();
            }
            break;
        default:
            MBED_ASSERT("Unknown Event");
    }
}

// EOF

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