LoRa®

The SenseCAP indicator is embedded with SX1262 LoRa® module, which can realize the p2p communication.

Send Data Packets

This example code demonstrates a basic example of how to use the LoRa® radio module in transmit mode to send data packets in LoRa® mode. It defines the frequency, bandwidth, spreading factor, coding rate, preamble length, and other parameters of the LoRa® modulation scheme.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "esp_log.h"
#include "radio.h"
#include "bsp_board.h"

#define RF_FREQUENCY                                868000000 // Hz
#define LORA_BANDWIDTH                              0         // [0: 125 kHz,
                                                              //  1: 250 kHz,
                                                              //  2: 500 kHz,
                                                              //  3: Reserved]
#define LORA_SPREADING_FACTOR                       12         // [SF7..SF12]
#define LORA_CODINGRATE                             1         // [1: 4/5,
                                                              //  2: 4/6,
                                                              //  3: 4/7,
                                                              //  4: 4/8]
#define LORA_PREAMBLE_LENGTH                        8         // Same for Tx and Rx
#define LORA_SYMBOL_TIMEOUT                         5         // Symbols
#define LORA_FIX_LENGTH_PAYLOAD_ON                  false
#define LORA_IQ_INVERSION_ON                        false

static RadioEvents_t RadioEvents;

static const char *TAG = "app_main";

void OnTxDone( void )
{
    ESP_LOGI(TAG, "OnTxDone");
}

void demo_lora_tx(void)
{
    int cnt = 0;
    ESP_LOGI(TAG, "system start");
    ESP_LOGI(TAG, "demo lora tx");
    ESP_ERROR_CHECK(bsp_board_init());

    RadioEvents.TxDone = OnTxDone;
    Radio.Init( &RadioEvents );

    Radio.SetChannel( RF_FREQUENCY );
    Radio.SetTxConfig( MODEM_LORA,22, 0, LORA_BANDWIDTH,
                                   LORA_SPREADING_FACTOR, LORA_CODINGRATE,
                                   LORA_PREAMBLE_LENGTH, LORA_FIX_LENGTH_PAYLOAD_ON,
                                   true, 0, 0, LORA_IQ_INVERSION_ON, 3000 );

    Radio.SetMaxPayloadLength( MODEM_LORA, 255 );

    while(1) {
        printf("send... %d\n", cnt++);
        Radio.Send( "1234567890", sizeof("1234567890") );
        vTaskDelay(5000 / portTICK_PERIOD_MS);
    }
}

Receive Data Packets

This example code sets up a LoRa® receiver using the SX126x radio module and logs the received packets to the console. It can be used as a starting point for developing LoRa® applications that require receiving data over long distances with low power consumption.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "esp_log.h"
#include "radio.h"
#include "bsp_board.h"

#define RF_FREQUENCY                                868000000 // Hz
#define LORA_BANDWIDTH                              0         // [0: 125 kHz,
                                                              //  1: 250 kHz,
                                                              //  2: 500 kHz,
                                                              //  3: Reserved]
#define LORA_SPREADING_FACTOR                       7         // [SF7..SF12]
#define LORA_CODINGRATE                             1         // [1: 4/5,
                                                              //  2: 4/6,
                                                              //  3: 4/7,
                                                              //  4: 4/8]
#define LORA_PREAMBLE_LENGTH                        8         // Same for Tx and Rx
#define LORA_SYMBOL_TIMEOUT                         5         // Symbols
#define LORA_FIX_LENGTH_PAYLOAD_ON                  false
#define LORA_IQ_INVERSION_ON                        false

static RadioEvents_t RadioEvents;

static const char *TAG = "app_main";

void OnRxDone( uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr )
{
    int i = 0;
    ESP_LOGI(TAG, "rssi:%d dBm, snr:%d dB, len:%d, payload:", rssi, snr, size);
    for( i = 0; i < size; i++) {
        printf("0x%x ",payload[i] );
    }
    printf("\n");
}

void demo_lora_rx(void)
{
    int cnt = 0;
    ESP_LOGI(TAG, "system start");
    ESP_LOGI(TAG, "demo lora rx continue");
    bsp_sx126x_init();

    RadioEvents.RxDone = OnRxDone;
    Radio.Init( &RadioEvents );

    Radio.SetChannel( RF_FREQUENCY );
    Radio.SetTxConfig( MODEM_LORA,22, 0, LORA_BANDWIDTH,
                                   LORA_SPREADING_FACTOR, LORA_CODINGRATE,
                                   LORA_PREAMBLE_LENGTH, LORA_FIX_LENGTH_PAYLOAD_ON,
                                   true, 0, 0, LORA_IQ_INVERSION_ON, 3000 );

    Radio.SetRxConfig( MODEM_LORA, LORA_BANDWIDTH, LORA_SPREADING_FACTOR,
                                   LORA_CODINGRATE, 0, LORA_PREAMBLE_LENGTH,
                                   LORA_SYMBOL_TIMEOUT, LORA_FIX_LENGTH_PAYLOAD_ON,
                                   0, true, 0, 0, LORA_IQ_INVERSION_ON, true );
    Radio.SetMaxPayloadLength( MODEM_LORA, 255 );

    Radio.Rx( 0 );
    while(1) {
        printf("cnt: %d\n", cnt++);
        vTaskDelay(10000 / portTICK_PERIOD_MS);
    }
}

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