A simple LoRa ping-pong application for the LoRa-E5 module by Seeed Studio

LoRaE5Test.c

/*
 * Copyright (c) 2022 Mark Zachmann
 * Merged blinky, lora\receive, and lora\send from the Zephyr samples
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/device.h>
#include <zephyr/drivers/lora.h>
#include <errno.h>
#include <zephyr/sys/util.h>
#include <zephyr/kernel.h>
#include <zephyr/drivers/gpio.h>

#define DEFAULT_RADIO_NODE DT_ALIAS(lora0)
BUILD_ASSERT(DT_NODE_HAS_STATUS(DEFAULT_RADIO_NODE, okay),
	     "No default LoRa radio specified in DT");

#define MAX_DATA_LEN 255
// time to wait before sending a packet after reception
#define SLEEP_TIME_MS   1000

#define LOG_LEVEL CONFIG_LOG_DEFAULT_LEVEL
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(lora_receive);

/* The devicetree node identifier for the "led0" alias. */
#define LED0_NODE DT_ALIAS(led0)
static const struct gpio_dt_spec led = GPIO_DT_SPEC_GET(LED0_NODE, gpios);

// clear the data area so we ensure we are receiving
void clearData(uint8_t* pdata)
{
	for(int i=0; i<MAX_DATA_LEN; i++)
		pdata[i] = 0;
}

// configure reception
int configureRx(const struct device *const lora_dev)
{
	struct lora_modem_config config;
	config.frequency = 915000000;
	config.bandwidth = BW_125_KHZ;
	config.datarate = SF_10;
	config.preamble_len = 8;
	config.coding_rate = CR_4_5;
	config.iq_inverted = false;
	config.public_network = false;
	config.tx_power = 14;
	config.tx = false;

	int ret = lora_config(lora_dev, &config);
	if (ret < 0) {
		LOG_ERR("LoRa config failed");
	}
	return ret;
}

// configure transmission
int configureTx(const struct device *const lora_dev)
{
	struct lora_modem_config config;
	config.frequency = 915000000;
	config.bandwidth = BW_125_KHZ;
	config.datarate = SF_10;
	config.preamble_len = 8;
	config.coding_rate = CR_4_5;
	config.iq_inverted = false;
	config.public_network = false;
	config.tx_power = 14;
	config.tx = true;

	int ret = lora_config(lora_dev, &config);
	if (ret < 0) {
		LOG_ERR("LoRa config failed");
	}
	return ret;
}

// MAIN
void main(void)
{
	const struct device *const lora_dev = DEVICE_DT_GET(DEFAULT_RADIO_NODE);
	int ret, len;
	uint8_t data[MAX_DATA_LEN] = {0};
	int16_t rssi;
	int8_t snr;
	int8_t cntr = '0';

	// initialize the led output pin
	ret = gpio_pin_configure_dt(&led, GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
		return;
	}

	// initialize the LoRa device
	if (!device_is_ready(lora_dev)) {
		LOG_ERR("%s Device not ready", lora_dev->name);
		return;
	}

	// send and receive
	LOG_INF("Starting the cycle");
	for (int i = 0; i < 10; i++) {
		// wait for a packet
		gpio_pin_set_dt(&led, 1);
		clearData(data);

		// receive data
		configureRx(lora_dev);
		LOG_INF("Receiving data.");
		len = lora_recv(lora_dev, data, MAX_DATA_LEN, K_SECONDS(5), &rssi, &snr);
 		if (len < 0) {
			// if we didn't get a packet just reset the counter
			LOG_ERR("LoRa receive failed");
			cntr = '0';
		}
		else {
			// we did get a packet, read the sent counter and increment it
			LOG_INF("Received data: %s (RSSI:%ddBm, SNR:%ddBm)", data, rssi, snr);
			cntr = ++data[1];
			k_sleep(K_MSEC(SLEEP_TIME_MS));
			if(cntr < '0' || cntr > '9')
				cntr = '0';
		}

		// prep to send a packet
		gpio_pin_set_dt(&led, 0);
		clearData(data);
		data[0] = 'N';
		data[1] = cntr;

		// send a packet
		LOG_INF("Sending data.");
		configureTx(lora_dev);
		ret = lora_send(lora_dev, data, 2);
		if (ret < 0) {
			LOG_ERR("LoRa send failed");
		}
	}

	// go to sleep
	LOG_INF("Going to sleep.");
	gpio_pin_set_dt(&led, 0);
	k_sleep(K_FOREVER);
}

prj.conf

CONFIG_LOG=y
CONFIG_SPI=y
CONFIG_GPIO=y
CONFIG_LORA=y
CONFIG_LORA_SX12XX=y
CONFIG_PRINTK=y
CONFIG_CONSOLE=y