Unable to send/receive Lora data

Question

Dear Community;

I am trying to send some data via Lora with a nRF9160 connected with SPI to RF95W Lora module. The transmitter is a nRF9160 with a RF95W, and the receiver is a Raspberry Pi, also with a RF95W.

My transmitter code for nRF9160 is the one located in /zephyr/samples/drivers/lora/send:

/*
 * Copyright (c) 2019 Manivannan Sadhasivam
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <device.h>
#include <drivers/lora.h>
#include <errno.h>
#include <sys/util.h>
#include <zephyr.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 DEFAULT_RADIO DT_LABEL(DEFAULT_RADIO_NODE)

#define MAX_DATA_LEN 10

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

char data[MAX_DATA_LEN] = {'h', 'e', 'l', 'l', 'o', 'w', 'o', 'r', 'l', 'd'};

void main(void)
{
	printk("\nStarting...\n");
	const struct device *lora_dev;
	struct lora_modem_config config;
	int ret;

	lora_dev = device_get_binding(DEFAULT_RADIO);
	if (!lora_dev) {
		printk("%s Device not found", DEFAULT_RADIO);
		return;
	}

	//config.frequency = 865100000;
	config.frequency = 868000000;
	config.bandwidth = BW_125_KHZ;
	config.datarate = SF_10;
	config.preamble_len = 8;
	config.coding_rate = CR_4_8;
	config.tx_power = 17;
	config.tx = true;

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

	while (1) {

		ret = lora_send(lora_dev, data, MAX_DATA_LEN);
		if (ret < 0) {
			printk("LoRa send failed");
			return;
		}

		printk("\nData sent!");

		/* Send data at 1s interval */
		k_sleep(K_MSEC(1000));
	}
}

this is the .overlay file:

/ {
	aliases {
		lora0 = &lora;
	};
};

&uart0 {
    current-speed = <115200>;
    status = "okay";
    tx-pin = <23>;
    rx-pin = <24>;
};

&uart1 {
    status = "disabled";
};


&spi3 {
compatible = "nordic,nrf-spim";
status = "okay";
sck-pin = <20>;
mosi-pin = <21>;
miso-pin = <22>;
cs-gpios = <&gpio0 19 GPIO_ACTIVE_LOW>;

lora: sx1276@0 {
	compatible = "semtech,sx1276";
	reg = <0>;
	label = "sx1276";
	reset-gpios = <&gpio0 3 GPIO_ACTIVE_LOW>;
	dio-gpios = <&gpio0 1 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>,
		<&gpio0 2 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>,
		<&gpio0 3 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>,
		<&gpio0 4 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>,
		<&gpio0 5 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>;
	spi-max-frequency = <1000000>;
	power-amplifier-output = "pa-boost";		
};
};

The connection between nRF and RF95W is the following:

3V --> 3V

GND --> GND

MOSI --> MOSI

MISO --> MISO

SCK --> SCK

GPIO 19 --> NSS(Chip select)

Then, I have an antenna connected to RF95W antenna pin.

Firts thing I don´t understand is regarding to this piece of code:

	lora_dev = device_get_binding(DEFAULT_RADIO);
	if (!lora_dev) {
		printk("%s Device not found", DEFAULT_RADIO);
		return;
	}

The program never enters in that if statement, also with the RF95W module completely disconnected... Also with the RF95W completely disconnected, I don´t get any error at lora_config() or lora_send() functions.

I only thing I have noticed is that if I have the RF95W and nRF9160 well conneted I see this information:

I: SX1276 Version:12 found

If I disconnect NSS(Chip select) I get:

I: SX1276 Version:ff found

If I disconnect 3V I get:

I: SX1276 Version:00 found

However, as mentioned before, I don´t get any errors in the program and I get "Data Sent!" print.

I also know that the Raspberry + RF95W receiver works fine, because we have been able to transmit data to it from another Raspberry + RF95W from 1km distance.

It is very important to us making RF95W work, and we don´t know that else we can try, best regards.