ProMini-LoRaSimpleGateway.ino

/*
	LoRa Simple Gateway/Node Exemple

	This code uses InvertIQ function to create a simple Gateway/Node logic.

	Gateway - Sends messages with enableInvertIQ()
					- Receives messages with disableInvertIQ()

	Node		- Sends messages with disableInvertIQ()
					- Receives messages with enableInvertIQ()

	With this arrangement a Gateway never receive messages from another Gateway
	and a Node never receive message from another Node.
	Only Gateway to Node and vice versa.

	This code receives messages and sends a message every second.

	InvertIQ function basically invert the LoRa I and Q signals.

	See the Semtech datasheet, http://www.semtech.com/images/datasheet/sx1276.pdf
	for more on InvertIQ register 0x33.

	created 05 August 2018
	by Luiz H. Cassettari
*/

#include <SPI.h>							// include libraries
#include <LoRa.h>

const long frequency = 915E6;	// LoRa Frequency

const int csPin = 15;					// LoRa radio chip select
const int resetPin = 14;				// LoRa radio reset
const int irqPin = 2;					// change for your board; must be a hardware interrupt pin

void setup() {
	Serial.begin(9600);									 // initialize serial
	while (!Serial);

	LoRa.setPins(csPin, resetPin, irqPin);
	
	if (!LoRa.begin(frequency)) {
		Serial.println("LoRa init failed. Check your connections.");
		while (true);											 // if failed, do nothing
	}

	Serial.println("LoRa init succeeded.");
	Serial.println();
	Serial.println("LoRa Simple Gateway");
	Serial.println("Only receive messages from nodes");
	Serial.println("Tx: invertIQ enable");
	Serial.println("Rx: invertIQ disable");
	Serial.println();
	
	LoRa.enableCrc();
	LoRa.onReceive(onReceive);
	LoRa.onTxDone(onTxDone);
	LoRa_rxMode();
}

void loop() {
	if (runEvery(5000)) { // repeat every 5000 millis

		String message = "HeLoRa World! ";
		message += "I'm a Gateway! ";
		message += millis();

		LoRa_sendMessage(message); // send a message

		Serial.println("Send Message!");
	}
}

void LoRa_rxMode(){
	LoRa.disableInvertIQ();							 // normal mode
	LoRa.receive();											 // set receive mode
}

void LoRa_txMode(){
	LoRa.idle();													// set standby mode
	LoRa.enableInvertIQ();								// active invert I and Q signals
}

void LoRa_sendMessage(String message) {
	LoRa_txMode();												// set tx mode
	LoRa.beginPacket();									 // start packet
	LoRa.print(message);									// add payload
	LoRa.endPacket(true);								 // finish packet and send it
}

void onReceive(int packetSize) {
	String message = "";

	while (LoRa.available()) {
		message += (char)LoRa.read();
	}

	Serial.print("Gateway Receive: ");
	Serial.println(message);
}

void onTxDone() {
	Serial.println("TxDone");
	LoRa_rxMode();
}

boolean runEvery(unsigned long interval)
{
	static unsigned long previousMillis = 0;
	unsigned long currentMillis = millis();
	if (currentMillis - previousMillis >= interval)
	{
		previousMillis = currentMillis;
		return true;
	}
	return false;
}