Updated interrupt based blocking callback to loop based non-blocking one

API.md

@@ -127,7 +127,9 @@ Returns `1` on success, `0` on failure.
 
 ### Register callback
 
-Register a callback function for when a packet transmission finish.
+Register a callback function for when a packet transmission finish. `NOTE:` Only write simple
+function to manipulate a state variable. Then use the variable to do action in loop(). Also,
+delay() will not work as it is an interrupt callback.
 
 ```arduino
 LoRa.onTxDone(onTxDone);
@@ -162,7 +164,9 @@ Returns the packet size in bytes or `0` if no packet was received.
 
 #### Register callback
 
-Register a callback function for when a packet is received.
+Register a callback function for when a packet is received. `NOTE:` Only write simple
+function to manipulate a state variable. Then use the variable to do action in loop(). Also,
+delay() will not work as it is an interrupt callback.
 
 ```arduino
 LoRa.onReceive(onReceive);

examples/LoRaDuplexCallback/LoRaDuplexCallback.ino

@@ -29,6 +29,7 @@ byte localAddress = 0xBB;     // address of this device
 byte destination = 0xFF;      // destination to send to
 long lastSendTime = 0;        // last send time
 int interval = 2000;          // interval between sends
+int packetReceived = 0;       // keeps track of packetReceived for onReceiveCallback
 
 void setup() {
   Serial.begin(9600);                   // initialize serial
@@ -44,12 +45,16 @@ void setup() {
     while (true);                       // if failed, do nothing
   }
 
-  LoRa.onReceive(onReceive);
+  // onReceive calls interrupt internally. should run only tiny amount of code
+  // any heavylifting should handled in the loop
+  // also, should not contain any timer based delay calls
+  LoRa.onReceive([](int packetLength) { packetReceived = packetLength; });
   LoRa.receive();
   Serial.println("LoRa init succeeded.");
 }
 
 void loop() {
+  if (packetReceived) onReceive();
   if (millis() - lastSendTime > interval) {
     String message = "HeLoRa World!";   // send a message
     sendMessage(message);
@@ -71,8 +76,8 @@ void sendMessage(String outgoing) {
   msgCount++;                           // increment message ID
 }
 
-void onReceive(int packetSize) {
-  if (packetSize == 0) return;          // if there's no packet, return
+void onReceive() {
+  if (!packetReceived) return;          // if there's no packet, return
 
   // read packet header bytes:
   int recipient = LoRa.read();          // recipient address
@@ -106,5 +111,8 @@ void onReceive(int packetSize) {
   Serial.println("RSSI: " + String(LoRa.packetRssi()));
   Serial.println("Snr: " + String(LoRa.packetSnr()));
   Serial.println();
+
+  packetReceived = 0;                   // reset packetReceived so that
+                                        // onReceive only runs once per packet
 }
 

examples/LoRaReceiverCallback/LoRaReceiverCallback.ino

@@ -5,6 +5,8 @@
 #error "This example is not compatible with the Arduino MKR WAN 1300 board!"
 #endif
 
+int packetReceived = 0;  // keeps track of packetReceived for onReceiveCallback
+
 void setup() {
   Serial.begin(9600);
   while (!Serial);
@@ -20,26 +22,32 @@ void setup() {
   // LoRa.setGain(6);
 
   // register the receive callback
-  LoRa.onReceive(onReceive);
+  // onReceive calls interrupt internally. should run only tiny amount of code
+  // any heavylifting should handled in the loop
+  // also, should not contain any timer based delay calls
+  LoRa.onReceive([](int packetLength) { packetReceived = packetLength; });
 
   // put the radio into receive mode
   LoRa.receive();
 }
 
 void loop() {
-  // do nothing
+  if (packetReceived) onReceive();
 }
 
-void onReceive(int packetSize) {
+void onReceive() {
   // received a packet
   Serial.print("Received packet '");
 
   // read packet
-  for (int i = 0; i < packetSize; i++) {
+  for (int i = 0; i < packetReceived; i++) {
     Serial.print((char)LoRa.read());
   }
 
   // print RSSI of packet
   Serial.print("' with RSSI ");
   Serial.println(LoRa.packetRssi());
+
+  // reset packetReceived so that onReceive only runs once per packet
+  packetReceived = 0;
 }

examples/LoRaSenderNonBlockingCallback/LoRaSenderNonBlockingCallback.ino

@@ -1,7 +1,8 @@
 #include <SPI.h>
 #include <LoRa.h>
 
-int counter = 0;
+int  counter = 0;
+bool txDone  = false; // keeps track of txDone for onTxDone
 
 void setup() {
   Serial.begin(9600);
@@ -14,10 +15,14 @@ void setup() {
     while (1);
   }
 
-  LoRa.onTxDone(onTxDone);
+  // onTxDone calls interrupt internally. should run only tiny amount of code
+  // any heavylifting should handled in the loop
+  // also, should not contain any timer based delay calls
+  LoRa.onTxDone([] { txDone = true; });
 }
 
 void loop() {
+  if (txDone) onTxDone();
   if (runEvery(5000)) { // repeat every 5000 millis
 
     Serial.print("Sending packet non-blocking: ");
@@ -35,6 +40,8 @@ void loop() {
 
 void onTxDone() {
   Serial.println("TxDone");
+  txDone = false;         // reset packetReceived so that
+                          // onTxDone only runs once per tx
 }
 
 boolean runEvery(unsigned long interval)

examples/LoRaSimpleGateway/LoRaSimpleGateway.ino

@@ -32,6 +32,8 @@ const long frequency = 915E6;  // LoRa Frequency
 const int csPin = 10;          // LoRa radio chip select
 const int resetPin = 9;        // LoRa radio reset
 const int irqPin = 2;          // change for your board; must be a hardware interrupt pin
+int packetReceived = 0;        // keeps track of packetReceived for onReceiveCallback
+bool txDone  = false;          // keeps track of txDone for onTxDone
 
 void setup() {
   Serial.begin(9600);                   // initialize serial
@@ -52,12 +54,22 @@ void setup() {
   Serial.println("Rx: invertIQ disable");
   Serial.println();
 
-  LoRa.onReceive(onReceive);
-  LoRa.onTxDone(onTxDone);
+  // register the receive callback
+  // onReceive calls interrupt internally. should run only tiny amount of code
+  // any heavylifting should handled in the loop
+  // also, should not contain any timer based delay calls
+  LoRa.onReceive([](int packetLength) { packetReceived = packetLength; });
+
+  // onTxDone calls interrupt internally. should run only tiny amount of code
+  // any heavylifting should handled in the loop
+  // also, should not contain any timer based delay calls
+  LoRa.onTxDone([] { txDone = true; });
   LoRa_rxMode();
 }
 
 void loop() {
+  if (txDone) onTxDone();
+  if (packetReceived) onReceive();
   if (runEvery(5000)) { // repeat every 5000 millis
 
     String message = "HeLoRa World! ";
@@ -87,7 +99,7 @@ void LoRa_sendMessage(String message) {
   LoRa.endPacket(true);                 // finish packet and send it
 }
 
-void onReceive(int packetSize) {
+void onReceive() {
   String message = "";
 
   while (LoRa.available()) {
@@ -96,11 +108,17 @@ void onReceive(int packetSize) {
 
   Serial.print("Gateway Receive: ");
   Serial.println(message);
+
+  packetReceived = 0;                   // reset packetReceived so that
+                                        // onReceive only runs once per packet
 }
 
 void onTxDone() {
   Serial.println("TxDone");
   LoRa_rxMode();
+
+  txDone = false;                       // reset packetReceived so that
+                                        // onTxDone only runs once per tx
 }
 
 boolean runEvery(unsigned long interval)

examples/LoRaSimpleNode/LoRaSimpleNode.ino

@@ -32,6 +32,8 @@ const long frequency = 915E6;  // LoRa Frequency
 const int csPin = 10;          // LoRa radio chip select
 const int resetPin = 9;        // LoRa radio reset
 const int irqPin = 2;          // change for your board; must be a hardware interrupt pin
+int packetReceived = 0;        // keeps track of packetReceived for onReceiveCallback
+bool txDone  = false;          // keeps track of txDone for onTxDone
 
 void setup() {
   Serial.begin(9600);                   // initialize serial
@@ -52,12 +54,22 @@ void setup() {
   Serial.println("Rx: invertIQ enable");
   Serial.println();
 
-  LoRa.onReceive(onReceive);
-  LoRa.onTxDone(onTxDone);
+  // register the receive callback
+  // onReceive calls interrupt internally. should run only tiny amount of code
+  // any heavylifting should handled in the loop
+  // also, should not contain any timer based delay calls
+  LoRa.onReceive([](int packetLength) { packetReceived = packetLength; });
+
+  // onTxDone calls interrupt internally. should run only tiny amount of code
+  // any heavylifting should handled in the loop
+  // also, should not contain any timer based delay calls
+  LoRa.onTxDone([] { txDone = true; });
   LoRa_rxMode();
 }
 
 void loop() {
+  if (txDone) onTxDone();
+  if (packetReceived) onReceive();
   if (runEvery(1000)) { // repeat every 1000 millis
 
     String message = "HeLoRa World! ";
@@ -87,7 +99,7 @@ void LoRa_sendMessage(String message) {
   LoRa.endPacket(true);                 // finish packet and send it
 }
 
-void onReceive(int packetSize) {
+void onReceive() {
   String message = "";
 
   while (LoRa.available()) {
@@ -96,11 +108,17 @@ void onReceive(int packetSize) {
 
   Serial.print("Node Receive: ");
   Serial.println(message);
+
+  packetReceived = 0;                 // reset packetReceived so that
+                                      // onReceive only runs once per packet
 }
 
 void onTxDone() {
   Serial.println("TxDone");
   LoRa_rxMode();
+
+  txDone = false;                     // reset packetReceived so that
+                                      // onTxDone only runs once per tx
 }
 
 boolean runEvery(unsigned long interval)