Add receive callback mode using DIO0

Author: sandeepmistry

API.md

@@ -24,10 +24,11 @@ Returns `1` on success, `0` on failure.
 Override the default `NSS` and `NRESET` pins used by the library. **Must** be called before `LoRa.begin()`.
 
 ```arduino
-LoRa.setPins(ss, reset);
+LoRa.setPins(ss, reset, dio0);
 ```
  * `ss` new slave select pin to use, defaults to `10`
  * `reset` new reset pin to use, defaults to `9`
+ * `dio0` new DIO0 pin to use, defaults to `2`
 
 ### End
 

README.md

@@ -21,9 +21,10 @@ An [Arduino](http://arduino.cc/) library for sending and receiving data using [L
 | MOSI | MOSI |
 | NSS | 10 |
 | NRESET | 9 |
+| DIO0 | 2 |
 
 
-`NSS` and `NRESET` pins can be changed by using `LoRa.setPins(ss, reset)`.
+`NSS`, `NRESET`, and `DIO0` pins can be changed by using `LoRa.setPins(ss, reset, dio0)`. `DIO0` pin is optional, it is only needed for receive callback mode.
 
 ## Installation
 

examples/LoRaReceiverCallback/LoRaReceiverCallback.ino

@@ -0,0 +1,39 @@
+#include <SPI.h>
+#include <LoRa.h>
+
+void setup() {
+  Serial.begin(9600);
+  while (!Serial);
+
+  Serial.println("LoRa Receiver Callback");
+
+  if (!LoRa.begin(915E6)) {
+    Serial.println("Starting LoRa failed!");
+    while (1);
+  }
+
+  // register the receive callback
+  LoRa.onReceive(onReceive);
+
+  // put the radio into receive mode
+  LoRa.receive();
+}
+
+void loop() {
+  // do nothing
+}
+
+void onReceive(int packetSize) {
+  // received a packet
+  Serial.print("Received packet '");
+
+  // read packet
+  for (int i = 0; i < packetSize; i++) {
+    Serial.print((char)LoRa.read());
+  }
+
+  // print RSSI of packet
+  Serial.print("' with RSSI ");
+  Serial.println(LoRa.packetRssi());
+}
+

keywords.txt

@@ -28,6 +28,11 @@ read	KEYWORD2
 peek	KEYWORD2
 flush	KEYWORD2
 
+onReceive	KEYWORD2
+receive	KEYWORD2
+idle	KEYWORD2
+sleep	KEYWORD2
+
 setPins	KEYWORD2
 dumpRegisters	KEYWORD2
 

src/LoRa.cpp

@@ -15,13 +15,15 @@
 #define REG_RX_NB_BYTES          0x13
 #define REG_PKT_RSSI_VALUE       0x1a
 #define REG_PAYLOAD_LENGTH       0x22
+#define REG_DIO_MAPPING_1        0x40
 #define REG_VERSION              0x42
 
 // modes
 #define MODE_LONG_RANGE_MODE     0x80
 #define MODE_SLEEP               0x00
 #define MODE_STDBY               0x01
 #define MODE_TX                  0x03
+#define MODE_RX_CONTINUOUS       0x05
 #define MODE_RX_SINGLE           0x06
 
 // PA config
@@ -35,9 +37,10 @@
 
 LoRaClass::LoRaClass() :
   _spiSettings(10E6, MSBFIRST, SPI_MODE0),
-  _ss(10), _reset(9),
+  _ss(LORA_DEFAULT_SS_PIN), _reset(LORA_DEFAULT_RESET_PIN), _dio0(LORA_DEFAULT_DIO0_PIN),
   _frequency(0),
-  _packetIndex(0)
+  _packetIndex(0),
+  _onReceive(NULL)
 {
 }
 
@@ -225,10 +228,39 @@ void LoRaClass::flush()
 {
 }
 
-void LoRaClass::setPins(int ss, int reset)
+void LoRaClass::onReceive(void(*callback)(int))
+{
+  _onReceive = callback;
+
+  if (callback) {
+    writeRegister(REG_DIO_MAPPING_1, 0x00);
+
+    attachInterrupt(digitalPinToInterrupt(_dio0), LoRaClass::onDio0Rise, RISING);
+  } else {
+    detachInterrupt(digitalPinToInterrupt(_dio0));
+  }
+}
+
+void LoRaClass::receive()
+{
+  writeRegister(REG_OP_MODE, MODE_LONG_RANGE_MODE | MODE_RX_CONTINUOUS);
+}
+
+void LoRaClass::idle()
+{
+  writeRegister(REG_OP_MODE, MODE_LONG_RANGE_MODE | MODE_STDBY);
+}
+
+void LoRaClass::sleep()
+{
+  writeRegister(REG_OP_MODE, MODE_LONG_RANGE_MODE | MODE_SLEEP);
+}
+
+void LoRaClass::setPins(int ss, int reset, int dio0)
 {
   _ss = ss;
   _reset = reset;
+  _dio0 = dio0;
 }
 
 void LoRaClass::dumpRegisters(Stream& out)
@@ -241,6 +273,30 @@ void LoRaClass::dumpRegisters(Stream& out)
   }
 }
 
+void LoRaClass::handleDio0Rise()
+{
+  int irqFlags = readRegister(REG_IRQ_FLAGS);
+
+  // clear IRQ's
+  writeRegister(REG_IRQ_FLAGS, irqFlags);
+
+  // received a packet
+  _packetIndex = 0;
+
+  // read packet length
+  int packetLength = readRegister(REG_RX_NB_BYTES);
+
+  // set FIFO address to current RX address
+  writeRegister(REG_FIFO_ADDR_PTR, readRegister(REG_FIFO_RX_CURRENT_ADDR));
+
+  if (_onReceive) {
+    _onReceive(packetLength);
+  }
+
+  // reset FIFO address
+  writeRegister(REG_FIFO_ADDR_PTR, 0);
+}
+
 uint8_t LoRaClass::readRegister(uint8_t address)
 {
   return singleTransfer(address & 0x7f, 0x00);
@@ -267,4 +323,9 @@ uint8_t LoRaClass::singleTransfer(uint8_t address, uint8_t value)
   return response;
 }
 
+void LoRaClass::onDio0Rise()
+{
+  LoRa.handleDio0Rise();
+}
+
 LoRaClass LoRa;

src/LoRa.h

@@ -4,6 +4,10 @@
 #include <Arduino.h>
 #include <SPI.h>
 
+#define LORA_DEFAULT_SS_PIN    10
+#define LORA_DEFAULT_RESET_PIN 9
+#define LORA_DEFAULT_DIO0_PIN  2
+
 class LoRaClass : public Stream {
 public:
   LoRaClass();
@@ -27,21 +31,33 @@ class LoRaClass : public Stream {
   virtual int peek();
   virtual void flush();
 
-  void setPins(int ss, int reset);
+  void onReceive(void(*callback)(int));
+
+  void receive();
+  void idle();
+  void sleep();
+
+  void setPins(int ss = LORA_DEFAULT_SS_PIN, int reset = LORA_DEFAULT_RESET_PIN, int dio0 = LORA_DEFAULT_DIO0_PIN);
 
   void dumpRegisters(Stream& out);
 
 private:
+  void handleDio0Rise();
+
   uint8_t readRegister(uint8_t address);
   void writeRegister(uint8_t address, uint8_t value);
   uint8_t singleTransfer(uint8_t address, uint8_t value);
 
+  static void onDio0Rise();
+
 private:
   SPISettings _spiSettings;
   int _ss;
   int _reset;
+  int _dio0;
   int _frequency;
   int _packetIndex;
+  void (*_onReceive)(int);
 };
 
 extern LoRaClass LoRa;