RF69 - Added method to set sync word

examples/RF69_Receive/RF69_Receive.ino

@@ -20,6 +20,7 @@ void setup() {
   // Rx bandwidth:                        125.0 kHz
   // frequency deviation:                 50.0 kHz
   // output power:                        13 dBm
+  // sync word:                           0x2D  0x01
   byte state = rf.begin();
   if(state == ERR_NONE) {
     Serial.println(F("success!"));

examples/RF69_Transmit/RF69_Transmit.ino

@@ -20,6 +20,7 @@ void setup() {
   // Rx bandwidth:                        125.0 kHz
   // frequency deviation:                 50.0 kHz
   // output power:                        13 dBm
+  // sync word:                           0x2D  0x01
   byte state = rf.begin();
   if(state == ERR_NONE) {
     Serial.println(F("success!"));

keywords.txt

@@ -100,10 +100,12 @@ ERR_INVALID_FREQUENCY	LITERAL1
 ERR_INVALID_OUTPUT_POWER	LITERAL1
 PREAMBLE_DETECTED	LITERAL1
 CHANNEL_FREE	LITERAL1
+
 ERR_INVALID_BIT_RATE	LITERAL1
 ERR_INVALID_FREQUENCY_DEVIATION	LITERAL1
 ERR_INVALID_BIT_RATE_BW_RATIO	LITERAL1
 ERR_INVALID_RX_BANDWIDTH	LITERAL1
+ERR_INVALID_SYNC_WORD	LITERAL1
 
 ERR_AT_FAILED	LITERAL1
 ERR_URL_MALFORMED	LITERAL1

src/TypeDef.h

@@ -67,10 +67,13 @@
 #define ERR_INVALID_OUTPUT_POWER              0x0C
 #define PREAMBLE_DETECTED                     0x0D
 #define CHANNEL_FREE                          0x0E
+
+// RF69-specific status codes
 #define ERR_INVALID_BIT_RATE                  0x0F
 #define ERR_INVALID_FREQUENCY_DEVIATION       0x10
 #define ERR_INVALID_BIT_RATE_BW_RATIO         0x11
 #define ERR_INVALID_RX_BANDWIDTH              0x12
+#define ERR_INVALID_SYNC_WORD                 0x13
 
 // ESP8266 status codes
 #define ERR_AT_FAILED                         0x01

src/modules/RF69.cpp

@@ -72,6 +72,13 @@ uint8_t RF69::begin(float freq, float br, float rxBw, float freqDev, int8_t powe
     return(state);
   }
   
+  // default sync word values 0x2D01 is the same as the default in LowPowerLab RFM69 library
+  uint8_t syncWord[] = {0x2D, 0x01};
+  state = setSyncWord(syncWord, 2);
+  if(state != ERR_NONE) {
+    return(state);
+  }
+  
   return(ERR_NONE);
 }
 
@@ -368,6 +375,41 @@ uint8_t RF69::setOutputPower(int8_t power) {
   return(state);
 }
 
+uint8_t RF69::setSyncWord(uint8_t* syncWord, size_t len, uint8_t maxErrBits) {
+  // check constraints
+  if((maxErrBits > 7) || (len > 8)) {
+    return(ERR_INVALID_SYNC_WORD);
+  }
+  
+  // sync word must not contain value 0x00
+  for(uint8_t i = 0; i < len; i++) {
+    if(syncWord[i] == 0x00) {
+      return(ERR_INVALID_SYNC_WORD);
+    }
+  }
+  
+  // enable sync word recognition
+  uint8_t state = _mod->SPIsetRegValue(RF69_REG_SYNC_CONFIG, RF69_SYNC_ON | RF69_FIFO_FILL_CONDITION_SYNC | (len - 1) << 3 | maxErrBits, 7, 0);
+  if(state != ERR_NONE) {
+    return(state);
+  }
+  
+  // set sync word
+  _mod->SPIwriteRegisterBurst(RF69_REG_SYNC_VALUE_1, syncWord, len);
+  return(ERR_NONE);
+}
+
+uint8_t RF69::setNodeAddress(uint8_t nodeAddr) {
+  // enable address filtering (node only)
+  uint8_t state = _mod->SPIsetRegValue(RF69_REG_PACKET_CONFIG_1, RF69_ADDRESS_FILTERING_NODE, 2, 1);
+  if(state != ERR_NONE) {
+    return(state);
+  }
+  
+  // set node address
+  return(_mod->SPIsetRegValue(RF69_REG_NODE_ADRS, nodeAddr));
+}
+
 uint8_t RF69::config() {
   uint8_t state = ERR_NONE;
 

src/modules/RF69.h

@@ -428,12 +428,13 @@ class RF69 {
     uint8_t sleep();
     uint8_t standby();
     
-    // setting methods
+    // configuration methods
     uint8_t setFrequency(float freq);
     uint8_t setBitRate(float br);
     uint8_t setRxBandwidth(float rxBw);
     uint8_t setFrequencyDeviation(float freqDev);
     uint8_t setOutputPower(int8_t power);
+    uint8_t setSyncWord(uint8_t* syncWord, size_t len, uint8_t maxErrBits = 0);
   
   protected:
     Module* _mod;