Microchip RN-2903 pear to pear communication

End Devices (Nodes) Hardware
1

We are trying to connect two Lora modules but we are not getting RX

Send TX By This code

#include <SoftwareSerial.h>

SoftwareSerial loraSerial(10, 11);

String str;

void setup() {
  //output LED pin
  pinMode(13, OUTPUT);
  led_off();
  
  // Open serial communications and wait for port to open:
  
  Serial.begin(9600);
  
  loraSerial.begin(115200);
  loraSerial.setTimeout(1000);
  lora_autobaud();
  
  led_on();
  delay(1000);
  led_off();

  Serial.println("Initing LoRa");
  
  loraSerial.listen();
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  loraSerial.println("sys get ver");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("mac pause");     // Activates P2P transmission between the modules 
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
//  loraSerial.println("radio set bt 0.5");
//  wait_for_ok();
  
  loraSerial.println("radio set mod lora");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set freq 865100000");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set pwr 14");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set sf sf7");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set afcbw 41.7");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set rxbw 125");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
//  loraSerial.println("radio set bitrate 50000");
//  wait_for_ok();
  
//  loraSerial.println("radio set fdev 25000");
//  wait_for_ok();
  
  loraSerial.println("radio set prlen 8");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set crc on");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set iqi off");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set cr 4/5");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set wdt 60000"); //disable for continuous reception
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set sync 12");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set bw 125");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);

  Serial.println("starting loop");
}

void loop() {
  led_on();
    

  loraSerial.println("radio tx 3031"); 		
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  led_off();
  delay(2000);
}

void lora_autobaud()
{
  String response = "";
  while (response=="")
  {
    delay(1000);
    loraSerial.write((byte)0x00);
    loraSerial.write(0x55);
    loraSerial.println();
    loraSerial.println("sys get ver");
    response = loraSerial.readStringUntil('\n');
  }
}

/*
 * This function blocks until the word "ok\n" is received on the UART,
 * or until a timeout of 3*5 seconds.
 */
int wait_for_ok()
{
  str = loraSerial.readStringUntil('\n');
  if ( str.indexOf("ok") == 0 ) {
    return 1;
  }
  else return 0;
}

void led_on()
{
  digitalWrite(13, 1);
}

void led_off()
{
  digitalWrite(13, 0);
}

RX Code
Wating For RX

#include <SoftwareSerial.h>

SoftwareSerial loraSerial(10, 11);

String str;
char e  ;

void setup() {
  //output LED pin
  pinMode(13, OUTPUT);
  //led_off();
  
  // Open serial communications and wait for port to open:
  
  Serial.begin(9600);
  
  loraSerial.begin(115200);
  loraSerial.setTimeout(1000);
  lora_autobaud();
  
  led_on();
  delay(1000);
  led_off();

  Serial.println("Initing LoRa");
  
  loraSerial.listen();
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  loraSerial.println("sys get ver");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("mac pause");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set bt 0.5");
 wait_for_ok();
  
  loraSerial.println("radio set mod lora");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set freq 865100000");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set pwr 14");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set sf sf7");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set afcbw 41.7");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set rxbw 125");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set bitrate 50000");
wait_for_ok();
  
 loraSerial.println("radio set fdev 25000");
 wait_for_ok();
  
  loraSerial.println("radio set prlen 8");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set crc on");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set iqi off");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set cr 4/5");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set wdt 0"); //disable for continuous reception
 str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set sync 12");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
  
  loraSerial.println("radio set bw 125");
  str = loraSerial.readStringUntil('\n');
  Serial.println(str);
}

void loop() {
  //Serial.println("waiting for a message");
  loraSerial.println("radio rx 0"); //continous reception
 
  str = loraSerial.readStringUntil('\n');
  if ( str.indexOf("ok") == 0 )
  {
    str = String("");
    while(str=="")
    {
 
      str = loraSerial.readStringUntil('\n');
    }
    if ( str.indexOf("radio_rx") == 0 ) {

          Serial.print("packet: ");
         Serial.println(e);

      toggle_led();
    }
    else
    {
      Serial.println("Received nothing");
    }


  }
  else
  {
    Serial.println("radio not going into receive mode");
    delay(1000);
  }

 
}
void lora_autobaud()
{
  String response = "";
  while (response=="")
  {
    delay(1000);
    loraSerial.write((byte)0x00);
    loraSerial.write(0x55);
    loraSerial.println();
    loraSerial.println("sys get ver");
    response = loraSerial.readStringUntil('\n');
  }
}

/*
 * This function blocks until the word "ok\n" is received on the UART,
 * or until a timeout of 3*5 seconds.
 */
int wait_for_ok()
{
  str = loraSerial.readStringUntil('\n');
  if ( str.indexOf("ok") == 0 ) {
    return 1;
  }
  else return 0;
}

void toggle_led()
{
  digitalWrite(13, !digitalRead(13));
}

void led_on()
{
  digitalWrite(13, 1);
}

void led_off()
{
  digitalWrite(13, 0);
}
2

I would doubt whether anyone in the TTN forum has tried to use the RN2903 for non TTN applications.

Point to Point applications are outside the scope of TTN.

3

It’s problem if you know solution help if you don’t know find but don’t misguide.

4

How is your question related to TTN ?

5

LoRaTracker is right. The TTN forum is about LoRaWAN, not plain LoRa. Don’t expect answers to your question here. Have you tried the Microchip forum?

6

I use the RN-2903 in peer to peer mode. It works well.

I have not studied your code but the most obvious standout is you are configuring the radio for the EU frequencies (“radio set freq 865100000”) instead of the 915MHz you should be using.

1 Like
7

Haven’t tried it, but the Sodaq boards use the RN chips - one of their examples may help you

https://support.sodaq.com/Boards/ExpLoRer/Examples/lora_p2p/

1 Like