RFM69 not initialising (required reset could be the cause)

  • Hi,
    I'm having issues getting my RFM69HCW to work with MySensors.
    If I try a bare bones setup with the RFM69 library directly it also failed, until I found a helpful post suggesting resetting the radio before starting.
    So once I added a wire for the reset pin and pulsed it high->low in setup it all started working flawlessly!

    pinMode(RFM69_RST_PIN, OUTPUT);
    digitalWrite(RFM69_RST_PIN, HIGH);
    digitalWrite(RFM69_RST_PIN, LOW);

    So now I'm wondering if something similar is required in MySensors to get this to work ?
    I tried adding the same block into the my MySensors code but it still fails when trying to initialise the transport

    0;255;3;0;9;MCO:BGN:INIT GW,CP=RRNGA--,VER=2.2.0-beta
    0;255;3;0;9;!TSM:INIT:TSP FAIL

    Thanks guys

  • Hardware Contributor


    looks strange.
    Actually you don't need to reset the rfm69 with Mysensors nor Lowpowerlab libs. But that will be an upcoming, optional feature in the next driver.

    What's your hardware and sketch?

  • Hey,

    The Hardware I'm using is an Arduino Pro mini (3.3v) and an RFM69HCW on the Adafruit breakout board.

    The LPL sketch that works is below, as for the MySensors one It's basically just the examples (as a serial gateway and node) that won't work.

    // Sample RFM69 sender/node sketch, with ACK and optional encryption, and Automatic Transmission Control
    // Sends periodic messages of increasing length to gateway (id=1)
    // It also looks for an onboard FLASH chip, if present
    // **********************************************************************************
    // Copyright Felix Rusu 2016, http://www.LowPowerLab.com/contact
    // **********************************************************************************
    // License
    // **********************************************************************************
    // This program is free software; you can redistribute it
    // and/or modify it under the terms of the GNU General
    // Public License as published by the Free Software
    // Foundation; either version 3 of the License, or
    // (at your option) any later version.
    // This program is distributed in the hope that it will
    // be useful, but WITHOUT ANY WARRANTY; without even the
    // implied warranty of MERCHANTABILITY or FITNESS FOR A
    // PARTICULAR PURPOSE. See the GNU General Public
    // License for more details.
    // Licence can be viewed at
    // http://www.gnu.org/licenses/gpl-3.0.txt
    // Please maintain this license information along with authorship
    // and copyright notices in any redistribution of this code
    // **********************************************************************************
    #include <RFM69.h>         //get it here: https://www.github.com/lowpowerlab/rfm69
    #include <RFM69_ATC.h>     //get it here: https://www.github.com/lowpowerlab/rfm69
    //#include <SPIFlash.h>      //get it here: https://www.github.com/lowpowerlab/spiflash
    #include <SPI.h>           //included with Arduino IDE install (www.arduino.cc)
    #define NODEID        2    //must be unique for each node on same network (range up to 254, 255 is used for broadcast)
    #define NETWORKID     100  //the same on all nodes that talk to each other (range up to 255)
    #define GATEWAYID     1
    //Match frequency to the hardware version of the radio on your Moteino (uncomment one):
    #define FREQUENCY   RF69_433MHZ
    //#define FREQUENCY   RF69_868MHZ
    //#define FREQUENCY     RF69_915MHZ
    #define ENCRYPTKEY    "sampleEncryptKey" //exactly the same 16 characters/bytes on all nodes!
    #define IS_RFM69HW    //uncomment only for RFM69HW! Leave out if you have RFM69W!
    //Auto Transmission Control - dials down transmit power to save battery
    //Usually you do not need to always transmit at max output power
    //By reducing TX power even a little you save a significant amount of battery power
    //This setting enables this gateway to work with remote nodes that have ATC enabled to
    //dial their power down to only the required level (ATC_RSSI)
    //#define ENABLE_ATC    //comment out this line to disable AUTO TRANSMISSION CONTROL
    // #define ATC_RSSI      -80
    #ifdef __AVR_ATmega1284P__
      #define LED           15 // Moteino MEGAs have LEDs on D15
      #define FLASH_SS      23 // and FLASH SS on D23
      #define LED           9 // Moteinos have LEDs on D9
      #define FLASH_SS      8 // and FLASH SS on D8
    #define SERIAL_BAUD   38400
    int TRANSMITPERIOD = 200; //transmit a packet to gateway so often (in ms)
    char payload[] = "123 ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    char buff[20];
    byte sendSize=0;
    boolean requestACK = false;
    // SPIFlash flash(FLASH_SS, 0xEF30); //EF30 for 4mbit  Windbond chip (W25X40CL)
    #ifdef ENABLE_ATC
      RFM69_ATC radio;
      RFM69 radio;
    void setup() {
      pinMode(5, OUTPUT);
      digitalWrite(5, HIGH);
      digitalWrite(5, LOW);
    #ifdef IS_RFM69HW
      radio.setHighPower(); //uncomment only for RFM69HW!
      //radio.setFrequency(919000000); //set frequency to some custom frequency
    //Auto Transmission Control - dials down transmit power to save battery (-100 is the noise floor, -90 is still pretty good)
    //For indoor nodes that are pretty static and at pretty stable temperatures (like a MotionMote) -90dBm is quite safe
    //For more variable nodes that can expect to move or experience larger temp drifts a lower margin like -70 to -80 would probably be better
    //Always test your ATC mote in the edge cases in your own environment to ensure ATC will perform as you expect
    #ifdef ENABLE_ATC
      char buff[50];
      sprintf(buff, "\nTransmitting at %d Mhz...", FREQUENCY==RF69_433MHZ ? 433 : FREQUENCY==RF69_868MHZ ? 868 : 915);
    #ifdef ENABLE_ATC
      Serial.println("RFM69_ATC Enabled (Auto Transmission Control)\n");
    long lastPeriod = 0;
    void loop() {
      //process any serial input
      if (Serial.available() > 0)
        char input = Serial.read();
        if (input >= 48 && input <= 57) //[0,9]
          TRANSMITPERIOD = 100 * (input-48);
          if (TRANSMITPERIOD == 0) TRANSMITPERIOD = 1000;
          Serial.print("\nChanging delay to ");
        if (input == 'r') //d=dump register values
        //if (input == 'E') //E=enable encryption
        //  radio.encrypt(KEY);
        //if (input == 'e') //e=disable encryption
        //  radio.encrypt(null);
      //check for any received packets
      if (radio.receiveDone())
        Serial.print('[');Serial.print(radio.SENDERID, DEC);Serial.print("] ");
        for (byte i = 0; i < radio.DATALEN; i++)
        Serial.print("   [RX_RSSI:");Serial.print(radio.RSSI);Serial.print("]");
        if (radio.ACKRequested())
          Serial.print(" - ACK sent");
      int currPeriod = millis()/TRANSMITPERIOD;
      if (currPeriod != lastPeriod)
      Serial.print("]: ");
      for(byte i = 0; i < sendSize; i++)
      if (radio.sendWithRetry(GATEWAYID, payload, sendSize))
      Serial.print(" ok!");
      else Serial.print(" nothing...");
        sendSize = (sendSize + 1) % 31;

  • So I've managed to now get it working by editing the RFM69 transport as such:


    bool transportInit(void)
    +    // Reset the RFM69 Radio
    +    pinMode(5, OUTPUT);
    +    digitalWrite(5, HIGH);
    +    delay(100);
    +    digitalWrite(5, LOW);
    +    delay(100);
        // Start up the radio library (_address will be set later by the MySensors library)
        if (_radio.initialize(MY_RFM69_FREQUENCY, _address, MY_RFM69_NETWORKID)) {

    Once those lines to reset it were added it works flawlessly every time now 😕
    The adafruit breakout has a pull-high on the RST pin and as far as I'm aware reading the RFM69 datasheet, it does a power on reset also, so I'm not sure why this is neccessary.

  • Hardware Contributor

    oki. so the pullup was keeping it high.
    you can try to put it in your sketch instead of the lib. no need of 100ms. from datasheet it's 100us
    Try in preHwInit(), or in before() . This should work

    void preHwInit(void)
      // Reset the RFM69 Radio
      pinMode(5, OUTPUT);
      digitalWrite(5, HIGH);
      digitalWrite(5, LOW);
      // wait until chip ready

  • Yep that did it, removed the lines from the transport and put them in before() and it's now working like a charm.

    Kind of interesting how this has only seemingly affected me and none of the other many users of the RFM69 😕

    Thanks for the help and pointing me in the right direction scalz!

  • I had the same issue today with a RFM69HW connected to a Wemos D1 Mini. The above solution worked, thank you so much. I had no idea what was going on.
    I also have a RFM69W connected to a generic ESP12-E and with the same code I didn't need to reset. Seems to be hardware related.

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