raspberry pico w, RFM98W, one sent message causes two received interrupts

[8rogos]

hello,

I'm trying to receive a message between two systems:

• raspberry pico w with SDK
• RFM98W REV:1.2 433MHz

I use SX127x Class. When I send one message, the code below sees two interrupts, even though the RFM module on the DI00 pin sends one peak

define SPI_PORT spi0
#define SPI_MISO 16
#define SPI_MOSI 19
#define SPI_SCK 18

#define RFM_NSS 17
#define RFM_RST 20
#define RFM_DIO0 21
#define RFM_DIO1 22

#include <pico/stdlib.h>

// include the library
#include <RadioLib.h>

// include the hardware abstraction layer
#include "PicoHal.h"


// create a new instance of the HAL class
PicoHal* hal = new PicoHal(SPI_PORT, SPI_MISO, SPI_MOSI, SPI_SCK);

// now we can create the radio module
SX1278 radio = new Module(hal, RFM_NSS, RFM_DIO0, RFM_RST, RFM_DIO1);

volatile bool receivedFlag = false;
int inter{0};

void setFlag(void)
{
  // we got a packet, set the flag
  inter++;
  receivedFlag = true;
  printf("Innterupt number: %i \n", inter);
}


int main() 
{ 
  // initialize just like with Arduino
  printf("[SX1278] Initializing ... ");
  int state = radio.begin(433.0);
  if (state != RADIOLIB_ERR_NONE) {
    printf("failed, code %d\n", state);
    return(1);
  }
  printf("success!\n");

  radio.setPacketReceivedAction(setFlag);
  
  // start listening for LoRa packets
  printf("[SX1278] Starting to listen ... ");
  state = radio.startReceive();

  if (state != RADIOLIB_ERR_NONE) {
    printf("failed, code %d\n", state);
    return(1);
  }
  printf("success!\n");


  while(true)
  {
    // check if the flag is set
    if(receivedFlag) 
    {
      // reset flag
      receivedFlag = false;

      unsigned char byteArr[255];
      int numBytes = radio.getPacketLength();

      int state = radio.readData(byteArr, numBytes);
    

      if (state == RADIOLIB_ERR_NONE)
      {
        // packet was successfully received
        printf("[SX1278] Received packet!\n");
        /*
        // print data of the packet
        char str[(sizeof byteArr) + 1];
        memcpy(str, byteArr, sizeof byteArr);
        str[sizeof byteArr] = 0; // Null termination.
        */

        printf("[SX1278] Data:");
        printf("%s\n", byteArr);

        // print RSSI (Received Signal Strength Indicator)
        printf("[SX1278] RSSI:\t\t");
        printf("%f dbm\n",radio.getRSSI());


        // print SNR (Signal-to-Noise Ratio)
        printf("[SX1278] SNR:\t\t");
        printf("%d dbm\n", radio.getSNR());

        // print frequency error
        printf("[SX1278] Frequency error:\t");
        printf("%f Hz\n", radio.getFrequencyError());

      } 
      else if (state == RADIOLIB_ERR_CRC_MISMATCH)
      {
        // packet was received, but is malformed
        printf("[SX1278] CRC error!");

      } else 
      {
        // some other error occurred
        printf("[SX1278] Failed, code ");
        printf("failed, code %d\n", state);

      }
    }
  }
  return(0);
}

Innterupt number: 285 Innterupt number: 286 [SX1278] Received packet! [SX1278] Data:L3 [SX1278] RSSI:-74.000000 dbm [SX1278] SNR:1076396032 dbm [SX1278] Frequency error:1415.577637 Hz [SX1278] Received packet! [SX1278] Data:L3 [SX1278] RSSI:-74.000000 dbm [SX1278] SNR:1076396032 dbm [SX1278] Frequency error:1415.577637 Hz Innterupt number: 287 Innterupt number: 288 [SX1278] Received packet! [SX1278] Data:L3 [SX1278] RSSI:-65.000000 dbm [SX1278] SNR:1076330496 dbm [SX1278] Frequency error:1407.188965 Hz [SX1278] Received packet! [SX1278] Data:L3 [SX1278] RSSI:-65.000000 dbm [SX1278] SNR:1076330496 dbm [SX1278] Frequency error:1407.188965 Hz

[jgromes]

Are you sure that printing from inside ISR is safe on Raspberry Pico? Try removing that print statement and only printing from inside the main loop. Also inter shoud probably be volatile since it's getting modified from an ISR.

[8rogos]

i'm not sure if it's safe, but it's the same with or without print in ISR. I still need to verify the electrical connection to DIO1, I think it may be bad.

Edit: I checked the electrical connections and everything is OK, I removed the print from the ISR and I still get two ISR calls for one message.

[8rogos]

I also tried clearing the events manually but it doesn't help, still the ISR function is called 2 times for each interrupt:

gpio_acknowledge_irq(RFM_DIO0, GPIO_IRQ_EDGE_RISE | GPIO_IRQ_EDGE_FALL);