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Thread: How do you check if Teensy 2.0 INT6 (pin 24) works?

  1. #1
    Junior Member
    Join Date
    Feb 2019

    How do you check if Teensy 2.0 INT6 (pin 24) works?

    I am currently working on a Teensy 2.0 project that requires me to use the following:
    SS SCLK MOSI MISO (0,1,2,3) - for an Adafruit RFM95W LoRa module -
    SCL SDA (5,6) - for an Adafruit SHT31-D sensor -
    RX TX (7,8) - for an Adafruit PM2.5 Sensor -

    Now for my LoRa module to work, I needed an INT pin and based on the datasheet, pins 5,6,7,8 and 24 are my only choices.
    Now 5, 6, 7 and 8 are already being used and my only choice would be pin 24.

    I have tested each INT pin (5, 6, 7 and 8) on my LoRa module and it works.
    Upon testing pin 24, I can do a digital High/Low on it. But when I use it for my LoRa it won't respond.

    I'm using the RadioHead Library on the Arduino IDE and this is how I setup the pin
    RH_RF95 rf95(0,24); // param1 is SS pin and param2 is the INT pin

    Is there any special setting to make pin 24 work as an INT pin?

  2. #2
    Senior Member+ manitou's Avatar
    Join Date
    Jan 2013
    It appears that Teensy 2 core does not support attachInterrupt() on pin 24. I'll take a look at how hard it will be to fix ....

  3. #3
    Senior Member+ manitou's Avatar
    Join Date
    Jan 2013
    OK, attached is hacked WInterrupts.c Use it to replace hardware/teensy/avr/cores/teensy/WInterrupts.c
    You must call attachInterrupt() with 24 as the pin. (digitalPinToInterrupt(), pin2int(), and detachInterrupt() have NOT been fixed).
    I did a quick test jumpering a PWM pin (analogWrite(10,128)) to pin 24 and counting ticks in the isr function.
    Attached Files Attached Files

  4. #4
    Junior Member
    Join Date
    Feb 2019
    So I tried using "RH_RF95 rf95(0,24)" and it still doesn't work.
    So you mentioned that I should use attachInterrupt(pin,ISR,mode) for it to work properly.
    I'm not using the ISR because RH_RF95 is just a constructor for me to use and i guess it won't be fixed until the whole thing gets sorted out?

    So here's actually how the first part of my code looks like in case you're wondering how I use it:

    #include <LiquidCrystal_I2C.h>
    #include <Wire.h>
    #include <Arduino.h>
    #include <EEPROM.h>
    #include <RHRouter.h>
    #include <RHMesh.h>
    #include <RH_RF95.h>
    #include "Adafruit_SHT31.h"
    #include <AltSoftSerial.h>
    #define N_NODES 2
    uint8_t nodeId;
    uint8_t routes[N_NODES]; // full routing table for mesh
    int16_t rssi[N_NODES]; // signal strength info
    float ppm[12];
    AltSoftSerial pmsSerial;
    Adafruit_SHT31 sht31 = Adafruit_SHT31();
    LiquidCrystal_I2C lcd(0x27, 16, 2);
    // Singleton instance of the radio driver
    RH_RF95 rf95(0,24);
    // Class to manage message delivery and receipt, using the driver declared above
    RHMesh *manager;
    // message buffer
    char buf[120];
    const long interval = 1000;
    unsigned long previousMillis = 0;
    int freeMem() {
      extern int __heap_start, *__brkval;
      int v;
      return (int) &v - (__brkval == 0 ? (int) &__heap_start : (int) __brkval);
    struct pms5003data {
      uint16_t framelen;
      uint16_t pm10_standard, pm25_standard, pm100_standard;
      uint16_t pm10_env, pm25_env, pm100_env;
      uint16_t particles_03um, particles_05um, particles_10um, particles_25um, particles_50um, particles_100um;
      uint16_t unused;
      uint16_t checksum;
    struct pms5003data data;
    void setup(
    manager = new RHMesh(rf95, nodeId);
    // fails initialization when rh95 cannot use pin 24 as intterupt
      if (!manager->init()) {
        Serial.println(F("init failed"));
      } else {
    ) {...}
    void loop() {...}

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