// Thia is the interrupt in respect of the ADXL chip and declared at global scope
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void IRAM_ATTR falling()

{//this is pin 14 connected to interrupt int 1 

       
     mytime = millis();//grab the time and store in global varaible
      GLOBAL_ADXL_FLAG=true;//just set the flag and exit
       detachInterrupt(digitalPinToInterrupt(CFG_PIN));//kill
      //We will let the loop deal with it 
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//
// 
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void IRAM_ATTR WirelessUp()

{//this is pin 13 connected to push button 
 detachInterrupt(digitalPinToInterrupt(WIRE_PIN));//kill
       //WIRELESS_FLAG//THIS IS FLAG TO SET FOR REMOTE ACCESS
    
     Serial.println("interrupt on 13!!!");
      WIRELESS_FLAG=true;//set the flag and exit gets reset in loop
      //We will let the loop deal with it 
}


Note

CFG_PIN and WIRE_PIN were previously declared here

int WIRE_PIN = 13;//change this mapping for remote access and upload
int CFG_PIN = 14;//change this mapping for serial2 on 16


//now in setup attach them to the pins

 pinMode(WIRE_PIN, INPUT_PULLUP);//cfg pin will be pin 13 to catch the interrupt for remote
 attachInterrupt(digitalPinToInterrupt(WIRE_PIN), WirelessUp, FALLING);//function is called WirelessUp
  pinMode(CFG_PIN, INPUT_PULLUP);//cfg pin will be pin 14 to catch the interrupt
  attachInterrupt(digitalPinToInterrupt(CFG_PIN), falling, FALLING);//function is called falling




 GLOBAL_ADXL_FLAG and  WIRELESS_FLAG were also declared previously as bools

bool GLOBAL_ADXL_FLAG=0;//interrupt for adxl
bool WIRELESS_FLAG=0;//INTERRUPT FOR REMOTE ACCESS

Note the use of void IRAM_ATTR  to make sure these remain static and unaltered.



In main we deal with it like so:


if(WIRELESS_FLAG==true)//test this flag
{
  stopgps=true;//stop the gps func
   Serial.println("stoppedGPS!!");
   altstatus=false;
   satstatus=false;
   speedstatus=false;
   latlong=false;//disable the saving of details on disk when gps stopped
   WiFi.mode(WIFI_OFF);
  delay(2000);//wait a bit
  WiFi.begin();

// do other stuff


//and for the ADXL interrupt


 if(GLOBAL_ADXL_FLAG==true)//interrupt triggered for some reason

  {
    I2CiSbUSY=true;
    GLOBAL_ADXL_FLAG=false;//reset it
     writeToI2C(ADXL345_DEVICE,ADXL345_INT_ENABLE  ,0x00);//disable the interrupts
    
    readFromI2C(ADXL345_DEVICE,ADXL345_INT_SOURCE,1,&interrupt_byte);//find out the source
     Serial.print("status interrupt=  ");
      Serial.println(interrupt_byte,HEX);

    testbyte=interrupt_byte & MASK_TAP;
     if(testbyte)
        {

           Serial.println("*** BIG SHOCK DETECTED!!***");
          display.setCursor(0,0);
               display.clearDisplay();
              display.display();
                display.print("BIG SHOCK DETECTED!!");
                display.display();
                 
      
      display.setCursor(0,20);
     display.print("OOH THAT HURT!!");
     display.display();
              //delay(1000);

            WriteShockData();
           listDir(SD, "/", 0);
            writeToI2C(ADXL345_DEVICE,ADXL345_INT_ENABLE  ,0x48);//reenable the interrupts after flag set regardless
    // attachInterrupt(digitalPinToInterrupt(CFG_PIN), falling, FALLING);//function is called falling
          I2CiSbUSY=false;//start the display
        }//the type of interrupt


//note also the use of detach interrupt to stop further interrupts while servicing