I would like the sensor values to be updated each 10ms(100Hz) and then run the algorithm and repeat the same process. However, after timing the algorithm it is taking only 2ms, I think the data_ready interrupt is not working as expected. Physical hardware connection is from INT1 of ADXL345 to pin2 of the UNO.

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_ADXL345_U.h>
#include <avr/io.h>
#include <avr/power.h>


#define F_CPU 16000000UL


volatile int sensor_update=0;


//----------------------------------------------------------------------------------------------
//Write to ADXL345 registers
void writeTo(int device, byte address, byte val) {
   Wire.beginTransmission(device); //start transmission to device
   Wire.write(address);        // send register address
   Wire.write(val);        // send value to write
   Wire.endTransmission(); //end transmission
}



//----------------------------------------------------------------------------------------------

/////////////////////////////////////////////////////////////////////////////////////////////

//ISR function
 
  void interrupt(void){
  sensor_update=1;
      
  }
 

//////////////////////////////////////////////////////////////////////////////////////////////////


 
void buzz(int targetPin, long frequency, long length) {
  long delayValue = 1000000/frequency/2; // calculate the delay value between transitions
  //// 1 second's worth of microseconds, divided by the frequency, then split in half since
  //// there are two phases to each cycle
  long numCycles = frequency * length/ 1000; // calculate the number of cycles for proper timing
  //// multiply frequency, which is really cycles per second, by the number of seconds to
  //// get the total number of cycles to produce
  for (long i=0; i < numCycles; i++){ // for the calculated length of time...
    digitalWrite(targetPin,HIGH); // write the buzzer pin high to push out the diaphram
    delayMicroseconds(delayValue); // wait for the calculated delay value
    digitalWrite(targetPin,LOW); // write the buzzer pin low to pull back the diaphram
    delayMicroseconds(delayValue); // wait againf or the calculated delay value
  }
}


/* Assign a unique ID to this sensor at the same time */
Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified(12345);





void setup(void)
{
  if (F_CPU == 16000000) clock_prescale_set(clock_div_1);
  Serial.begin(9600);
  //Serial.println("Accelerometer Test"); Serial.println("");

  pinMode(4, OUTPUT);// buzzer output pin
 
  /* Initialise the sensor */
  if(!accel.begin())
  {
    /* There was a problem detecting the ADXL345 ... check your connections */
    //Serial.println("Ooops, no ADXL345 detected ... Check your wiring!");
    while(1);
  }

  /* Set the range to whatever is appropriate for your project */
  accel.setRange(ADXL345_RANGE_16_G);
  accel.setDataRate(ADXL345_DATARATE_100_HZ);
  // displaySetRange(ADXL345_RANGE_8_G);
  // displaySetRange(ADXL345_RANGE_4_G);
  // displaySetRange(ADXL345_RANGE_2_G);
 
 
 
  //Create an interrupt that will trigger when a tap is detected.
  attachInterrupt(0, interrupt, RISING);
 
  writeTo(0x1D, 0x2E, 0);
  writeTo(0x1D, 0x2F, 0);
  writeTo(0x1D, 0x2E, 128);
  writeTo(0x1D, 0x2F, 127);
 
 

}

void loop(void)
{
 
 
  /* Get a new sensor event */
  interrupt();
 
 
 
  if(sensor_update==1 ){
    //When sensor_update is set to 1 in the ISR,the algorithm process the data from the accelerometer being updated every 10ms(100Hz)
     sensor_update=0;//reset
    
    
  }
 

}

 

After fixing the interrupt call from the loop, the interrupt simply never kicks in now. The enable and map registers are set up correctly,could someone confirm that please.

 

After fixing the interrupt call from the loop, the interrupt simply never kicks in now. The enable and map registers are set up correctly,could someone confirm that please.

after some troubleshooting: putting pin2 as an input doesn't change anything.
testing if the output from ADXL INT1 is toggling with 1Hz output rate with a multimeter give 0V so the problem is coming from the accelerometer, somehow it is not generating anything.

edit: I have changed the device to 0x53 instead of 0x1D and now the LED is always on, still not toggling tough.

 

Page 26 of the ADXL345 seems to suggest that you'd need to read from DATAX, DATAY, and DATAZ to clear the interrupt.

 

the library is doing that for me, ]inside the loop I have

if(sensor_update==1){
sensors_event_t event;
accel.getEvent(&event); 
//call the the magnitude calculation function
mag_calculation(event.acceleration.x,event.acceleration.y,event.acceleration.z); 
// rest of algorithm
sensors_update=0; }