kx134-1211 how to change the ODR?

Sensors IMU & Motion
1

I would like to set the ODR in the sensor but when I add the call setOutputDataRate() with any parameter between 0 and 15 the accelerometer reading never changes. I tried it for different calls to setRange() not still doesn’t work.

Any idea where to start?

2

There’s a bug in the file SparkFun_Qwiic_KX13X.cpp. I have updated setOutputDataRate(uint8_t rate) to take care of it.

Before the fix, any call to the function caused the sensor to never be ready to be read.

//Address: 0x21, bits[3:0] - default value is 0x06 (50Hz)
//Sets the refresh rate of the accelerometer's data. 
// 0.781 * (2 * (n)) derived from pg. 26 of Technical Reference Manual  <----incorrect expression

bool QwiicKX13xCore::setOutputDataRate(uint8_t rate){

  if( rate < 0 | rate > 15 )
    return false;

  uint8_t accelState = readAccelState(); // Put it back where we found it.
  accelControl(false); // Can't adjust without putting to sleep

  KX13X_STATUS_t returnError;
  returnError = writeRegister(KX13X_ODCNTL, 0xF0, rate, 0);
  if( returnError == KX13X_SUCCESS ) {
	accelControl(accelState);                   // added this to fix the ERROR
    return true;
  }
  else 
    return false;

    // if( returnError == KX13X_SUCCESS ){     // These lines should be removed.
    // accelControl(accelState);
    // return true;
    // }
    // else
    // return false;
}

In addition, the function readOutputDataRate() was calculating the ODR in Hz incorrectly. It was calculating

0.781 * (2 * (n))
``` instead of ```
0.781 * pow(2, n)

Please check the code below:

// Address:0x21 , bit[3:0]: default value is: 0x06 (50Hz)
// Gets the accelerometer's output data rate. 
float QwiicKX13xCore::readOutputDataRate(){
  
  uint8_t tempRegVal;
  readRegister(&tempRegVal, KX13X_ODCNTL);
  tempRegVal &= 0x0F;
  tempRegVal = (float)tempRegVal;
  return (0.781 * pow(2, tempRegVal));

}

A.