Unable to get accurate values with ADXL359z

Using Arduino Sensors
1

I am working on getting vibration data from ADXL359z accelerometer but the data that i get is wrong. I using EVAL-ADXL359z with raspberry pi 4 model B and fetching data via SPI.
So when i fetch the raw values for all 3 axis and keep any 1 axis inline with earths gravity, that value should be stagnant and other 2 axis should show change but all 3 axis values change in a very adhoc manner.
Below is the Arduino code i am using to fetch the data,, it is library for ADXL355 but both the sensor are pin to pin compatible and have same registers.
Also what formula should i use to convert the raw data into g.

/*
ADXL355-PMDZ Accelerometer Sensor Display

Shows the output of a ADXL355 accelerometer.
Uses the SPI library. For details on the sensor, see:
ADXL355 Low Noise, Programmable ±2g, ±4g, and ±8g Accelerometer PMOD [Analog Devices Wiki]

Created 22 June 2018
by Gabriel Vidal
*/

#include <SPI.h>

// Memory register addresses:
const int XDATA3 = 0x08;
const int XDATA2 = 0x09;
const int XDATA1 = 0x0A;
const int YDATA3 = 0x0B;
const int YDATA2 = 0x0C;
const int YDATA1 = 0x0D;
const int ZDATA3 = 0x0E;
const int ZDATA2 = 0x0F;
const int ZDATA1 = 0x10;
const int RANGE = 0x2C;
const int POWER_CTL = 0x2D;
const int REG_RESET = 0x2F;
const int REG_DEVID_AD = 0x00 ;   // 0xAD
const int REG_DEVID_MST = 0x01 ;  // 0x1D
const int REG_PART_ID = 0x02    ; // 0xE9
const int REG_REVID = 0x03       ;// 0x01
const int REG_STATUS = 0x04;

// Device values  
const int RANGE_10G = 0x01;
const int RANGE_20G = 0x02;
const int RANGE_40G = 0x03;
const int MEASURE_MODE = 0x06; // Only accelerometer

// Operations
const int READ_BYTE = 0x01;
const int WRITE_BYTE = 0x00;

// Pins used for the connection with the sensor
const int CHIP_SELECT_PIN = 53;

void setup() {
  Serial.begin(9600);
  SPI.begin();

  // Initalize the  data ready and chip select pins:
  pinMode(CHIP_SELECT_PIN, OUTPUT);

  //Configure ADXL359:
  writeRegister(RANGE, RANGE_10G); // 10G
  writeRegister(POWER_CTL, MEASURE_MODE); // Enable measure mode

  // Give the sensor time to set up:
  delay(100);
}

void loop() {
  int axisAddresses[] = {XDATA1, XDATA2, XDATA3, YDATA1, YDATA2, YDATA3, ZDATA1, ZDATA2, ZDATA3};
  int axisMeasures[] = {0, 0, 0, 0, 0, 0, 0, 0, 0};
  int dataSize = 9;

  // Read accelerometer data
  readMultipleData(axisAddresses, dataSize, axisMeasures);

  // Split data
  int xdata = (axisMeasures[0] >> 4) + (axisMeasures[1] << 4) + (axisMeasures[2] << 12);
  int ydata = (axisMeasures[3] >> 4) + (axisMeasures[4] << 4) + (axisMeasures[5] << 12);
  int zdata = (axisMeasures[6] >> 4) + (axisMeasures[7] << 4) + (axisMeasures[8] << 12);
  
  // Apply two complement
  if (xdata >= 0x80000) {
    xdata = ~xdata + 1;
  }
  if (ydata >= 0x80000) {
    ydata = ~ydata + 1;
  }
  if (zdata >= 0x80000) {
    zdata = ~zdata + 1;
  }

  // Print axis
  Serial.print("X=");
  Serial.print(xdata);
  Serial.print("\t");
  
  Serial.print("Y=");
  Serial.print(ydata);
  Serial.print("\t");

  Serial.print("Z=");
  Serial.print(zdata);
  Serial.print("\n");

  
  // Next data in 100 milliseconds
  delay(100);
}

/* 
 * Write registry in specific device address
 */
void writeRegister(byte thisRegister, byte thisValue) {
  byte dataToSend = (thisRegister << 1) | WRITE_BYTE;
  digitalWrite(CHIP_SELECT_PIN, LOW);
  SPI.transfer(dataToSend);
  SPI.transfer(thisValue);
  digitalWrite(CHIP_SELECT_PIN, HIGH);
}

/* 
 * Read registry in specific device address
 */
unsigned int readRegistry(byte thisRegister) {
  unsigned int result = 0;
  byte dataToSend = (thisRegister << 1) | READ_BYTE;

  digitalWrite(CHIP_SELECT_PIN, LOW);
  SPI.transfer(dataToSend);
  result = SPI.transfer(0x00);
  digitalWrite(CHIP_SELECT_PIN, HIGH);
  return result;
}

/* 
 * Read multiple registries
 */
void readMultipleData(int *addresses, int dataSize, int *readedData) {
  digitalWrite(CHIP_SELECT_PIN, LOW);
  for(int i = 0; i < dataSize; i = i + 1) {
    byte dataToSend = (addresses[i] << 1) | READ_BYTE;
    SPI.transfer(dataToSend);
    readedData[i] = SPI.transfer(0x00);
  }
  digitalWrite(CHIP_SELECT_PIN, HIGH);
}

have been at it for some time and couldn't figure out the issue.
Any help would be much appreciated.

thanks in advance

2

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