OK! Please execute the following program; it will indicate if your slave device is responding to I2C Bus commands or not. I assume that you have a UNO or a UNO compatible host controller. Please, tell if the Serial Monitor is reporting 0 or not; 0 means -- the sensor is responding to its address 25; non-zero/no-value means -- the sensor is not responding!
#include <Wire.h>
#include "SparkFunISL29125.h"
byte busStatus;
// Declare sensor object
SFE_ISL29125 RGB_sensor;
void setup()
{
// Initialize serial communication
Serial.begin(9600);
Wire.begin();
// Initialize the ISL29125 with simple configuration so it starts sampling
if (RGB_sensor.init())
{
Serial.println("Sensor Initialization Successful\n\r");
}
do
{
Wire.beginTransmission(25); // transmit to device #25
busStatus = Wire.endTransmission();
}
while (busStatus != 0x00);
Serial.println(busStatus, HEX);
}
void loop()
{
}