/*
   http://www.dauxi.com/KS10X-V110_EN.pdf

   11101000
   https://www.arduino.cc/en/Tutorial/SFRRangerReader


*/
#include <M5Stack.h>
#include <Wire.h>

#define KS103ADD  0x74 // questo è quello che da lo scanner IIC
//#define KS103ADD  0xE8 // questo è quello che da all'inizio il led verde 11101000    back green led Short flash twice will be “1”, slow flash once will be “0”
word dist = 0;
void setup()
{
  Wire.begin();
//    Wire.begin(22, 21);//M5STACK: 22/SCL/GIALLO ,21/SDA/BIANCO
  Serial.begin(115200);
  //inizio comando
  Wire.beginTransmission(KS103ADD);
  Wire.write(byte(0x02));
  Wire.write(0x72);   // Invia istruzioni per la riduzione del rumore
  Wire.endTransmission();
  // fine comando
  delay(2000);
}
void loop()
{
  // if (Serial.read() == 's') {
  //  while (Serial.read() != 'o') {
  KS103_read();
  Serial.print(dist/10);
  Serial.print(" cm");
  Serial.println();
  delay(250);
  //}
  //}
  // delay(1000);
}

void KS103_read() {
  // step 1: instruct sensor to read echoes
  Wire.beginTransmission(KS103ADD);  // transmit to device
  // the address specified in the datasheet is (0xE8)
  // but i2c adressing uses the high 7 bits so it's  (0x74)
  Wire.write(byte(0x02)); // sets register pointer to echo #1 register (0x02)
  Wire.write(0xbc);     //Range is set to 10m with temperature compensation
  Wire.endTransmission();

  // step 2: wait for readings to happen
  //  delay(1);
  delay(70);   // datasheet suggests at least 65 milliseconds

  // step 3: instruct sensor to return a particular echo reading
  Wire.beginTransmission(KS103ADD);  // transmit to device 
  Wire.write(byte(0x02));  // sets register pointer to echo #1 register (0x02)
  Wire.endTransmission();  // stop transmitting

  // step 4: request reading from sensor
  Wire.requestFrom(KS103ADD, 2);  // request 2 bytes from slave device

  // step 5: receive reading from sensor
  if (2 <= Wire.available()) // if two bytes were received
  {
    dist = Wire.read(); // receive high byte (overwrites previous reading)
    dist =  dist << 8;  // shift high byte to be high 8 bits
    dist |= Wire.read(); // receive low byte as lower 8 bits
  }
}