Add support for SHTC3 temperature and humidity i2c sensor

[eugentib]

I modified the code (xsns_14_sht3x.ino) to support the SHTC3 sensor

It's not very elegant, but it works.
This is the modified code

``
/*********************************************************************************************\

• SHT3X - Temperature and Humidy
• I2C Address: 0x44 or 0x45
  *********************************************************************************************/

#define SHT3X_ADDR_GND 0x44 // address pin low (GND)
#define SHT3X_ADDR_VDD 0x45 // address pin high (VDD)
#define SHTC3_ADDR 0x70 // address for shtc3 sensor

uint8_t sht3x_type = 0;
uint8_t sht3x_address;
uint8_t sht3x_addresses[] = { SHT3X_ADDR_GND, SHT3X_ADDR_VDD, SHTC3_ADDR};

bool Sht3xRead(float &t, float &h)
{
unsigned int data[6];

t = NAN;
h = NAN;

if(sht3x_address==SHTC3_ADDR){
Wire.beginTransmission(sht3x_address);
Wire.write(0x35); // Wake from
Wire.write(0x17); // sleep
Wire.endTransmission();
Wire.beginTransmission(sht3x_address);
Wire.write(0x78); // Dissable clock stretching ( I don't think that wire library support clock stretching )
Wire.write(0x66); // High resolution
}else{
Wire.beginTransmission(sht3x_address);
Wire.write(0x2C); // Enable clock stretching
Wire.write(0x06); // High repeatability
}
if (Wire.endTransmission() != 0) { // Stop I2C transmission
return false;
}
delay(20); // Timing verified with logic analyzer (10 is to short)
Wire.requestFrom(sht3x_address, (uint8_t)6); // Request 6 bytes of data
for (int i = 0; i < 6; i++) {
data[i] = Wire.read(); // cTemp msb, cTemp lsb, cTemp crc, humidity msb, humidity lsb, humidity crc
};
t = ConvertTemp((float)((((data[0] << 8) | data[1]) * 175) / 65535.0) - 45);
h = (float)((((data[3] << 8) | data[4]) * 100) / 65535.0);
return (!isnan(t) && !isnan(h));
}

/********************************************************************************************/
`
P.S.
I don't understand why insert code doesn't work...

[arendst]

In next pre-release