Merge with Wi6Labs Pull Request and add X-NUCLEO examples

Author: cparata

README.md

@@ -1,2 +1,31 @@
 # HTS221
 Arduino library to support the HTS221 capacitive digital sensor for relative humidity and temperature
+
+## API
+
+This sensor uses I2C to communicate. It is then required to create a TwoWire interface before accessing to the sensors:  
+
+  dev_i2c = new TwoWire(I2C2_SDA, I2C2_SCL);  
+  dev_i2c->begin();  
+
+An instance can be created and enbaled following the procedure below:  
+
+  For the humidity sensor:  
+
+    HumTemp = new HTS221Sensor (dev_i2c);  
+    HumTemp->Enable();  
+
+The access to the sensor values is done as explained below:  
+
+  Read humidity and temperature.  
+
+    HumTemp->GetHumidity(&humidity);  
+    HumTemp->GetTemperature(&temperature);  
+
+## Documentation
+
+You can find the source files at  
+https://github.com/stm32duino/HTS221
+
+The HTS221 datasheet is available at  
+http://www.st.com/content/st_com/en/products/mems-and-sensors/humidity-sensors/hts221.html