diff --git a/mjs_fs/api_arduino_htu21df.js b/mjs_fs/api_arduino_htu21df.js
index 51533d0..ae191cf 100644
--- a/mjs_fs/api_arduino_htu21df.js
+++ b/mjs_fs/api_arduino_htu21df.js
@@ -8,31 +8,47 @@ let Adafruit_HTU21DF = {
 
     _proto: {
 
-        // functions
+        // Public functions
+
+        // ## **`myHTU.begin()`**
+        // Initialize sensor and make it ready for use.
+        // Return value: 1 if sensor is ready, 0 otherwise.
         begin: function () {
-            return Adafruit_HTU21DF._begin(this.tsl);
+            return Adafruit_HTU21DF._begin(this.htu);
         },
 
+        // ## **`myHTU.readTemperature()`**
+        // Read the current temperature.
+        // Return value: current temperature value in Celsius as a double.
         readTemperature: function () {
-            return Adafruit_HTU21DF._rdTp(this.tsl);
+            return Adafruit_HTU21DF._rdTp(this.htu);
         },
 
+        // ## **`myHTU.readHumidity()`**
+        // Read the current relative humidity as a percentage.
+        // Return value: current humidity value as a double.
         readHumidity: function () {
-            return Adafruit_HTU21DF._rdHm(this.tsl);
+            return Adafruit_HTU21DF._rdHm(this.htu);
         },
 
+        // ## **`myHTU.reset()`**
+        // Reset the sensor - sends the sensor-specific command to reset.
+        // Return value: none
         reset: function () {
-            Adafruit_HTU21DF._rst(this.tsl);
+            Adafruit_HTU21DF._rst(this.htu);
         }
 
     },
 
+    // ## **`Adafruit_HTU21DF.create()`**
+    // Create an Adafruit_HTU21DF instance on I2C bus (address = 0x40).
+    // Return value: an object with the methods defined in _proto: {...} (above).
     create: function () {
         let obj = Object.create(Adafruit_HTU21DF._proto);
         // set default parameter values
         // Initialize Adafruit_HTU21DF library.
         // Return value: handle opaque pointer.
-        obj.tsl = Adafruit_HTU21DF._create();
+        obj.htu = Adafruit_HTU21DF._create();
         return obj;
     }