Update functions_explained.adoc

Author: dadul96

extras/functions_explained.adoc

@@ -4,6 +4,20 @@ The functions of the library are:
 
 **attach(pin)** -- Attaches a servo motor to an i/o pin. (only **pin 2, 3, 7, 8, 44,** and **45**)
 
-**writeMicroseconds(us)** -- Sets the servo pulse width in microseconds. (usable range between **500**us and **2500**us)
+**attach(pin, min, max)** -- Attaches a servo motor to an i/o pin with a custom lower and upper pulse width limit.
+
+**attach(pin, min, max, defaultPos)** -- Attaches a servo motor to an i/o pin with a custom lower and upper pulse width limit. In addition the starting pulse width of the servo can be set with the defaultPos. This allows the servo to start from a user defined angle instead of the middle position.
 
 **detach()** -- Clears the used registers and stops the output of the attached pin. (**no pin number!**)
+
+**detachAll()** -- Clears the used registers and stops the output of ALL attached pins. (**no pin number!**)
+
+**write(degrees)** -- Sets the servo angle in degrees. (usable range between 0° and 180°)
+
+**writeMicroseconds(us)** -- Sets the servo pulse width in microseconds. (standard usable range between **500**us and **2500**us)
+
+**read()** -- Returns the current angle (in degrees) that gets transmitted to the servo. (return datatype: **int**)
+
+**readMicroseconds()** -- Returns the current angle (in microseconds) that gets transmitted to the servo. (return datatype: **int**)
+
+**attached()** -- Returns **true** if the servo is attached, otherwise the return value is **false**. (return datatype: **bool**)