diff --git a/api/mraa/aio.h b/api/mraa/aio.h
index 23c0857..640eadb 100644
--- a/api/mraa/aio.h
+++ b/api/mraa/aio.h
@@ -51,7 +51,9 @@ extern "C" {
 typedef struct _aio* mraa_aio_context;
 
 /**
- * Initialise an Analog input device, connected to the specified pin
+ * Initialise an Analog input device, connected to the specified pin. Aio pins
+ * are always 0 indexed reguardless of their position. Check your board mapping
+ * for details. An arduino style layout will have A0 as pin14 but AIO0.
  *
  * @param pin Channel number to read ADC inputs
  * @returns aio context or NULL
diff --git a/api/mraa/aio.hpp b/api/mraa/aio.hpp
index 38ea8bc..5404739 100644
--- a/api/mraa/aio.hpp
+++ b/api/mraa/aio.hpp
@@ -56,7 +56,9 @@ class Aio
     }
     /**
      * Aio Constructor, takes a pointer to the AIO context and initialises
-     * the AIO class
+     * the AIO class. Aio pins are always 0 indexed reguardless of their
+     * position. Check your board mapping for details. An arduino style layout
+     * will have A0 as pin14 but AIO0.
      *
      * @param void * to an AIO context
      */