diff --git a/os/io/hal.dox b/os/io/hal.dox
index ea90d8ff6..77dc49a46 100644
--- a/os/io/hal.dox
+++ b/os/io/hal.dox
@@ -18,13 +18,11 @@
 */
 
 /**
- * @defgroup IO I/O
- * @brief I/O related services.
- * @details This section contains the I/O related services.
- *
- * The I/O subsystem is a collection of device driver portable interfaces and
- * platform dependent implementations.<br>
- * Under ChibiOS/RT a device driver is split in two layers:
+ * @defgroup IO HAL
+ * @brief Hardware Abstraction Layer.
+ * @details Under ChibiOS/RT the set of the various device driver interfaces
+ * is called the HAL subsystem: Hardware Abstraction Layer.<br>
+ * A device driver is usually split in two layers:
  * - High Level Device Driver (<b>HLD</b>). This layer contains the definitions
  *   of the driver's APIs and the platform independent part of the driver.<br>
  *   An HLD is composed by two files:
@@ -41,21 +39,50 @@
  *   - @<driver@>_lld.h, the high level header file. This file is implicitly
  *     included by the HLD header file.
  *   .
+ *   The LLD may be not present in those drivers that do not access the
+ *   hardware directly but through other device drivers, as example the
+ *   @ref MMC_SPI driver uses the @ref SPI and @ref PAL drivers in order
+ *   to implement its functionalities.
  * .
  * <h2>Available Device Drivers</h2>
  * The I/O subsystem currently includes support for:
+ * - @ref HAL.
  * - @ref PAL.
  * - @ref SERIAL.
- * - @ref SPI.
  * - @ref ADC.
+ * - @ref CAN.
  * - @ref MAC.
  * - @ref MII.
  * - @ref MMC_SPI.
+ * - @ref SPI.
  * .
  */
 
 /**
- * @defgroup PAL Ports Abstraction Layer (PAL)
+ * @defgroup HAL HAL Driver
+ * @brief Hardware Abstraction Layer.
+ * @details The HAL driver performs the system initialization and includes
+ * the platform support code shared by the other drivers.
+ *
+ * @ingroup IO
+ */
+
+/**
+ * @defgroup HAL_LLD HAL Low Level Driver
+ * @brief @ref HAL low level driver template.
+ *
+ * @ingroup HAL
+ */
+
+/**
+ * @defgroup HAL_CONF Configuration
+ * @brief @ref HAL Configuration.
+ *
+ * @ingroup HAL
+ */
+
+/**
+ * @defgroup PAL PAL Driver
  * @brief I/O Ports Abstraction Layer
  * @details This module defines an abstract interface for digital I/O ports.
  * Note that most I/O ports functions are just macros. The macros
@@ -191,20 +218,26 @@
  * @dot
   digraph example {
       rankdir="LR";
-      node [shape=circle, fontname=Helvetica, fontsize=8, fixedsize="true", width="0.75", height="0.75"];
+      node [shape=circle, fontname=Helvetica, fontsize=8, fixedsize="true", width="0.8", height="0.8"];
       edge [fontname=Helvetica, fontsize=8];
       uninit [label="ADC_UNINIT", style="bold"];
       stop  [label="ADC_STOP\nLow Power"];
       ready [label="ADC_READY\nClock Enabled"];
-      running [label="ADC_RUNNING\nConverting"];
+      running [label="ADC_RUNNING"];
+      complete [label="ADC_COMPLETE"];
       uninit -> stop [label="adcObjectInit()"];
       stop -> ready [label="adcStart()"];
       ready -> ready [label="adcStart()"];
+      ready -> ready [label="adcWaitConversion()"];
       ready -> stop [label="adcStop()"];
       stop -> stop [label="adcStop()"];
       ready -> running [label="adcStartConversion()"];
       running -> ready [label="adcStopConversion()"];
-      running -> ready [label="End of Conversion"];
+      running -> complete [label="End of Conversion"];
+      complete -> running [label="adcStartConversion()"];
+      complete -> ready [label="adcStopConversion()"];
+      complete -> ready [label="adcWaitConversion()"];
+      complete -> stop [label="adcStop()"];
   }
  * @enddot
  *
@@ -223,6 +256,43 @@
  * @ingroup ADC
  */
 
+/**
+ * @defgroup CAN CAN Driver
+ * @brief Generic ADC Driver.
+ * @details This module implements a generic ADC driver. The driver implements
+ *          a state machine internally:
+ * @dot
+  digraph example {
+      rankdir="LR";
+      node [shape=circle, fontname=Helvetica, fontsize=8, fixedsize="true", width="0.8", height="0.8"];
+      edge [fontname=Helvetica, fontsize=8];
+      uninit [label="CAN_UNINIT", style="bold"];
+      stop  [label="CAN_STOP\nLow Power"];
+      ready [label="CAN_READY\nClock Enabled"];
+      sleep [label="CAN_SLEEP\nLow Power"];
+      uninit -> stop [label="canObjectInit()"];
+      stop -> stop [label="canStop()"];
+      stop -> ready [label="canStart()"];
+      ready -> stop [label="canStop()"];
+      ready -> ready [label="canReceive()\ncanTransmit()"];
+      ready -> ready [label="canStart()"];
+      ready -> sleep [label="canSleep()"];
+      sleep -> sleep [label="canSleep()"];
+      sleep -> ready [label="canWakeup()"];
+      sleep -> ready [label="wakeup event"];
+  }
+ * @enddot
+ *
+ * @ingroup IO
+ */
+
+/**
+ * @defgroup CAN_LLD CAN Low Level Driver
+ * @brief @ref HAL low level driver template.
+ *
+ * @ingroup CAN
+ */
+
 /**
  * @defgroup MAC MAC Driver
  * @brief Generic MAC driver.
diff --git a/os/io/readme.txt b/os/io/readme.txt
index 24aace302..252acaae1 100644
--- a/os/io/readme.txt
+++ b/os/io/readme.txt
@@ -1,4 +1 @@
-ChibiOS/RT I/O abstraction layer, available drivers:
-- PAL. Digital I/O ports abstraction layer.
-- Serial. Buffered, interrupt driven, serial communication driver using OS
-  queues, channels and events.
+ChibiOS/RT HAL code