Update Documentation

ChangeLog

@@ -10393,3 +10393,7 @@
 	  signal/sig_timed*.c, timer/timer_settime.c, and wdog/wd_start.c:
 	  Update the type passed to watchdog timer handlers.  Using uint32_t is
 	  a problem for 64-bit machines (2015-05-18).
+	* configs/saml21-xplained:  Add a board build configuration for the
+	  SAML21 Xplained Pro.  Initial commit is just the SAMD20 Xplained Pro
+	  board support with naming changed.  Does not yet build (2015-05-18).
+

Documentation/NuttX.html

@@ -8,7 +8,7 @@
   <tr align="center" bgcolor="#e4e4e4">
     <td>
       <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
-      <p>Last Updated: May 1, 2015</p>
+      <p>Last Updated: May 18, 2015</p>
     </td>
   </tr>
 </table>
@@ -1330,7 +1330,7 @@
       <li><a href="#arm926ejs">ARM926EJS</a> (4)</li>
       <li><a href="#armcortexa5">ARM Cortex-A5</a> (2)</li>
       <li><a href="#armcortexa8">ARM Cortex-A8</a> (1)</li>
-      <li><a href="#armcortexm0">ARM Cortex-M0/M0+</a> (4)</li>
+      <li><a href="#armcortexm0">ARM Cortex-M0/M0+</a> (5)</li>
       <li><a href="#armcortexm3">ARM Cortex-M3</a> (32)</li>
       <li><a href="#armcortexm4">ARM Cortex-M4</a> (20)</li>
       <li><a href="#armcortexm7">ARM Cortex-M7</a> (1)</li>
@@ -1402,6 +1402,7 @@
       <li><a href="#avrat90usbxxx">AVR AT90USB64x and AT90USB6128x</a> <small>(8-bit AVR)</small></li>
       <li><a href="#at32uc3bxxx">AVR32 AT32UC3BXXX</a> <small>(32-bit AVR32)</small></li>
       <li><a href="#at91samd20">Atmel SAMD20</a> <small>(ARM Cortex-M0+)</small></li>
+      <li><a href="#at91saml21">Atmel SAML21</a> <small>(ARM Cortex-M0+)</small></li>
       <li><a href="#at91sam3u">Atmel SAM3U</a> <small>(ARM Cortex-M3)</small></li>
       <li><a href="#at91sam3x">Atmel SAM3X</a> <small>(ARM Cortex-M3)</small></li>
       <li><a href="#at91sam4c">Atmel SAM4C</a> <small>(ARM Cortex-M4)</small></li>
@@ -2229,6 +2230,28 @@ nsh>
     </ul>
   </td>
 </tr>
+<tr>
+  <td><br></td>
+  <td><hr></td>
+</tr>
+<tr>
+  <td><br></td>
+  <td>
+    <p>
+      <a name="at91saml21"><b>Atmel SAML21</b>.</a>
+      The port of NuttX to the Atmel SAML21-Xplained Pro development board.
+      This board features the ATSAML21J18A MCU (Cortex-M0+ with 256KB of FLASH and 32KB of SRAM).
+    </p>
+    <ul>
+      <p>
+        <b>STATUS</b>.
+        This is a work in progress.
+        Initial support for the SAML21 Xplained Pro is expected in the NuttX 7.10 timeframe.
+        Refer to the SAML21 Explained Pro board <a href="http://sourceforge.net/p/nuttx/git/ci/master/tree/nuttx/configs/saml21-xplained/README.txt">README</a> file for further information.
+      </p>
+    </ul>
+  </td>
+</tr>
 
 <tr>
   <td valign="top"><img height="20" width="20" src="favicon.ico"></td>

Documentation/NuttxPortingGuide.html

@@ -12,7 +12,7 @@
       <h1><big><font color="#3c34ec">
         <i>NuttX RTOS Porting Guide</i>
       </font></big></h1>
-      <p>Last Updated: April 1, 2015</p>
+      <p>Last Updated: May 18, 2015</p>
     </td>
   </tr>
 </table>
@@ -2725,6 +2725,8 @@ int up_timer_start(FAR const struct timespec *ts);
   <li><a href="#wdstart">4.3.5.3 wd_start</a></li>
   <li><a href="#wdcancel">4.3.5.4 wd_cancel</a></li>
   <li><a href="#wdgettime">4.3.5.5 wd_gettime</a></li>
+  <li><a href="#wdcallback">4.3.5.6 Watchdog Timer Callback</a></li>
+
 </ul>
 
 <h4><a name="wdcreate">4.3.5.1 wd_create/wd_static</a></h4>
@@ -2927,6 +2929,36 @@ VxWorks provides the following comparable interface:
   means either that wdog is not valid or that the wdog has already expired.
 </p>
 
+<h4><a name="wdcallback">4.3.5.6 Watchdog Timer Callback</a></h4>
+<p>
+  When a watchdog expires, the callback function with this type is called:
+</p>
+<pre>
+    typedef void (*wdentry_t)(int argc, ...);
+</pre>
+<p>
+  Where <code>argc</code> is the number of <code>wdparm_t</code> type arguments that follow.
+</p>
+<p>
+  The arguments are passed as scalar <code>wdparm_t</code> values.  For systems where the <code>sizeof(pointer) &lt; sizeof(uint32_t)</code>, the following union defines the alignment of the pointer within the <code>uint32_t</code>.  For example, the SDCC MCS51 general pointer is 24-bits, but <code>uint32_t</code> is 32-bits (of course).
+</p>
+   We always have <code>sizeof(pointer) <= sizeof(uintptr_t)</code> by definition.
+</p>
+<ul><pre>
+union wdparm_u
+{
+  FAR void     *pvarg; /* The size one generic point */
+  uint32_t      dwarg; /* Big enough for a 32-bit value in any case */
+  uintptr_t     uiarg; /* sizeof(uintptr_t) >= sizeof(pointer) */
+};
+
+#if UINTPTR_MAX >= UINT32_MAX
+typedef uintptr_t wdparm_t;
+#else
+typedef uint32_t  wdparm_t;
+#endif
+</pre></ul>
+
 <h2><a name="workqueues">4.4 Work Queues</a></h2>
 <p><b>Work Queues</b>.
   NuttX provides <i>work queues</i>.  Work queues are threads the service a queue of work items to be performed.  There are useful for off-loading work to a different threading context, for delayed processing, or for serializing activities.

Documentation/NuttxUserGuide.html

@@ -9731,37 +9731,6 @@ notify a task when a message is available on a queue.
     };
 </pre>
 
-<H3>3.4.9 Watchdog Data Types</H3>
-
-<p>
-  When a watchdog expires, the callback function with this
-  type is called:
-</p>
-<pre>
-    typedef void (*wdentry_t)(int argc, ...);
-</pre>
-<p>
-  Where argc is the number of uint32_t type arguments that follow.
-</p>
-<p>
-  The arguments are passed as <code>wdparm_t</code> values.  For systems where the <code>sizeof(pointer) &lt; sizeof(uint32_t)</code>, the following union defines the alignment of the pointer within the <code>uint32_t</code>.  For example, the SDCC MCS51 general pointer is 24-bits, but <code>uint32_t</code> is 32-bits (of course).
-</p>
-   We always have <code>sizeof(pointer) <= sizeof(uintptr_t)</code> by definitions.
-</p>
-<ul><pre>
-union wdparm_u
-{
-  FAR void     *pvarg; /* The size one generic point */
-  uint32_t      dwarg; /* Big enough for a 32-bit value in any case */
-  uintptr_t     uiarg; /* sizeof(uintptr_t) >= sizeof(pointer) */
-};
-
-#if UINTPTR_MAX >= UINT32_MAX
-typedef uintptr_t wdparm_t;
-#else
-typedef uint32_t  wdpartm_t;
-#endif
-</pre></ul>
 
 <table width ="100%">
   <tr bgcolor="#e4e4e4">

include/nuttx/wdog.h

@@ -106,7 +106,7 @@
  * alignment of the pointer within the uint32_t.  For example, the SDCC
  * MCS51 general pointer is 24-bits, but uint32_t is 32-bits (of course).
  *
- * We always have sizeof(pointer) <= sizeof(uintptr_t) by definitions.
+ * We always have sizeof(pointer) <= sizeof(uintptr_t) by definition.
  */
 
 union wdparm_u