diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 23520da45..261415e16 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -1483,6 +1483,9 @@
 
 5.19 2011-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
 
+	* arch/arm/stm32/stm32_idle.c -- During idle times, the STM32 now uses the
+	  WFI instruction to sleep in a reduced power mode until the next interrupt
+	  occurs (Contributed by Uros Platise).      
 	* NSH: 'mem' command renamed to 'free'.  Output is now more similar to the
 	  Linux 'free' command.
 	* NSH: Correct a redirection bug in NSH.  The following would not work; it
@@ -1500,7 +1503,13 @@
 	    nsh> cat test.txt
 	    This is a test
 
-	* drvers/pipes/pipe_common.c:  Driver open method eas not returning an EINTR
+	* drivers/pipes/pipe_common.c:  Driver open method eas not returning an EINTR
 	  error when it received a signal.  Instead, it just re-started the wait.  This
 	  makes it impossible to kill a background pipe operation from NSH.
-
+	* include/stdint.h -- Correct some errors in conditional compilation (submitted
+	  by Johannes Hampel).
+	* arch/arm/lpc17xx/lp17_idle.c -- Uses the same logic as the STM32: uses the
+	  WFI instruction to sleep in a reduced power mode until the next interrupt
+	  occurs.
+	* configs/olimex-lpc1766stk -- Added an LED encoded to indicate if the LPC1766
+	  is in sleeping.      
diff --git a/nuttx/Documentation/NuttX.html b/nuttx/Documentation/NuttX.html
index 44fc71a9e..56ddb6351 100644
--- a/nuttx/Documentation/NuttX.html
+++ b/nuttx/Documentation/NuttX.html
@@ -2085,6 +2085,9 @@ buildroot-1.9 2011-02-10 &lt;spudmonkey@racsa.co.cr&gt;
 <ul><pre>
 nuttx-5.19 2011-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 
+    * arch/arm/stm32/stm32_idle.c -- During idle times, the STM32 now uses the
+      WFI instruction to sleep in a reduced power mode until the next interrupt
+      occurs (Contributed by Uros Platise).      
     * NSH: 'mem' command renamed to 'free'.  Output is now more similar to the
       Linux 'free' command.
     * NSH: Correct a redirection bug in NSH.  The following would not work; it
@@ -2102,9 +2105,16 @@ nuttx-5.19 2011-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
         nsh> cat test.txt
         This is a test
 
-    * drvers/pipes/pipe_common.c:  Driver open method eas not returning an EINTR
+    * drivers/pipes/pipe_common.c --  Driver open method eas not returning an EINTR
       error when it received a signal.  Instead, it just re-started the wait.  This
       makes it impossible to kill a background pipe operation from NSH.
+    * include/stdint.h -- Correct some errors in conditional compilation (submitted
+      by Johannes Hampel).
+    * arch/arm/lpc17xx/lp17_idle.c -- Uses the same logic as the STM32: uses the
+      WFI instruction to sleep in a reduced power mode until the next interrupt
+      occurs.
+    * configs/olimex-lpc1766stk -- Added an LED encoded to indicate if the LPC1766
+      is in sleeping.      
 
 pascal-2.1 2011-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 
diff --git a/nuttx/TODO b/nuttx/TODO
index 9dcb56425..5fb772cd6 100644
--- a/nuttx/TODO
+++ b/nuttx/TODO
@@ -87,6 +87,10 @@ o Memory Managment (mm/)
   Description: Add an option to free all memory allocated by a task when the
                task exits. This is probably not be worth the overhead for a
                deeply embedded system.
+               There would be complexities with this implementation as well
+               because often one task allocates memory and then passes the
+               memory to another:  The task that "owns" the memory may not
+               be the same as the task that allocated the memory.
   Status:      Open
   Priority:    Medium/Low, a good feature to prevent memory leaks but would
                have negative impact on memory usage and code size.
diff --git a/nuttx/arch/arm/src/lpc17xx/Make.defs b/nuttx/arch/arm/src/lpc17xx/Make.defs
index 2b4ea0ffc..3665b9cce 100755
--- a/nuttx/arch/arm/src/lpc17xx/Make.defs
+++ b/nuttx/arch/arm/src/lpc17xx/Make.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/arm/src/lpc17xx/Make.defs
 #
-#   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2010-2011 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -41,7 +41,7 @@ HEAD_ASRC	= lpc17_vectors.S
 
 CMN_ASRCS	= up_saveusercontext.S up_fullcontextrestore.S up_switchcontext.S
 CMN_CSRCS	= up_assert.c up_blocktask.c up_copystate.c up_createstack.c \
-		  up_mdelay.c up_udelay.c up_exit.c up_idle.c up_initialize.c \
+		  up_mdelay.c up_udelay.c up_exit.c up_initialize.c \
 		  up_initialstate.c up_interruptcontext.c up_modifyreg8.c \
 		  up_modifyreg16.c up_modifyreg32.c up_releasepending.c \
 		  up_releasestack.c up_reprioritizertr.c up_schedulesigaction.c \
@@ -52,8 +52,8 @@ CMN_CSRCS	= up_assert.c up_blocktask.c up_copystate.c up_createstack.c \
 
 CHIP_ASRCS	=
 CHIP_CSRCS	= lpc17_allocateheap.c lpc17_clockconfig.c lpc17_clrpend.c \
-		  lpc17_gpio.c lpc17_irq.c lpc17_lowputc.c lpc17_serial.c \
-		  lpc17_spi.c lpc17_ssp.c lpc17_start.c lpc17_timerisr.c
+		  lpc17_gpio.c lpc17_idle.c lpc17_irq.c lpc17_lowputc.c \
+		  lpc17_serial.c lpc17_spi.c lpc17_ssp.c lpc17_start.c lpc17_timerisr.c
 
 # Configuration-dependent LPC17xx files
 
diff --git a/nuttx/arch/arm/src/lpc17xx/lpc17_idle.c b/nuttx/arch/arm/src/lpc17xx/lpc17_idle.c
new file mode 100755
index 000000000..6e55bca9e
--- /dev/null
+++ b/nuttx/arch/arm/src/lpc17xx/lpc17_idle.c
@@ -0,0 +1,104 @@
+/****************************************************************************
+ *  arch/arm/src/lpc17/lpc17_idle.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <arch/board/board.h>
+#include <nuttx/config.h>
+
+#include <nuttx/arch.h>
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Does the board support an IDLE LED to indicate that the board is in the
+ * IDLE state?
+ */
+
+#if defined(CONFIG_ARCH_LEDS) && defined(LED_IDLE)
+#  define BEGIN_IDLE() up_ledon(LED_IDLE)
+#  define END_IDLE()   up_ledoff(LED_IDLE)
+#else
+#  define BEGIN_IDLE()
+#  define END_IDLE()
+#endif
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_idle
+ *
+ * Description:
+ *   up_idle() is the logic that will be executed when their is no other
+ *   ready-to-run task.  This is processor idle time and will continue until
+ *   some interrupt occurs to cause a context switch from the idle task.
+ *
+ *   Processing in this state may be processor-specific. e.g., this is where
+ *   power management operations might be performed.
+ *
+ ****************************************************************************/
+
+void up_idle(void)
+{
+#if defined(CONFIG_SUPPRESS_INTERRUPTS) || defined(CONFIG_SUPPRESS_TIMER_INTS)
+  /* If the system is idle and there are no timer interrupts, then process
+   * "fake" timer interrupts. Hopefully, something will wake up.
+   */
+
+  sched_process_timer();
+#else
+
+  /* Sleep until an interrupt occurs to save power */
+
+  BEGIN_IDLE();
+  asm("WFI");
+  END_IDLE();
+#endif
+}
+
diff --git a/nuttx/configs/nucleus2g/README.txt b/nuttx/configs/nucleus2g/README.txt
index 559c16ef3..d57980b0c 100755
--- a/nuttx/configs/nucleus2g/README.txt
+++ b/nuttx/configs/nucleus2g/README.txt
@@ -250,6 +250,7 @@ LEDs
     #define LED_SIGNAL                 5  /*  NC     NC    ON  (momentary) */
     #define LED_ASSERTION              6  /*  NC     NC    ON  (momentary) */
     #define LED_PANIC                  7  /*  NC     NC    ON  (0.5Hz flashing) */
+    #undef  LED_IDLE                      /* Sleep mode indication not supported */
 
   After the system is booted, this logic will no longer use LEDs 1 and 2.  They
   are then available for use the application software using lpc17_led1() and
diff --git a/nuttx/configs/olimex-lpc1766stk/README.txt b/nuttx/configs/olimex-lpc1766stk/README.txt
index d09d504d0..98b0bb135 100755
--- a/nuttx/configs/olimex-lpc1766stk/README.txt
+++ b/nuttx/configs/olimex-lpc1766stk/README.txt
@@ -329,6 +329,9 @@ LEDs
     if you see this at all, it probably means that the system is hanging up
     somewhere in the initialization phases.
   - ON means that the OS completed initialization.
+  - Glowing means that the LPC17 is running in a reduced power mode: LED1 is
+    turned off when the processor enters sleep mode and back on when it wakesup
+    up.
 
   LED2:
   - ON/OFF toggles means that various events are happening.
@@ -341,25 +344,32 @@ LEDs
   NOTE:  LED2 is controlled by a jumper labeled: ACC_IRQ/LED2.  That jump must be
   in the LED2 position in order to support LED2.
 
-  LED1  LED2      Meaning
-  ----- --------  --------------------------------------------------------------------
-   OFF   OFF      Still initializing and there is no interrupt activity. 
-                  Initialization is very fast so if you see this, it probably means
-                  that the system is hung up somewhere in the initialization phases.
-   OFF   Glowing  Still initializing (see above) but taking interrupts.
-   OFF   ON       This would mean that (1) initialization did not complete but the
-                  software is hung, perhaps in an infinite loop, somewhere inside
-                  of an interrupt handler.
-   OFF   Flashing Ooops!  We crashed before finishing initialization.
+  LED1    LED2      Meaning
+  ------- --------  --------------------------------------------------------------------
+   OFF    OFF      Still initializing and there is no interrupt activity. 
+                    Initialization is very fast so if you see this, it probably means
+                    that the system is hung up somewhere in the initialization phases.
+   OFF     Glowing  Still initializing (see above) but taking interrupts.
+   OFF     ON       This would mean that (1) initialization did not complete but the
+                    software is hung, perhaps in an infinite loop, somewhere inside
+                    of an interrupt handler.
+   OFF     Flashing Ooops!  We crashed before finishing initialization (or, perhaps
+                    after initialization, during an interrupt while the LPC17xx was
+                    sleeping -- see below).
  
-   ON    OFF      The system has completed initialization, but is apparently not taking
-                  any interrupts.
-   ON    Glowing  This is the normal healthy state: The OS successfully initialized
-                  and is taking interrupts.
-   ON    ON       This would mean that (1) the OS complete initialization, but (2)
-                  the software is hung, perhaps in an infinite loop, somewhere inside
-                  of a signal or interrupt handler.
-   ON    Flashing Ooops!  We crashed sometime after initialization.
+   ON      OFF      The system has completed initialization, but is apparently not taking
+                    any interrupts.
+   ON      Glowing  The OS successfully initialized and is taking interrupts (but, for
+                    some reason, is never entering a reduced power mode -- perhaps the
+                    CPU is very busy?).
+   ON      ON       This would mean that (1) the OS complete initialization, but (2)
+                    the software is hung, perhaps in an infinite loop, somewhere inside
+                    of a signal or interrupt handler.
+   Glowing Glowing  This is also a normal healthy state: The OS successfully initialized,
+                    is running in reduced power mode, but taking interrupts.  The glow
+                    is very faint and you may have to dim the lights to see that LEDs are
+                    active at all!
+   ON      Flashing Ooops!  We crashed sometime after initialization.
 
 Using OpenOCD and GDB with an FT2232 JTAG emulator
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/nuttx/configs/olimex-lpc1766stk/include/board.h b/nuttx/configs/olimex-lpc1766stk/include/board.h
index 275714da0..33c44b885 100755
--- a/nuttx/configs/olimex-lpc1766stk/include/board.h
+++ b/nuttx/configs/olimex-lpc1766stk/include/board.h
@@ -136,11 +136,12 @@
 #define LED_HEAPALLOCATE           0  /*  OFF  OFF = Still initializing */
 #define LED_IRQSENABLED            0  /*  OFF  OFF = Still initializing */
 #define LED_STACKCREATED           1  /*  ON   OFF = Initialization complete */
-#define LED_INIRQ                  2  /*  NC   ON  = In an interrupt handler */
-#define LED_SIGNAL                 2  /*  NC   ON  = In a signal handler */
-#define LED_ASSERTION              2  /*  NC   ON  = In an assertion */
-#define LED_PANIC                  2  /*  NC   ON  = Oops! We crashed. (flashing) */
-
+#define LED_INIRQ                  2  /*  N/C  ON  = In an interrupt handler */
+#define LED_SIGNAL                 2  /*  N/C  ON  = In a signal handler (glowing) */
+#define LED_ASSERTION              2  /*  N/C  ON  = In an assertion */
+#define LED_PANIC                  2  /*  N/C  ON  = Oops! We crashed. (flashing) */
+#define LED_IDLE                   3  /*  OFF  N/C = LPC17 in sleep mode (LED1 glowing) */
+ 
 /* Alternate pin selections *********************************************************/
 
 /* CAN1 GPIO                        PIN  SIGNAL NAME
diff --git a/nuttx/configs/olimex-lpc1766stk/src/up_leds.c b/nuttx/configs/olimex-lpc1766stk/src/up_leds.c
index 73ae0c3eb..da23e18d3 100755
--- a/nuttx/configs/olimex-lpc1766stk/src/up_leds.c
+++ b/nuttx/configs/olimex-lpc1766stk/src/up_leds.c
@@ -2,7 +2,7 @@
  * configs/olimex-lpc1766stk/src/up_leds.c
  * arch/arm/src/board/up_leds.c
  *
- *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2010-2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -92,6 +92,8 @@
  * Private Data
  ****************************************************************************/
 
+static bool g_uninitialized = true;
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -132,11 +134,16 @@ void up_ledon(int led)
        case 1 : /* STACKCREATED */
         lpc17_gpiowrite(LPC1766STK_LED1, false);
         lpc17_gpiowrite(LPC1766STK_LED2, true);
+        g_uninitialized = false;
         break;
 
        case 2 : /* INIRQ, SIGNAL, ASSERTION, PANIC */
         lpc17_gpiowrite(LPC1766STK_LED2, false);
         break;
+
+       case 3 : /* IDLE */
+        lpc17_gpiowrite(LPC1766STK_LED1, true);
+        break;
     }
 }
 
@@ -152,9 +159,14 @@ void up_ledoff(int led)
        case 0 : /* STARTED, HEAPALLOCATE, IRQSENABLED */
        case 1 : /* STACKCREATED */
         lpc17_gpiowrite(LPC1766STK_LED1, true);
+
        case 2 : /* INIRQ, SIGNAL, ASSERTION, PANIC */
         lpc17_gpiowrite(LPC1766STK_LED2, true);
         break;
+
+       case 3 : /* IDLE */
+        lpc17_gpiowrite(LPC1766STK_LED1, g_uninitialized);
+        break;
     }
 }
 #endif /* CONFIG_ARCH_LEDS */
diff --git a/nuttx/configs/stm3210e-eval/README.txt b/nuttx/configs/stm3210e-eval/README.txt
index 9d0807087..2a58577f6 100755
--- a/nuttx/configs/stm3210e-eval/README.txt
+++ b/nuttx/configs/stm3210e-eval/README.txt
@@ -228,6 +228,7 @@ They are encoded as follows:
 	LED_SIGNAL			In a signal handler***  N/C		ON		N/C		OFF
 	LED_ASSERTION		An assertion failed		ON		ON		N/C		OFF
 	LED_PANIC			The system has crashed	N/C		N/C		N/C		ON
+    LED_IDLE            STM32 is is sleep mode  (Optional, not used)
 
   * If LED1, LED2, LED3 are statically on, then NuttX probably failed to boot
     and these LEDs will give you some indication of where the failure was
diff --git a/nuttx/include/stdint.h b/nuttx/include/stdint.h
index 3bd1d9f47..d44b13639 100755
--- a/nuttx/include/stdint.h
+++ b/nuttx/include/stdint.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * include/stdint.h
  *
- *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009, 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -60,7 +60,7 @@
 #define INT16_MAX           0x7fff
 #define UINT16_MAX          0xffff
 
-#ifdef __INT64_DEFINED
+#ifdef __INT24_DEFINED
 #  define INT24_MIN         0x800000
 #  define INT24_MAX         0x7fffff
 #  define UINT24_MAX        0xffffff
@@ -86,7 +86,7 @@
 #define INT16_LEASTN_MAX    0x7fff
 #define UINT16_LEASTN_MAX   0xffff
 
-#ifdef __INT64_DEFINED
+#ifdef __INT24_DEFINED
 #  define INT24_LEASTN_MIN  0x800000
 #  define INT24_LEASTN_MAX  0x7fffff
 #  define UINT24_LEASTN_MAX 0xffffff
@@ -112,7 +112,7 @@
 #define INT16_FASTN_MAX     0x7fff
 #define UINT16_FASTN_MAX    0xffff
 
-#ifdef __INT64_DEFINED
+#ifdef __INT24_DEFINED
 #  define INT24_FASTN_MIN   0x800000
 #  define INT24_FASTN_MAX   0x7fffff
 #  define UINT24_FASTN_MAX  0xffffff