From 3ea77b1644668000ea12bae4837c920bfd4dce5c Mon Sep 17 00:00:00 2001
From: richardbarry <richardbarry@1d2547de-c912-0410-9cb9-b8ca96c0e9e2>
Date: Mon, 29 Oct 2012 15:56:26 +0000
Subject: [PATCH] Make CM3/4 tick configuration a weak function to allow
 application writers to use an alternative tick source.

git-svn-id: https://svn.code.sf.net/p/freertos/code/trunk@1803 1d2547de-c912-0410-9cb9-b8ca96c0e9e2
---
 FreeRTOS/Source/include/FreeRTOS.h            |   4 +-
 FreeRTOS/Source/portable/GCC/ARM_CM3/port.c   |  56 +++++---
 FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c  |  54 +++++---
 .../Source/portable/GCC/ARM_CM4F/portmacro.h  |   2 -
 FreeRTOS/Source/portable/IAR/ARM_CM3/port.c   |  75 ++++++-----
 FreeRTOS/Source/portable/IAR/ARM_CM4F/port.c  |  75 ++++++-----
 FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c  |  82 ++++++++----
 FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c |  84 +++++++-----
 FreeRTOS/Source/tasks.c                       | 120 ++++++++++--------
 9 files changed, 338 insertions(+), 214 deletions(-)

diff --git a/FreeRTOS/Source/include/FreeRTOS.h b/FreeRTOS/Source/include/FreeRTOS.h
index c9eda0fd7..2c0c28d8c 100644
--- a/FreeRTOS/Source/include/FreeRTOS.h
+++ b/FreeRTOS/Source/include/FreeRTOS.h
@@ -535,11 +535,11 @@ typedef portBASE_TYPE (*pdTASK_HOOK_CODE)( void * );
 #endif
 
 #ifndef configPRE_SLEEP_PROCESSING
-	#define configPRE_SLEEP_PROCESSING()
+	#define configPRE_SLEEP_PROCESSING( x )
 #endif
 
 #ifndef configPOST_SLEEP_PROCESSING
-	#define configPOST_SLEEP_PROCESSING()
+	#define configPOST_SLEEP_PROCESSING( x )
 #endif
 
 #endif /* INC_FREERTOS_H */
diff --git a/FreeRTOS/Source/portable/GCC/ARM_CM3/port.c b/FreeRTOS/Source/portable/GCC/ARM_CM3/port.c
index 440109489..206f484f5 100644
--- a/FreeRTOS/Source/portable/GCC/ARM_CM3/port.c
+++ b/FreeRTOS/Source/portable/GCC/ARM_CM3/port.c
@@ -83,15 +83,7 @@ FreeRTOS.org versions prior to V4.4.0 did not include this definition. */
 
 #ifndef configSYSTICK_CLOCK_HZ
 	#define configSYSTICK_CLOCK_HZ configCPU_CLOCK_HZ
-	#if configUSE_TICKLESS_IDLE == 1
-		static const unsigned long ulStoppedTimerCompensation = 45UL;
-	#endif
-#else /* configSYSTICK_CLOCK_HZ */
-	#if configUSE_TICKLESS_IDLE == 1
-		/* Assumes the SysTick clock is slower than the CPU clock. */
-		static const unsigned long ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
-	#endif
-#endif	/* configSYSTICK_CLOCK_HZ */
+#endif
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG			( * ( ( volatile unsigned long * ) 0xe000e010 ) )
@@ -123,9 +115,11 @@ variable. */
 static unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa;
 
 /*
- * Setup the timer to generate the tick interrupts.
+ * Setup the timer to generate the tick interrupts.  The implementation in this
+ * file is weak to allow application writers to change the timer used to 
+ * generate the tick interrupt.
  */
-static void prvSetupTimerInterrupt( void );
+void vPortSetupTimerInterrupt( void );
 
 /*
  * Exception handlers.
@@ -144,7 +138,9 @@ static void prvPortStartFirstTask( void ) __attribute__ (( naked ));
 /*
  * The number of SysTick increments that make up one tick period.
  */
-static unsigned long ulTimerReloadValueForOneTick = 0;
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulTimerReloadValueForOneTick = 0;
+#endif
 
 /*
  * The maximum number of tick periods that can be suppressed is limited by the
@@ -154,6 +150,13 @@ static unsigned long ulTimerReloadValueForOneTick = 0;
 	static unsigned long xMaximumPossibleSuppressedTicks = 0;
 #endif /* configUSE_TICKLESS_IDLE */
 
+/*
+ * Compensate for the CPU cycles that pass while the SysTick is stopped (low
+ * power functionality only.
+ */
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulStoppedTimerCompensation = 0;
+#endif /* configUSE_TICKLESS_IDLE */
 
 /*-----------------------------------------------------------*/
 
@@ -226,7 +229,7 @@ portBASE_TYPE xPortStartScheduler( void )
 
 	/* Start the timer that generates the tick ISR.  Interrupts are disabled
 	here already. */
-	prvSetupTimerInterrupt();
+	vPortSetupTimerInterrupt();
 
 	/* Initialise the critical nesting count ready for the first task. */
 	uxCriticalNesting = 0;
@@ -295,6 +298,9 @@ __attribute__(( naked )) void vPortClearInterruptMask( unsigned long ulNewMaskVa
 		"	bx lr												\n" \
 		:::"r0"														\
 	);
+	
+	/* Just to avoid compiler warnings. */
+	( void ) ulNewMaskValue;
 }
 /*-----------------------------------------------------------*/
 
@@ -340,6 +346,10 @@ void xPortSysTickHandler( void )
 		portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
 	#endif
 
+	/* Only reset the systick load register if configUSE_TICKLESS_IDLE is set to
+	1.  If it is set to 0 tickless idle is not being used.  If it is set to a 
+	value other than 0 or 1 then a timer other than the SysTick is being used
+	to generate the tick interrupt. */
 	#if configUSE_TICKLESS_IDLE == 1
 		portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
 	#endif
@@ -403,9 +413,12 @@ void xPortSysTickHandler( void )
 			portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 
 			/* Sleep until something happens. */
-			configPRE_SLEEP_PROCESSING();
-			__asm volatile( "wfi" );
-			configPOST_SLEEP_PROCESSING();
+			configPRE_SLEEP_PROCESSING( xExpectedIdleTime );
+			if( xExpectedIdleTime > 0 )
+			{
+				__asm volatile( "wfi" );
+			}
+			configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
 
 			/* Stop SysTick.  Again, the time the SysTick is stopped for is
 			accounted for as best it can be, but using the tickless mode will
@@ -460,16 +473,19 @@ void xPortSysTickHandler( void )
  * Setup the systick timer to generate the tick interrupts at the required
  * frequency.
  */
-void prvSetupTimerInterrupt( void )
+__attribute__(( weak )) void vPortSetupTimerInterrupt( void )
 {
-	/* Calculate the constants required to configure the tick interrupt. */
-	ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
+	/* Calculate the constants required to configure the tick interrupt. */		
 	#if configUSE_TICKLESS_IDLE == 1
+	{
+		ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
 		xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
+		ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
+	}
 	#endif /* configUSE_TICKLESS_IDLE */
 
 	/* Configure SysTick to interrupt at the requested rate. */
-	portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
+	portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;;
 	portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 }
 /*-----------------------------------------------------------*/
diff --git a/FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c b/FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c
index 41da9a79e..b9394cc55 100644
--- a/FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c
+++ b/FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c
@@ -80,15 +80,7 @@
 
 #ifndef configSYSTICK_CLOCK_HZ
 	#define configSYSTICK_CLOCK_HZ configCPU_CLOCK_HZ
-	#if configUSE_TICKLESS_IDLE == 1
-		static const unsigned long ulStoppedTimerCompensation = 45UL;
-	#endif
-#else /* configSYSTICK_CLOCK_HZ */
-	#if configUSE_TICKLESS_IDLE == 1
-		/* Assumes the SysTick clock is slower than the CPU clock. */
-		static const unsigned long ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
-	#endif
-#endif	/* configSYSTICK_CLOCK_HZ */
+#endif
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG			( * ( ( volatile unsigned long * ) 0xe000e010 ) )
@@ -125,9 +117,11 @@ variable. */
 static unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa;
 
 /*
- * Setup the timer to generate the tick interrupts.
+ * Setup the timer to generate the tick interrupts.  The implementation in this
+ * file is weak to allow application writers to change the timer used to 
+ * generate the tick interrupt.
  */
-static void prvSetupTimerInterrupt( void );
+void vPortSetupTimerInterrupt( void );
 
 /*
  * Exception handlers.
@@ -151,7 +145,9 @@ static void prvPortStartFirstTask( void ) __attribute__ (( naked ));
 /*
  * The number of SysTick increments that make up one tick period.
  */
-static unsigned long ulTimerReloadValueForOneTick = 0;
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulTimerReloadValueForOneTick = 0;
+#endif
 
 /*
  * The maximum number of tick periods that can be suppressed is limited by the
@@ -161,6 +157,13 @@ static unsigned long ulTimerReloadValueForOneTick = 0;
 	static unsigned long xMaximumPossibleSuppressedTicks = 0;
 #endif /* configUSE_TICKLESS_IDLE */
 
+/*
+ * Compensate for the CPU cycles that pass while the SysTick is stopped (low
+ * power functionality only.
+ */
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulStoppedTimerCompensation = 0;
+#endif /* configUSE_TICKLESS_IDLE */
 
 /*-----------------------------------------------------------*/
 
@@ -244,7 +247,7 @@ portBASE_TYPE xPortStartScheduler( void )
 
 	/* Start the timer that generates the tick ISR.  Interrupts are disabled
 	here already. */
-	prvSetupTimerInterrupt();
+	vPortSetupTimerInterrupt();
 
 	/* Initialise the critical nesting count ready for the first task. */
 	uxCriticalNesting = 0;
@@ -375,6 +378,10 @@ void xPortSysTickHandler( void )
 		portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
 	#endif
 
+	/* Only reset the systick load register if configUSE_TICKLESS_IDLE is set to
+	1.  If it is set to 0 tickless idle is not being used.  If it is set to a 
+	value other than 0 or 1 then a timer other than the SysTick is being used
+	to generate the tick interrupt. */
 	#if configUSE_TICKLESS_IDLE == 1
 		portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
 	#endif
@@ -438,9 +445,12 @@ void xPortSysTickHandler( void )
 			portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 
 			/* Sleep until something happens. */
-			configPRE_SLEEP_PROCESSING();
-			__asm volatile( "wfi" );
-			configPOST_SLEEP_PROCESSING();
+			configPRE_SLEEP_PROCESSING( xExpectedIdleTime );
+			if( xExpectedIdleTime > 0 )
+			{
+				__asm volatile( "wfi" );
+			}
+			configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
 
 			/* Stop SysTick.  Again, the time the SysTick is stopped for is
 			accounted for as best it can be, but using the tickless mode will
@@ -495,17 +505,19 @@ void xPortSysTickHandler( void )
  * Setup the systick timer to generate the tick interrupts at the required
  * frequency.
  */
-void prvSetupTimerInterrupt( void )
+__attribute__(( weak )) void vPortSetupTimerInterrupt( void )
 {
-	/* Calculate the constants required to configure the tick interrupt. */
-	ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
+	/* Calculate the constants required to configure the tick interrupt. */		
 	#if configUSE_TICKLESS_IDLE == 1
+	{
+		ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
 		xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
+		ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
+	}
 	#endif /* configUSE_TICKLESS_IDLE */
 
-
 	/* Configure SysTick to interrupt at the requested rate. */
-	portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
+	portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;;
 	portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 }
 /*-----------------------------------------------------------*/
diff --git a/FreeRTOS/Source/portable/GCC/ARM_CM4F/portmacro.h b/FreeRTOS/Source/portable/GCC/ARM_CM4F/portmacro.h
index d74c9bb2c..5bdcc58f0 100644
--- a/FreeRTOS/Source/portable/GCC/ARM_CM4F/portmacro.h
+++ b/FreeRTOS/Source/portable/GCC/ARM_CM4F/portmacro.h
@@ -111,9 +111,7 @@ extern "C" {
 
 /* Scheduler utilities. */
 extern void vPortYieldFromISR( void );
-
 #define portYIELD()					vPortYieldFromISR()
-
 #define portEND_SWITCHING_ISR( xSwitchRequired ) if( xSwitchRequired ) vPortYieldFromISR()
 /*-----------------------------------------------------------*/
 
diff --git a/FreeRTOS/Source/portable/IAR/ARM_CM3/port.c b/FreeRTOS/Source/portable/IAR/ARM_CM3/port.c
index 2601d5035..c501e7259 100644
--- a/FreeRTOS/Source/portable/IAR/ARM_CM3/port.c
+++ b/FreeRTOS/Source/portable/IAR/ARM_CM3/port.c
@@ -1,7 +1,7 @@
 /*
     FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.
 
-    FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT 
+    FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT
     http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
 
     ***************************************************************************
@@ -42,7 +42,7 @@
     FreeRTOS WEB site.
 
     1 tab == 4 spaces!
-    
+
     ***************************************************************************
      *                                                                       *
      *    Having a problem?  Start by reading the FAQ "My application does   *
@@ -52,17 +52,17 @@
      *                                                                       *
     ***************************************************************************
 
-    
-    http://www.FreeRTOS.org - Documentation, training, latest versions, license 
-    and contact details.  
-    
+
+    http://www.FreeRTOS.org - Documentation, training, latest versions, license
+    and contact details.
+
     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
     including FreeRTOS+Trace - an indispensable productivity tool.
 
-    Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell 
-    the code with commercial support, indemnification, and middleware, under 
+    Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
+    the code with commercial support, indemnification, and middleware, under
     the OpenRTOS brand: http://www.OpenRTOS.com.  High Integrity Systems also
-    provide a safety engineered and independently SIL3 certified version under 
+    provide a safety engineered and independently SIL3 certified version under
     the SafeRTOS brand: http://www.SafeRTOS.com.
 */
 
@@ -70,6 +70,9 @@
  * Implementation of functions defined in portable.h for the ARM CM3 port.
  *----------------------------------------------------------*/
 
+/* IAR includes. */
+#include <intrinsics.h>
+
 /* Scheduler includes. */
 #include "FreeRTOS.h"
 #include "task.h"
@@ -80,15 +83,7 @@
 
 #ifndef configSYSTICK_CLOCK_HZ
 	#define configSYSTICK_CLOCK_HZ configCPU_CLOCK_HZ
-	#if configUSE_TICKLESS_IDLE == 1
-		static const unsigned long ulStoppedTimerCompensation = 45UL;
-	#endif
-#else /* configSYSTICK_CLOCK_HZ */
-	#if configUSE_TICKLESS_IDLE == 1
-		/* Assumes the SysTick clock is slower than the CPU clock. */
-		static const unsigned long ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
-	#endif
-#endif	/* configSYSTICK_CLOCK_HZ */
+#endif
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG			( * ( ( volatile unsigned long * ) 0xe000e010 ) )
@@ -123,9 +118,11 @@ variable. */
 static unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa;
 
 /*
- * Setup the timer to generate the tick interrupts.
+ * Setup the timer to generate the tick interrupts.  The implementation in this
+ * file is weak to allow application writers to change the timer used to
+ * generate the tick interrupt.
  */
-static void prvSetupTimerInterrupt( void );
+void vPortSetupTimerInterrupt( void );
 
 /*
  * Exception handlers.
@@ -142,7 +139,9 @@ extern void vPortStartFirstTask( void );
 /*
  * The number of SysTick increments that make up one tick period.
  */
-static unsigned long ulTimerReloadValueForOneTick = 0;
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulTimerReloadValueForOneTick = 0;
+#endif
 
 /*
  * The maximum number of tick periods that can be suppressed is limited by the
@@ -152,6 +151,14 @@ static unsigned long ulTimerReloadValueForOneTick = 0;
 	static unsigned long xMaximumPossibleSuppressedTicks = 0;
 #endif /* configUSE_TICKLESS_IDLE */
 
+/*
+ * Compensate for the CPU cycles that pass while the SysTick is stopped (low
+ * power functionality only.
+ */
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulStoppedTimerCompensation = 0;
+#endif /* configUSE_TICKLESS_IDLE */
+
 /*-----------------------------------------------------------*/
 
 /*
@@ -186,7 +193,7 @@ portBASE_TYPE xPortStartScheduler( void )
 
 	/* Start the timer that generates the tick ISR.  Interrupts are disabled
 	here already. */
-	prvSetupTimerInterrupt();
+	vPortSetupTimerInterrupt();
 
 	/* Initialise the critical nesting count ready for the first task. */
 	uxCriticalNesting = 0;
@@ -237,6 +244,10 @@ void xPortSysTickHandler( void )
 		portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
 	#endif
 
+	/* Only reset the systick load register if configUSE_TICKLESS_IDLE is set to
+	1.  If it is set to 0 tickless idle is not being used.  If it is set to a
+	value other than 0 or 1 then a timer other than the SysTick is being used
+	to generate the tick interrupt. */
 	#if configUSE_TICKLESS_IDLE == 1
 		portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
 	#endif
@@ -300,9 +311,12 @@ void xPortSysTickHandler( void )
 			portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 
 			/* Sleep until something happens. */
-			configPRE_SLEEP_PROCESSING();
-			__WFI();
-			configPOST_SLEEP_PROCESSING();
+			configPRE_SLEEP_PROCESSING( xExpectedIdleTime );
+			if( xExpectedIdleTime > 0 )
+			{
+				__WFI();
+			}
+			configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
 
 			/* Stop SysTick.  Again, the time the SysTick is stopped for is
 			accounted for as best it can be, but using the tickless mode will
@@ -357,16 +371,19 @@ void xPortSysTickHandler( void )
  * Setup the systick timer to generate the tick interrupts at the required
  * frequency.
  */
-void prvSetupTimerInterrupt( void )
+__weak void vPortSetupTimerInterrupt( void )
 {
-	/* Configure the constants required to setup the tick interrupt. */
-	ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
+	/* Calculate the constants required to configure the tick interrupt. */		
 	#if configUSE_TICKLESS_IDLE == 1
+	{
+		ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
 		xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
+		ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
+	}
 	#endif /* configUSE_TICKLESS_IDLE */
 
 	/* Configure SysTick to interrupt at the requested rate. */
-	portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
+	portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;;
 	portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 }
 /*-----------------------------------------------------------*/
diff --git a/FreeRTOS/Source/portable/IAR/ARM_CM4F/port.c b/FreeRTOS/Source/portable/IAR/ARM_CM4F/port.c
index 3ee8eb349..f6434caef 100644
--- a/FreeRTOS/Source/portable/IAR/ARM_CM4F/port.c
+++ b/FreeRTOS/Source/portable/IAR/ARM_CM4F/port.c
@@ -1,7 +1,7 @@
 /*
     FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.
 
-    FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT 
+    FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT
     http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
 
     ***************************************************************************
@@ -42,7 +42,7 @@
     FreeRTOS WEB site.
 
     1 tab == 4 spaces!
-    
+
     ***************************************************************************
      *                                                                       *
      *    Having a problem?  Start by reading the FAQ "My application does   *
@@ -52,17 +52,17 @@
      *                                                                       *
     ***************************************************************************
 
-    
-    http://www.FreeRTOS.org - Documentation, training, latest versions, license 
-    and contact details.  
-    
+
+    http://www.FreeRTOS.org - Documentation, training, latest versions, license
+    and contact details.
+
     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
     including FreeRTOS+Trace - an indispensable productivity tool.
 
-    Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell 
-    the code with commercial support, indemnification, and middleware, under 
+    Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
+    the code with commercial support, indemnification, and middleware, under
     the OpenRTOS brand: http://www.OpenRTOS.com.  High Integrity Systems also
-    provide a safety engineered and independently SIL3 certified version under 
+    provide a safety engineered and independently SIL3 certified version under
     the SafeRTOS brand: http://www.SafeRTOS.com.
 */
 
@@ -70,6 +70,9 @@
  * Implementation of functions defined in portable.h for the ARM CM4F port.
  *----------------------------------------------------------*/
 
+/* Compiler includes. */
+#include <intrinsics.h>
+
 /* Scheduler includes. */
 #include "FreeRTOS.h"
 #include "task.h"
@@ -84,15 +87,7 @@
 
 #ifndef configSYSTICK_CLOCK_HZ
 	#define configSYSTICK_CLOCK_HZ configCPU_CLOCK_HZ
-	#if configUSE_TICKLESS_IDLE == 1
-		static const unsigned long ulStoppedTimerCompensation = 45UL;
-	#endif
-#else /* configSYSTICK_CLOCK_HZ */
-	#if configUSE_TICKLESS_IDLE == 1
-		/* Assumes the SysTick clock is slower than the CPU clock. */
-		static const unsigned long ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
-	#endif
-#endif	/* configSYSTICK_CLOCK_HZ */
+#endif
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG			( * ( ( volatile unsigned long * ) 0xe000e010 ) )
@@ -125,9 +120,11 @@ variable. */
 static unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa;
 
 /*
- * Setup the timer to generate the tick interrupts.
+ * Setup the timer to generate the tick interrupts.  The implementation in this
+ * file is weak to allow application writers to change the timer used to
+ * generate the tick interrupt.
  */
-static void prvSetupTimerInterrupt( void );
+void vPortSetupTimerInterrupt( void );
 
 /*
  * Exception handlers.
@@ -149,7 +146,9 @@ extern void vPortEnableVFP( void );
 /*
  * The number of SysTick increments that make up one tick period.
  */
-static unsigned long ulTimerReloadValueForOneTick = 0;
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulTimerReloadValueForOneTick = 0;
+#endif
 
 /*
  * The maximum number of tick periods that can be suppressed is limited by the
@@ -159,6 +158,14 @@ static unsigned long ulTimerReloadValueForOneTick = 0;
 	static unsigned long xMaximumPossibleSuppressedTicks = 0;
 #endif /* configUSE_TICKLESS_IDLE */
 
+/*
+ * Compensate for the CPU cycles that pass while the SysTick is stopped (low
+ * power functionality only.
+ */
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulStoppedTimerCompensation = 0;
+#endif /* configUSE_TICKLESS_IDLE */
+
 /*-----------------------------------------------------------*/
 
 /*
@@ -205,7 +212,7 @@ portBASE_TYPE xPortStartScheduler( void )
 
 	/* Start the timer that generates the tick ISR.  Interrupts are disabled
 	here already. */
-	prvSetupTimerInterrupt();
+	vPortSetupTimerInterrupt();
 
 	/* Initialise the critical nesting count ready for the first task. */
 	uxCriticalNesting = 0;
@@ -262,6 +269,10 @@ void xPortSysTickHandler( void )
 		portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
 	#endif
 
+	/* Only reset the systick load register if configUSE_TICKLESS_IDLE is set to
+	1.  If it is set to 0 tickless idle is not being used.  If it is set to a
+	value other than 0 or 1 then a timer other than the SysTick is being used
+	to generate the tick interrupt. */
 	#if configUSE_TICKLESS_IDLE == 1
 		portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
 	#endif
@@ -325,9 +336,12 @@ void xPortSysTickHandler( void )
 			portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 
 			/* Sleep until something happens. */
-			configPRE_SLEEP_PROCESSING();
-			__WFI();
-			configPOST_SLEEP_PROCESSING();
+			configPRE_SLEEP_PROCESSING( xExpectedIdleTime );
+			if( xExpectedIdleTime > 0 )
+			{
+				__WFI();
+			}
+			configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
 
 			/* Stop SysTick.  Again, the time the SysTick is stopped for is
 			accounted for as best it can be, but using the tickless mode will
@@ -382,16 +396,19 @@ void xPortSysTickHandler( void )
  * Setup the systick timer to generate the tick interrupts at the required
  * frequency.
  */
-void prvSetupTimerInterrupt( void )
+__weak void vPortSetupTimerInterrupt( void )
 {
-	/* Configure the constants required to setup the tick interrupt. */
-	ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
+	/* Calculate the constants required to configure the tick interrupt. */		
 	#if configUSE_TICKLESS_IDLE == 1
+	{
+		ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
 		xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
+		ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
+	}
 	#endif /* configUSE_TICKLESS_IDLE */
 
 	/* Configure SysTick to interrupt at the requested rate. */
-	portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
+	portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;;
 	portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 }
 /*-----------------------------------------------------------*/
diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c
index 5c3a5534e..be3d8e643 100644
--- a/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c
+++ b/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c
@@ -84,15 +84,16 @@
 
 #ifndef configSYSTICK_CLOCK_HZ
 	#define configSYSTICK_CLOCK_HZ configCPU_CLOCK_HZ
-	#if configUSE_TICKLESS_IDLE == 1
-		static const unsigned long ulStoppedTimerCompensation = 45UL;
-	#endif
-#else /* configSYSTICK_CLOCK_HZ */
-	#if configUSE_TICKLESS_IDLE == 1
-		/* Assumes the SysTick clock is slower than the CPU clock. */
-		static const unsigned long ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
-	#endif
-#endif	/* configSYSTICK_CLOCK_HZ */
+#endif
+
+/* The __weak attribute does not work as you might expect with the Keil tools
+so the configOVERRIDE_DEFAULT_TICK_CONFIGURATION constant must be set to 1 if
+the application writer wants to provide their own implementation of 
+vPortSetupTimerInterrupt().  Ensure configOVERRIDE_DEFAULT_TICK_CONFIGURATION
+is defined. */
+#ifndef configOVERRIDE_DEFAULT_TICK_CONFIGURATION
+	#define configOVERRIDE_DEFAULT_TICK_CONFIGURATION 0
+#endif
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG			( * ( ( volatile unsigned long * ) 0xe000e010 ) )
@@ -120,9 +121,11 @@ variable. */
 static unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa;
 
 /*
- * Setup the timer to generate the tick interrupts.
+ * Setup the timer to generate the tick interrupts.  The implementation in this
+ * file is weak to allow application writers to change the timer used to 
+ * generate the tick interrupt.
  */
-static void prvSetupTimerInterrupt( void );
+void vPortSetupTimerInterrupt( void );
 
 /*
  * Exception handlers.
@@ -141,7 +144,9 @@ static void prvStartFirstTask( void );
 /*
  * The number of SysTick increments that make up one tick period.
  */
-static unsigned long ulTimerReloadValueForOneTick = 0;
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulTimerReloadValueForOneTick = 0;
+#endif
 
 /*
  * The maximum number of tick periods that can be suppressed is limited by the
@@ -151,6 +156,14 @@ static unsigned long ulTimerReloadValueForOneTick = 0;
 	static unsigned long xMaximumPossibleSuppressedTicks = 0;
 #endif /* configUSE_TICKLESS_IDLE */
 
+/*
+ * Compensate for the CPU cycles that pass while the SysTick is stopped (low
+ * power functionality only.
+ */
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulStoppedTimerCompensation = 0;
+#endif /* configUSE_TICKLESS_IDLE */
+
 /*-----------------------------------------------------------*/
 
 /*
@@ -219,7 +232,7 @@ portBASE_TYPE xPortStartScheduler( void )
 
 	/* Start the timer that generates the tick ISR.  Interrupts are disabled
 	here already. */
-	prvSetupTimerInterrupt();
+	vPortSetupTimerInterrupt();
 
 	/* Initialise the critical nesting count ready for the first task. */
 	uxCriticalNesting = 0;
@@ -305,6 +318,10 @@ void xPortSysTickHandler( void )
 	}
 	#endif
 
+	/* Only reset the systick load register if configUSE_TICKLESS_IDLE is set to
+	1.  If it is set to 0 tickless idle is not being used.  If it is set to a 
+	value other than 0 or 1 then a timer other than the SysTick is being used
+	to generate the tick interrupt. */
 	#if configUSE_TICKLESS_IDLE == 1
 		portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
 	#endif
@@ -368,9 +385,12 @@ void xPortSysTickHandler( void )
 			portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 
 			/* Sleep until something happens. */
-			configPRE_SLEEP_PROCESSING();
-			__wfi();
-			configPOST_SLEEP_PROCESSING();
+			configPRE_SLEEP_PROCESSING( xExpectedIdleTime );
+			if( xExpectedIdleTime > 0 )
+			{
+				__wfi();
+			}
+			configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
 
 			/* Stop SysTick.  Again, the time the SysTick is stopped for is
 			accounted for as best it can be, but using the tickless mode will
@@ -426,18 +446,25 @@ void xPortSysTickHandler( void )
  * Setup the SysTick timer to generate the tick interrupts at the required
  * frequency.
  */
-void prvSetupTimerInterrupt( void )
-{
-	/* Calculate the constants required to configure the tick interrupt. */
-	ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
-	#if configUSE_TICKLESS_IDLE == 1
-		xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
-	#endif /* configUSE_TICKLESS_IDLE */
+#if configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0
 
-	/* Configure SysTick to interrupt at the requested rate. */
-	portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
-	portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
-}
+	void vPortSetupTimerInterrupt( void )
+	{
+		/* Calculate the constants required to configure the tick interrupt. */		
+		#if configUSE_TICKLESS_IDLE == 1
+		{
+			ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
+			xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
+			ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
+		}
+		#endif /* configUSE_TICKLESS_IDLE */
+	
+		/* Configure SysTick to interrupt at the requested rate. */
+		portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;;
+		portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
+	}
+	
+#endif /* configOVERRIDE_DEFAULT_TICK_CONFIGURATION */
 /*-----------------------------------------------------------*/
 
 __asm unsigned long ulPortSetInterruptMask( void )
@@ -449,7 +476,6 @@ __asm unsigned long ulPortSetInterruptMask( void )
 	msr basepri, r1
 	bx r14
 }
-
 /*-----------------------------------------------------------*/
 
 __asm void vPortClearInterruptMask( unsigned long ulNewMask )
diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c
index 02818c5e2..2c2c4c79a 100644
--- a/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c
+++ b/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c
@@ -84,15 +84,16 @@
 
 #ifndef configSYSTICK_CLOCK_HZ
 	#define configSYSTICK_CLOCK_HZ configCPU_CLOCK_HZ
-	#if configUSE_TICKLESS_IDLE == 1
-		static const unsigned long ulStoppedTimerCompensation = 45UL;
-	#endif
-#else /* configSYSTICK_CLOCK_HZ */
-	#if configUSE_TICKLESS_IDLE == 1
-		/* Assumes the SysTick clock is slower than the CPU clock. */
-		static const unsigned long ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
-	#endif
-#endif	/* configSYSTICK_CLOCK_HZ */
+#endif
+
+/* The __weak attribute does not work as you might expect with the Keil tools
+so the configOVERRIDE_DEFAULT_TICK_CONFIGURATION constant must be set to 1 if
+the application writer wants to provide their own implementation of 
+vPortSetupTimerInterrupt().  Ensure configOVERRIDE_DEFAULT_TICK_CONFIGURATION
+is defined. */
+#ifndef configOVERRIDE_DEFAULT_TICK_CONFIGURATION
+	#define configOVERRIDE_DEFAULT_TICK_CONFIGURATION 0
+#endif
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG			( * ( ( volatile unsigned long * ) 0xe000e010 ) )
@@ -125,9 +126,11 @@ variable. */
 static unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa;
 
 /*
- * Setup the timer to generate the tick interrupts.
+ * Setup the timer to generate the tick interrupts.  The implementation in this
+ * file is weak to allow application writers to change the timer used to 
+ * generate the tick interrupt.
  */
-static void prvSetupTimerInterrupt( void );
+void vPortSetupTimerInterrupt( void );
 
 /*
  * Exception handlers.
@@ -150,7 +153,9 @@ static void prvEnableVFP( void );
 /*
  * The number of SysTick increments that make up one tick period.
  */
-static unsigned long ulTimerReloadValueForOneTick = 0;
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulTimerReloadValueForOneTick = 0;
+#endif
 
 /*
  * The maximum number of tick periods that can be suppressed is limited by the
@@ -160,6 +165,14 @@ static unsigned long ulTimerReloadValueForOneTick = 0;
 	static unsigned long xMaximumPossibleSuppressedTicks = 0;
 #endif /* configUSE_TICKLESS_IDLE */
 
+/*
+ * Compensate for the CPU cycles that pass while the SysTick is stopped (low
+ * power functionality only.
+ */
+#if configUSE_TICKLESS_IDLE == 1
+	static unsigned long ulStoppedTimerCompensation = 0;
+#endif /* configUSE_TICKLESS_IDLE */
+
 /*-----------------------------------------------------------*/
 
 /*
@@ -257,7 +270,7 @@ portBASE_TYPE xPortStartScheduler( void )
 
 	/* Start the timer that generates the tick ISR.  Interrupts are disabled
 	here already. */
-	prvSetupTimerInterrupt();
+	vPortSetupTimerInterrupt();
 
 	/* Initialise the critical nesting count ready for the first task. */
 	uxCriticalNesting = 0;
@@ -368,6 +381,10 @@ void xPortSysTickHandler( void )
 	}
 	#endif
 
+	/* Only reset the systick load register if configUSE_TICKLESS_IDLE is set to
+	1.  If it is set to 0 tickless idle is not being used.  If it is set to a 
+	value other than 0 or 1 then a timer other than the SysTick is being used
+	to generate the tick interrupt. */
 	#if configUSE_TICKLESS_IDLE == 1
 		portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
 	#endif
@@ -431,9 +448,12 @@ void xPortSysTickHandler( void )
 			portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
 
 			/* Sleep until something happens. */
-			configPRE_SLEEP_PROCESSING();
-			__wfi();
-			configPOST_SLEEP_PROCESSING();
+			configPRE_SLEEP_PROCESSING( xExpectedIdleTime );
+			if( xExpectedIdleTime > 0 )
+			{
+				__wfi();
+			}
+			configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
 
 			/* Stop SysTick.  Again, the time the SysTick is stopped for is
 			accounted for as best it can be, but using the tickless mode will
@@ -486,21 +506,28 @@ void xPortSysTickHandler( void )
 /*-----------------------------------------------------------*/
 
 /*
- * Setup the systick timer to generate the tick interrupts at the required
+ * Setup the SysTick timer to generate the tick interrupts at the required
  * frequency.
  */
-void prvSetupTimerInterrupt( void )
-{
-	/* Calculate the constants required to configure the tick interrupt. */
-	ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
-	#if configUSE_TICKLESS_IDLE == 1
-		xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
-	#endif /* configUSE_TICKLESS_IDLE */
+#if configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0
 
-	/* Configure SysTick to interrupt at the requested rate. */
-	portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
-	portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
-}
+	void vPortSetupTimerInterrupt( void )
+	{
+		/* Calculate the constants required to configure the tick interrupt. */		
+		#if configUSE_TICKLESS_IDLE == 1
+		{
+			ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
+			xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
+			ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
+		}
+		#endif /* configUSE_TICKLESS_IDLE */
+	
+		/* Configure SysTick to interrupt at the requested rate. */
+		portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;;
+		portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
+	}
+	
+#endif /* configOVERRIDE_DEFAULT_TICK_CONFIGURATION */
 /*-----------------------------------------------------------*/
 
 __asm unsigned long ulPortSetInterruptMask( void )
@@ -512,7 +539,6 @@ __asm unsigned long ulPortSetInterruptMask( void )
 	msr basepri, r1
 	bx r14
 }
-
 /*-----------------------------------------------------------*/
 
 __asm void vPortClearInterruptMask( unsigned long ulNewMask )
diff --git a/FreeRTOS/Source/tasks.c b/FreeRTOS/Source/tasks.c
index ef6208fc9..a7800fcc1 100644
--- a/FreeRTOS/Source/tasks.c
+++ b/FreeRTOS/Source/tasks.c
@@ -1,7 +1,7 @@
 /*
     FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.
 
-    FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT 
+    FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT
     http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
 
     ***************************************************************************
@@ -42,7 +42,7 @@
     FreeRTOS WEB site.
 
     1 tab == 4 spaces!
-    
+
     ***************************************************************************
      *                                                                       *
      *    Having a problem?  Start by reading the FAQ "My application does   *
@@ -52,17 +52,17 @@
      *                                                                       *
     ***************************************************************************
 
-    
-    http://www.FreeRTOS.org - Documentation, training, latest versions, license 
-    and contact details.  
-    
+
+    http://www.FreeRTOS.org - Documentation, training, latest versions, license
+    and contact details.
+
     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
     including FreeRTOS+Trace - an indispensable productivity tool.
 
-    Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell 
-    the code with commercial support, indemnification, and middleware, under 
+    Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
+    the code with commercial support, indemnification, and middleware, under
     the OpenRTOS brand: http://www.OpenRTOS.com.  High Integrity Systems also
-    provide a safety engineered and independently SIL3 certified version under 
+    provide a safety engineered and independently SIL3 certified version under
     the SafeRTOS brand: http://www.SafeRTOS.com.
 */
 
@@ -463,8 +463,13 @@ static tskTCB *prvAllocateTCBAndStack( unsigned short usStackDepth, portSTACK_TY
 /*
  * Return the amount of time, in ticks, that will pass before the kernel will
  * next move a task from the Blocked state to the Running state.
+ *
+ * This conditional compilation should use inequality to 0, not equality to 1.
+ * This is to ensure portSUPPRESS_TICKS_AND_SLEEP() can be called when user
+ * defined low power mode implementations require configUSE_TICKLESS_IDLE to be
+ * set to a value other than 1.
  */
-#if ( configUSE_TICKLESS_IDLE == 1 )
+#if ( configUSE_TICKLESS_IDLE != 0 )
 
 	static portTickType prvGetExpectedIdleTime( void ) PRIVILEGED_FUNCTION;
 
@@ -1314,28 +1319,32 @@ void vTaskSuspendAll( void )
 }
 /*----------------------------------------------------------*/
 
-portTickType prvGetExpectedIdleTime( void )
-{
-portTickType xReturn;
+#if ( configUSE_TICKLESS_IDLE != 0 )
 
-	if( pxCurrentTCB->uxPriority > tskIDLE_PRIORITY )
+	portTickType prvGetExpectedIdleTime( void )
 	{
-		xReturn = 0;
-	}
-	else if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > 1 )
-	{
-		/* There are other idle priority tasks in the ready state.  If
-		time slicing is used then the very next tick interrupt must be
-		processed. */
-		xReturn = 0;
-	}
-	else
-	{
-		xReturn = xNextTaskUnblockTime - xTickCount;
+	portTickType xReturn;
+	
+		if( pxCurrentTCB->uxPriority > tskIDLE_PRIORITY )
+		{
+			xReturn = 0;
+		}
+		else if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > 1 )
+		{
+			/* There are other idle priority tasks in the ready state.  If
+			time slicing is used then the very next tick interrupt must be
+			processed. */
+			xReturn = 0;
+		}
+		else
+		{
+			xReturn = xNextTaskUnblockTime - xTickCount;
+		}
+	
+		return xReturn;
 	}
 
-	return xReturn;
-}
+#endif /* configUSE_TICKLESS_IDLE != 0  */
 /*----------------------------------------------------------*/
 
 signed portBASE_TYPE xTaskResumeAll( void )
@@ -1627,7 +1636,11 @@ unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
 #endif
 /*----------------------------------------------------------*/
 
-#if ( configUSE_TICKLESS_IDLE == 1 )
+/* This conditional compilation should use inequality to 0, not equality to 1.
+This is to ensure vTaskStepTick() is available when user defined low power mode	
+implementations require configUSE_TICKLESS_IDLE to be set to a value other than
+1. */
+#if ( configUSE_TICKLESS_IDLE != 0 )
 
 	void vTaskStepTick( portTickType xTicksToJump )
 	{
@@ -2146,7 +2159,11 @@ static portTASK_FUNCTION( prvIdleTask, pvParameters )
 		}
 		#endif
 
-		#if ( configUSE_TICKLESS_IDLE == 1 )
+		/* This conditional compilation should use inequality to 0, not equality
+		to 1.  This is to ensure portSUPPRESS_TICKS_AND_SLEEP() is called when
+		user defined low power mode	implementations require
+		configUSE_TICKLESS_IDLE to be set to a value other than 1. */
+		#if ( configUSE_TICKLESS_IDLE != 0 )
 		{
 		portTickType xExpectedIdleTime;
 		/* If the expected idle time is 1 then the idle time would end at
@@ -2156,34 +2173,29 @@ static portTASK_FUNCTION( prvIdleTask, pvParameters )
 		routines returns. */
 		const portTickType xMinimumExpectedIdleTime = ( portTickType ) 2;
 
-			/* Don't enter low power if there are still tasks waiting
-			deletion. */
-			if( uxTasksDeleted == 0 )
+			/* It is not desirable to suspend then resume the scheduler on
+			each iteration of the idle task.  Therefore, a preliminary
+			test of the expected idle time is performed without the
+			scheduler suspended.  The result here is not necessarily
+			valid. */
+			xExpectedIdleTime = prvGetExpectedIdleTime();
+
+			if( xExpectedIdleTime >= xMinimumExpectedIdleTime )
 			{
-				/* It is not desirable to suspend then resume the scheduler on
-				each iteration of the idle task.  Therefore, a preliminary
-				test of the expected idle time is performed without the
-				scheduler suspended.  The result here is not necessarily
-				valid. */
-				xExpectedIdleTime = prvGetExpectedIdleTime();
-
-				if( xExpectedIdleTime >= xMinimumExpectedIdleTime )
+				vTaskSuspendAll();
 				{
-					vTaskSuspendAll();
-					{
-						/* Now the scheduler is suspended, the expected idle
-						time can be sampled again, and this time its value can
-						be used. */
-						configASSERT( xNextTaskUnblockTime >= xTickCount );
-						xExpectedIdleTime = prvGetExpectedIdleTime();
+					/* Now the scheduler is suspended, the expected idle
+					time can be sampled again, and this time its value can
+					be used. */
+					configASSERT( xNextTaskUnblockTime >= xTickCount );
+					xExpectedIdleTime = prvGetExpectedIdleTime();
 
-						if( xExpectedIdleTime >= xMinimumExpectedIdleTime )
-						{
-							portSUPPRESS_TICKS_AND_SLEEP( xExpectedIdleTime );
-						}
+					if( xExpectedIdleTime >= xMinimumExpectedIdleTime )
+					{
+						portSUPPRESS_TICKS_AND_SLEEP( xExpectedIdleTime );
 					}
-					xTaskResumeAll();
 				}
+				xTaskResumeAll();
 			}
 		}
 		#endif
@@ -2328,7 +2340,7 @@ static void prvCheckTasksWaitingTermination( void )
 
 		/* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
 		too often in the idle task. */
-		if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0U )
+		while( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0U )
 		{
 			vTaskSuspendAll();
 				xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
-- 
2.39.2