LPCXpression console on UART3

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3497 42af7a65-404d-4744-a932-0658087f49c3

16 files changed, 224 insertions, 104 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 875ddb834..b5e54083d 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -1673,5 +1673,16 @@
 	  make will fail with an obscure error about not being able to stat pass2.
 	* configs/lpcxpresso-lpc1768/nsh: Add an NSH configuration for the
 	  LPCXpresso board.
+	* configs/*/ld.script: Removed 'sh_link not set for section .ARM.edix' for
+	  a few of the builds.  In you have this warning, it can be removed with the
+	  following change to the ld.script file:
+	  
+		+ __exidx_start = ABSOLUTE(.);
+		.ARM.exidx : {
+		-     __exidx_start = ABSOLUTE(.);
+		      *(.ARM.exidx*)
+		-     __exidx_end = ABSOLUTE(.);
+		} >sram
+		+  __exidx_end = ABSOLUTE(.);
 
 
diff --git a/nuttx/arch/arm/src/lpc17xx/lpc17_lowputc.c b/nuttx/arch/arm/src/lpc17xx/lpc17_lowputc.c
index 83dbd709c..47746ef26 100755
--- a/nuttx/arch/arm/src/lpc17xx/lpc17_lowputc.c
+++ b/nuttx/arch/arm/src/lpc17xx/lpc17_lowputc.c
@@ -1,7 +1,7 @@
 /**************************************************************************
  * arch/arm/src/lpc17xx/lpc17_lowputc.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
@@ -340,7 +340,7 @@ void lpc17_lowsetup(void)
 #elif defined(CONFIG_UART1_SERIAL_CONSOLE)
   lpc17_configgpio(GPIO_UART1_TXD);
   lpc17_configgpio(GPIO_UART1_RXD);
-#ifdef CONFIG_UART0_FLOWCONTROL
+#ifdef CONFIG_UART1_FLOWCONTROL
   lpc17_configgpio(GPIO_UART1_CTS);
   lpc17_configgpio(GPIO_UART1_DCD);
   lpc17_configgpio(GPIO_UART1_DSR);
diff --git a/nuttx/arch/arm/src/lpc17xx/lpc17_serial.c b/nuttx/arch/arm/src/lpc17xx/lpc17_serial.c
index 63687038f..f5c20aca6 100755
--- a/nuttx/arch/arm/src/lpc17xx/lpc17_serial.c
+++ b/nuttx/arch/arm/src/lpc17xx/lpc17_serial.c
@@ -141,12 +141,12 @@ static char g_uart1rxbuffer[CONFIG_UART1_RXBUFSIZE];
 static char g_uart1txbuffer[CONFIG_UART1_TXBUFSIZE];
 #endif
 #ifdef CONFIG_LPC17_UART2
-static char g_uart2rxbuffer[CONFIG_UART1_RXBUFSIZE];
-static char g_uart2txbuffer[CONFIG_UART1_TXBUFSIZE];
+static char g_uart2rxbuffer[CONFIG_UART2_RXBUFSIZE];
+static char g_uart2txbuffer[CONFIG_UART2_TXBUFSIZE];
 #endif
 #ifdef CONFIG_LPC17_UART3
-static char g_uart3rxbuffer[CONFIG_UART1_RXBUFSIZE];
-static char g_uart3txbuffer[CONFIG_UART1_TXBUFSIZE];
+static char g_uart3rxbuffer[CONFIG_UART3_RXBUFSIZE];
+static char g_uart3txbuffer[CONFIG_UART3_TXBUFSIZE];
 #endif
 
 /* This describes the state of the LPC17xx uart0 port. */
@@ -694,7 +694,7 @@ static inline void lpc17_uart2config(uint32_t clkdiv)
   /* Step 2: Enable clocking on UART */
 
   regval = getreg32(LPC17_SYSCON_PCLKSEL1);
-  regval &= ~SYSCON_PCLKSEL0_UART2_MASK;
+  regval &= ~SYSCON_PCLKSEL1_UART2_MASK;
   regval |= (clkdiv << SYSCON_PCLKSEL1_UART2_SHIFT);
   putreg32(regval, LPC17_SYSCON_PCLKSEL1);
 
@@ -722,7 +722,7 @@ static inline void lpc17_uart3config(uint32_t clkdiv)
   /* Step 2: Enable clocking on UART */
 
   regval = getreg32(LPC17_SYSCON_PCLKSEL1);
-  regval &= ~SYSCON_PCLKSEL0_UART3_MASK;
+  regval &= ~SYSCON_PCLKSEL1_UART3_MASK;
   regval |= (clkdiv << SYSCON_PCLKSEL1_UART3_SHIFT);
   putreg32(regval, LPC17_SYSCON_PCLKSEL1);
 
diff --git a/nuttx/configs/lpcxpresso-lpc1768/README.txt b/nuttx/configs/lpcxpresso-lpc1768/README.txt
index 403864aa6..dfa875fa6 100755
--- a/nuttx/configs/lpcxpresso-lpc1768/README.txt
+++ b/nuttx/configs/lpcxpresso-lpc1768/README.txt
@@ -23,7 +23,7 @@ LCPXpresso LPC1768 Board
   -------------------------------- --------- -------------- ---------------------

 

   P0[0]/RD1/TXD3/SDA1               J6-9     I2C E2PROM SDA TXD3/SDA1

-  P0[1]/TD1/RXD3/SCL                J6-10                   RXD2/SCL1

+  P0[1]/TD1/RXD3/SCL                J6-10                   RXD3/SCL1

   P0[2]/TXD0/AD0[7]                 J6-21    

   P0[3]/RXD0/AD0[6]                 J6-22    

   P0[4]/I2SRX-CLK/RD2/CAP2.0        J6-38                   CAN_RX2

@@ -45,7 +45,7 @@ LCPXpresso LPC1768 Board
   P0[23]/AD0[0]/I2SRX_CLK/CAP3[0]   J6-15                   AD0.0

   P0[24]/AD0[1]/I2SRX_WS/CAP3[1]    J6-16                   AD0.1

   P0[25]/AD0[2]/I2SRX_SDA/TXD3      J6-17                   AD0.2

-  P0[26]/AD0[3]/AOUT/RXD3           J6-18                   AD0.3/AOUT

+  P0[26]/AD0[3]/AOUT/RXD3           J6-18                   AD0.3/AOUT / RGB LED

   P0[27]/SDA0/USB_SDA               J6-25                   

   P0[28]/SCL0                       J6-26                   

   P0[29]/USB_D+                     J6-37                   USB_D+

@@ -76,8 +76,8 @@ LCPXpresso LPC1768 Board
   P1[30]/VBUS/AD0[4]                J6-19                   AD0.4

   P1[31]/SCK1/AD0[5]                J6-20                   AD0.5

 

-  P2[0]/PWM1.1/TXD1                 J6-42                   PWM1.1

-  P2[1]/PWM1.2/RXD1                 J6-43                   PWM1.2

+  P2[0]/PWM1.1/TXD1                 J6-42                   PWM1.1 / RGB LED / RS422 RX

+  P2[1]/PWM1.2/RXD1                 J6-43                   PWM1.2 / OLED voltage / RGB LED

   P2[2]/PWM1.3/CTS1/TRACEDATA[3]    J6-44                   PWM1.3

   P2[3]/PWM1.4/DCD1/TRACEDATA[2]    J6-45                   PWM1.4

   P2[4]/PWM1.5/DSR1/TRACEDATA[1]    J6-46                   PWM1.5

@@ -321,44 +321,30 @@ LEDs
 

   - configs/lpcxpresso-lpc1768/src/up_leds.c - LED control logic.

 

-  The LPCXpresso has 3 LEDs... two on the Babel CAN board and a "heartbeat" LED."

-  The LEDs on the Babel CAN board are capabl of OFF/GREEN/RED/AMBER status.

-  In normal usage, the two LEDs on the Babel CAN board would show CAN status, but if

-  CONFIG_ARCH_LEDS is defined, these LEDs will be controlled as follows for NuttX

-  debug functionality (where NC means "No Change").

-

-  During the boot phases.  LED1 and LED2 will show boot status.

-

-                                          /* LED1   LED2   HEARTBEAT */

-    #define LED_STARTED                0  /* OFF    OFF    OFF */

-    #define LED_HEAPALLOCATE           1  /* GREEN  OFF    OFF */

-    #define LED_IRQSENABLED            2  /* OFF    GREEN  OFF */

-    #define LED_STACKCREATED           3  /* OFF    OFF    OFF */

-

-    #define LED_INIRQ                  4  /*  NC     NC    ON  (momentary) */

-    #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

-  lpc17_led2():

-

-    enum lpc17_ledstate_e

-    {

-      LPC17_LEDSTATE_OFF   = 0,

-      LPC17_LEDSTATE_GREEN = 1,

-      LPC17_LEDSTATE_RED   = 2,

-      LPC17_LEDSTATE_AMBER = (LPC17_LEDSTATE_GREEN|LPC17_LEDSTATE_RED),

-    };

-

-    EXTERN void lpc17_led1(enum lpc17_ledstate_e state);

-    EXTERN void lpc17_led2(enum lpc17_ledstate_e state);

-

-  The heartbeat LED is illuminated during all interrupt and signal procressing.

-  Normally, it will glow dimly to inicate that the LPC17xx is taking interrupts.

-  On an assertion PANIC, it will flash at 1Hz.

+  The LPCXpresso LPC1768 has a single LEDs (there are more on the Embedded Artists

+  base board, but those are not controlled by NuttX).  Usage this single LED by NuttX

+  is as follows:

+

+  - The LED is not illuminated until the LPCXpresso completes initialization.

+  

+    If the LED is stuck in the OFF state, this means that the LPCXpresso did not 

+	complete intialization.

+

+  - Each time the OS enters an interrupt (or a signal) it will turn the LED OFF and

+    restores its previous stated upon return from the interrupt (or signal).

+

+	The normal state, after initialization will be a dull glow.  The brightness of

+	the glow will be inversely related to the proportion of time spent within interrupt

+	handling logic.  The glow may decrease in brightness when the system is very

+	busy handling device interrupts and increase in brightness as the system becomes

+	idle.

+

+	Stuck in the OFF state suggests that that the system never completed

+	initialization;  Stuck in the ON state would indicated that the system

+	intialialized, but is not takint interrupts.

+

+  - If a fatal assertion or a fatal unhandled exception occurs, the LED will flash

+    strongly as a slow, 1Hz rate.

 

 LPCXpresso Configuration Options

 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

diff --git a/nuttx/configs/lpcxpresso-lpc1768/include/board.h b/nuttx/configs/lpcxpresso-lpc1768/include/board.h
index 5229c1732..b2b3dcaa6 100755
--- a/nuttx/configs/lpcxpresso-lpc1768/include/board.h
+++ b/nuttx/configs/lpcxpresso-lpc1768/include/board.h
@@ -146,7 +146,7 @@
 /* Pin Description                  Connector On Board       Base Board
  * -------------------------------- --------- -------------- ---------------------
  * P0[0]/RD1/TXD3/SDA1               J6-9     I2C E2PROM SDA TXD3/SDA1
- * P0[1]/TD1/RXD3/SCL                J6-10                   RXD2/SCL1
+ * P0[1]/TD1/RXD3/SCL                J6-10                   RXD3/SCL1
  * P0[2]/TXD0/AD0[7]                 J6-21    
  * P0[3]/RXD0/AD0[6]                 J6-22    
  * P0[4]/I2SRX-CLK/RD2/CAP2.0        J6-38                   CAN_RX2
@@ -168,14 +168,16 @@
  * P0[23]/AD0[0]/I2SRX_CLK/CAP3[0]   J6-15                   AD0.0
  * P0[24]/AD0[1]/I2SRX_WS/CAP3[1]    J6-16                   AD0.1
  * P0[25]/AD0[2]/I2SRX_SDA/TXD3      J6-17                   AD0.2
- * P0[26]/AD0[3]/AOUT/RXD3           J6-18                   AD0.3/AOUT
+ * P0[26]/AD0[3]/AOUT/RXD3           J6-18                   AD0.3/AOUT / RGB LED
  * P0[27]/SDA0/USB_SDA               J6-25                   
  * P0[28]/SCL0                       J6-26                   
  * P0[29]/USB_D+                     J6-37                   USB_D+
  * P0[30]/USB_D-                     J6-36                   USB_D-
  */
 
+#define GPIO_UART3_TXD     GPIO_UART3_TXD_1
 #define GPIO_I2C1_SDA      GPIO_I2C1_SDA_1
+#define GPIO_UART3_RXD     GPIO_UART3_RXD_1
 #define GPIO_I2C1_SCL      GPIO_I2C1_SCL_1
 #define GPIO_SSP1_SCK      GPIO_SSP1_SCK_1
 #define GPIO_UART2_TXD     GPIO_UART2_TXD_1
@@ -216,8 +218,8 @@
 #define GPIO_ENET_MDC      GPIO_ENET_MDC_1
 #define GPIO_ENET_MDIO     GPIO_ENET_MDIO_1
 
-/* P2[0]/PWM1.1/TXD1                 J6-42                   PWM1.1
- * P2[1]/PWM1.2/RXD1                 J6-43                   PWM1.2
+/* P2[0]/PWM1.1/TXD1                 J6-42                   PWM1.1 / RGB LED / RS422 RX
+ * P2[1]/PWM1.2/RXD1                 J6-43                   PWM1.2 / RGB LED / RS422 RX
  * P2[2]/PWM1.3/CTS1/TRACEDATA[3]    J6-44                   PWM1.3
  * P2[3]/PWM1.4/DCD1/TRACEDATA[2]    J6-45                   PWM1.4
  * P2[4]/PWM1.5/DSR1/TRACEDATA[1]    J6-46                   PWM1.5
diff --git a/nuttx/configs/lpcxpresso-lpc1768/nsh/defconfig b/nuttx/configs/lpcxpresso-lpc1768/nsh/defconfig
index 6cc69bbd0..fbcceabfe 100755
--- a/nuttx/configs/lpcxpresso-lpc1768/nsh/defconfig
+++ b/nuttx/configs/lpcxpresso-lpc1768/nsh/defconfig
@@ -108,10 +108,10 @@ CONFIG_LPC17_ETHERNET=y
 CONFIG_LPC17_USBHOST=n
 CONFIG_LPC17_USBOTG=n
 CONFIG_LPC17_USBDEV=n
-CONFIG_LPC17_UART0=y
+CONFIG_LPC17_UART0=n
 CONFIG_LPC17_UART1=n
 CONFIG_LPC17_UART2=n
-CONFIG_LPC17_UART3=n
+CONFIG_LPC17_UART3=y
 CONFIG_LPC17_CAN1=n
 CONFIG_LPC17_CAN2=n
 CONFIG_LPC17_SPI=n
@@ -148,10 +148,10 @@ CONFIG_LPC17_GPDMA=n
 # CONFIG_UARTn_PARTIY - 0=no parity, 1=odd parity, 2=even parity
 # CONFIG_UARTn_2STOP - Two stop bits
 #
-CONFIG_UART0_SERIAL_CONSOLE=y
+CONFIG_UART0_SERIAL_CONSOLE=n
 CONFIG_UART1_SERIAL_CONSOLE=n
 CONFIG_UART2_SERIAL_CONSOLE=n
-CONFIG_UART3_SERIAL_CONSOLE=n
+CONFIG_UART3_SERIAL_CONSOLE=y
 
 CONFIG_UART0_TXBUFSIZE=256
 CONFIG_UART1_TXBUFSIZE=256
diff --git a/nuttx/configs/lpcxpresso-lpc1768/ostest/defconfig b/nuttx/configs/lpcxpresso-lpc1768/ostest/defconfig
index 3753766d4..d711f7eb1 100755
--- a/nuttx/configs/lpcxpresso-lpc1768/ostest/defconfig
+++ b/nuttx/configs/lpcxpresso-lpc1768/ostest/defconfig
@@ -108,10 +108,10 @@ CONFIG_LPC17_ETHERNET=n
 CONFIG_LPC17_USBHOST=n
 CONFIG_LPC17_USBOTG=n
 CONFIG_LPC17_USBDEV=n
-CONFIG_LPC17_UART0=y
+CONFIG_LPC17_UART0=n
 CONFIG_LPC17_UART1=n
 CONFIG_LPC17_UART2=n
-CONFIG_LPC17_UART3=n
+CONFIG_LPC17_UART3=y
 CONFIG_LPC17_CAN1=n
 CONFIG_LPC17_CAN2=n
 CONFIG_LPC17_SPI=n
@@ -148,10 +148,10 @@ CONFIG_LPC17_GPDMA=n
 # CONFIG_UARTn_PARTIY - 0=no parity, 1=odd parity, 2=even parity
 # CONFIG_UARTn_2STOP - Two stop bits
 #
-CONFIG_UART0_SERIAL_CONSOLE=y
+CONFIG_UART0_SERIAL_CONSOLE=n
 CONFIG_UART1_SERIAL_CONSOLE=n
 CONFIG_UART2_SERIAL_CONSOLE=n
-CONFIG_UART3_SERIAL_CONSOLE=n
+CONFIG_UART3_SERIAL_CONSOLE=y
 
 CONFIG_UART0_TXBUFSIZE=256
 CONFIG_UART1_TXBUFSIZE=256
diff --git a/nuttx/configs/lpcxpresso-lpc1768/tools/flash.sh b/nuttx/configs/lpcxpresso-lpc1768/tools/flash.sh
index 4d9f0b777..6d3f890a7 100755
--- a/nuttx/configs/lpcxpresso-lpc1768/tools/flash.sh
+++ b/nuttx/configs/lpcxpresso-lpc1768/tools/flash.sh
@@ -44,34 +44,32 @@ echo "  - LPC17xx"
 echo ""
 echo "You will need to edit this is any of the above are false"
 
-# This is the default install location for binaries on Linux
-#BINDIR=/usr/local/LPCXpresso/bin/dfu-util
-
 # This is the default install location for binaries on Windows (note that this
-# path could change with the Code Red version number
-BINDIR=/cygdrive/c/nxp/lpcxpresso_3.6/bin
-
-# This is the default install location for DFUAPP.exe on Windows
-DFUAPP="$BINDIR/DFUAPP.exe"
-
-# ROM image for resetting LPC-Link
-# ROM=LPCXpressoWIN.enc # WinUSB
-# ROM=LPCXpressoFS.enc # Win2000
-# ROM=LPCXpressoFS.enc # WinXP
-# ROM=LPCXpressoFS.enc # Win2003
-# ROM=LPCXpressoHS.enc # WinVista
-ROM=LPCXpressoHS.enc # Win7
-
-ROMPATH=`cygpath -w "$BINDIR/$ROM"`
-
-# FLASHUTIL="$BINDIR/crt_emu_lpc11_13" # for LPC11xx or LPC13xx parts)
-FLASHUTIL="$BINDIR/crt_emu_cm3_nxp"  # for LPC17xx parts
-# FLASHUTIL="$BINDIR/crt_emu_a7_nxp"   # for LPC21/22/23/24 parts)
-# FLASHUTIL="$BINDIR/crt_emu_a9_nxp"   # for LPC31/32 and LPC29xx parts)
-# FLASHUTIL="$BINDIR/crt_emu_cm3_lmi"  # for TI Stellaris LM3S parts
-
-if [ ! -x "$FLASHUTIL" ]; then
-	echo "No executable file at ${FLASHUTIL}"
+# path could change with the Code Red version number)
+BINDIR="/cygdrive/c/nxp/lpcxpresso_3.6/bin"
+if [ ! -d "${BINDIR}" ]; then
+	echo "Directory ${BINDIR} does not exist"
+	exit 1
+fi
+
+# This is the relative path to the booLPCXpresso utility
+BOOTLPC="Scripts/bootLPCXpresso.cmd"
+if [ ! -x "${BINDIR}/$BOOTLPC" ]; then
+	echo "No executable at ${BINDIR}/${BOOTLPC}"
+	exit 1
+fi
+
+# BOOTLPC_ARG=winusb # WinXP
+BOOTLPC_ARG=hid      # Win7
+
+# FLASHUTIL="crt_emu_lpc11_13" # for LPC11xx or LPC13xx parts)
+FLASHUTIL="crt_emu_cm3_nxp"  # for LPC17xx parts
+# FLASHUTIL="crt_emu_a7_nxp"   # for LPC21/22/23/24 parts)
+# FLASHUTIL="crt_emu_a9_nxp"   # for LPC31/32 and LPC29xx parts)
+# FLASHUTIL="crt_emu_cm3_lmi"  # for TI Stellaris LM3S parts
+
+if [ ! -x "${BINDIR}/${FLASHUTIL}" ]; then
+	echo "No executable file at ${BINDIR}/${FLASHUTIL}"
 	exit 1
 fi
 
@@ -79,10 +77,9 @@ fi
 # WIRE="-wire=hi"     # for RDB1768v2 without upgraded firmware)
 # WIRE="-wire=winusb" # for RDB1768v2 with upgraded firmware)
 # WIRE="-wire=winusb" # for LPC-Link on Windows XP)
-WIRE="-wire=hid"      # for LPC-Link on Windows Vista/ Windows 7)
+WIRE="-wire=hid"      # for LPC-Link on Windows Vista/Windows 7)
 
 TARGET=LPC1768
-#TARGET=NXP_dir_part_LPC17
 
 # The nuttx directory must be provided as an argument
 
@@ -115,13 +112,15 @@ else
 		mv ${NUTTX}/nuttx ${NUTTX}/nuttx.axf
 	fi
 fi
+NUTTXPATH=`cygpath -w "${NUTTX}/nuttx.axf"`
 
 # First of all boot the LPC-Link using the script:
 
-#${DFUAPP} /f ${ROMPATH} /tl 250 dfuapp.log
+cd ${BINDIR} || \
+	{ echo "Failed to CD to ${BINDIR}"; exit 1; }
+./${BOOTLPC} ${BOOTLPC_ARG} || \
+	{ echo "'${BOOTLPC} ${BOOTLPC_ARG}' Failed"; }
 
 # Then program the FLASH
 
-#${FLASHUTIL} ${WIRE} -p${TARGET} -flash-load="${NUTTX}/nuttx.axf"
-${FLASHUTIL} -p${TARGET} -flash-load="${NUTTX}/nuttx.axf"
-
+./${FLASHUTIL} ${WIRE} -p${TARGET} -flash-load-exec="${NUTTXPATH}"
diff --git a/nuttx/include/errno.h b/nuttx/include/errno.h
index d0c80975a..94a8b669c 100644
--- a/nuttx/include/errno.h
+++ b/nuttx/include/errno.h
@@ -346,7 +346,7 @@ extern "C" {
 #define EXTERN extern
 #endif
 
-/* Return a pointer to the thread specifid errno.  NOTE:  When doing a
+/* Return a pointer to the thread specific errno.  NOTE:  When doing a
  * kernel-/user-mode build, this function can only be used within the
  * kernel-mode space.
  *
diff --git a/nuttx/include/nuttx/clock.h b/nuttx/include/nuttx/clock.h
index 68f3a46f2..3cd3e36f8 100644
--- a/nuttx/include/nuttx/clock.h
+++ b/nuttx/include/nuttx/clock.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * include/nuttx/clock.h
  *
- *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -96,15 +96,24 @@
 #define TICK2DSEC(tick)       (((tick)+(TICK_PER_DSEC/2))/TICK_PER_DSEC) /* Rounds */
 #define TICK2SEC(tick)        (((tick)+(TICK_PER_SEC/2))/TICK_PER_SEC)   /* Rounds */
 
-
 /****************************************************************************
  * Global Data
  ****************************************************************************/
 
 /* Access to raw system clock ***********************************************/
+/* Direct access to the system timer/counter is supported only if (1) the
+ * system clock is not disabled and (2) the executation environement has 
+ * direct access to kernel global data.
+ *
+ * The code in this execution context can access the kernel global data
+ * directly if:  (1) this is an un-protected, non-kernel build, or (2)
+ * this code is being built for execution within the kernel.
+ */
 
-#ifndef CONFIG_DISABLE_CLOCK
+#if !defined(CONFIG_DISABLE_CLOCK) && \
+   (!defined(CONFIG_NUTTX_KERNEL) || defined(__KERNEL__))
 extern volatile uint32_t g_system_timer;
+#define os_systime32() g_system_timer
 #endif
 
 /****************************************************************************
@@ -122,6 +131,15 @@ extern "C" {
 #define EXTERN extern
 #endif
 
+/* If direct access to the system timer/counter is not supported (see above),
+ * then the value can be obtained via os_systime32 through a system call.
+ */
+
+#if !defined(CONFIG_DISABLE_CLOCK) && \
+     defined(CONFIG_NUTTX_KERNEL) && !defined(__KERNEL__)
+EXTERN uint32_t os_systime32(void);
+#endif
+
 #undef EXTERN
 #ifdef __cplusplus
 }
diff --git a/nuttx/include/sys/syscall.h b/nuttx/include/sys/syscall.h
index d1f123bd8..1f1e37f36 100644
--- a/nuttx/include/sys/syscall.h
+++ b/nuttx/include/sys/syscall.h
@@ -134,11 +134,12 @@
  */
 
 #ifndef CONFIG_DISABLE_CLOCK
-#  define SYS_clock_getres             (__SYS_clock+0)
-#  define SYS_clock_gettime            (__SYS_clock+1)
-#  define SYS_clock_settime            (__SYS_clock+2)
-#  define SYS_gettimeofday             (__SYS_clock+3)
-#  define __SYS_timers                 (__SYS_clock+4)
+#  define SYS_os_systime32             (__SYS_clock+0)
+#  define SYS_clock_getres             (__SYS_clock+1)
+#  define SYS_clock_gettime            (__SYS_clock+2)
+#  define SYS_clock_settime            (__SYS_clock+3)
+#  define SYS_gettimeofday             (__SYS_clock+4)
+#  define __SYS_timers                 (__SYS_clock+5)
 #else
 #  define __SYS_timers                 __SYS_clock
 #endif
diff --git a/nuttx/sched/Makefile b/nuttx/sched/Makefile
index 93807b695..9cd8e5588 100644
--- a/nuttx/sched/Makefile
+++ b/nuttx/sched/Makefile
@@ -54,9 +54,11 @@ SCHED_SRCS	= sched_setparam.c sched_setpriority.c sched_getparam.c \
 		  sched_setscheduler.c sched_getscheduler.c \
 		  sched_yield.c sched_rrgetinterval.c sched_foreach.c \
 		  sched_lock.c sched_unlock.c sched_lockcount.c sched_self.c
+
 ifeq ($(CONFIG_PRIORITY_INHERITANCE),y)
 SCHED_SRCS	+= sched_reprioritize.c 
 endif
+
 ifeq ($(CONFIG_SCHED_WAITPID),y)
 SCHED_SRCS	+= sched_waitpid.c
 endif
@@ -73,10 +75,15 @@ TIME_SRCS	= sched_processtimer.c
 ifneq ($(CONFIG_DISABLE_SIGNALS),y)
 TIME_SRCS	+= sleep.c usleep.c
 endif
+
 CLOCK_SRCS	= clock_initialize.c clock_settime.c clock_gettime.c clock_getres.c \
 		  clock_time2ticks.c clock_abstime2ticks.c clock_ticks2time.c \
 		  clock_gettimeofday.c
 
+ifeq ($(CONFIG_NUTTX_KERNEL),y)
+CLOCK_SRCS	+= clock_systime32.c
+endif
+
 SIGNAL_SRCS	= sig_initialize.c \
 		  sig_action.c sig_procmask.c sig_pending.c sig_suspend.c \
 		  sig_kill.c sig_queue.c sig_waitinfo.c sig_timedwait.c \
@@ -88,9 +95,11 @@ SIGNAL_SRCS	= sig_initialize.c \
 MQUEUE_SRCS	= mq_open.c mq_close.c mq_unlink.c mq_send.c mq_timedsend.c\
 		  mq_sndinternal.c mq_receive.c mq_timedreceive.c mq_rcvinternal.c \
 		  mq_initialize.c mq_descreate.c mq_findnamed.c mq_msgfree.c mq_msgqfree.c
+
 ifneq ($(CONFIG_DISABLE_SIGNALS),y)
 MQUEUE_SRCS	+= mq_waitirq.c
 endif
+
 ifneq ($(CONFIG_DISABLE_SIGNALS),y)
 MQUEUE_SRCS	+= mq_notify.c
 endif
@@ -106,15 +115,18 @@ PTHREAD_SRCS = pthread_create.c pthread_exit.c pthread_join.c pthread_detach.c \
 		  pthread_keycreate.c pthread_setspecific.c pthread_getspecific.c pthread_keydelete.c \
 		  pthread_initialize.c pthread_completejoin.c pthread_findjoininfo.c \
 		  pthread_removejoininfo.c pthread_once.c pthread_setschedprio.c
+
 ifneq ($(CONFIG_DISABLE_SIGNALS),y)
 PTHREAD_SRCS	+= pthread_condtimedwait.c pthread_kill.c pthread_sigmask.c
 endif
 
 SEM_SRCS	= sem_initialize.c sem_destroy.c sem_open.c sem_close.c sem_unlink.c \
 		  sem_wait.c sem_trywait.c sem_post.c sem_findnamed.c
+
 ifneq ($(CONFIG_DISABLE_SIGNALS),y)
 SEM_SRCS	+= sem_waitirq.c
 endif
+
 ifeq ($(CONFIG_PRIORITY_INHERITANCE),y)
 SEM_SRCS	+= sem_holder.c
 endif
@@ -143,18 +155,23 @@ CSRCS		= $(MISC_SRCS) $(TSK_SRCS) $(SCHED_SRCS) $(WDOG_SRCS) $(TIME_SRCS) \
 ifneq ($(CONFIG_DISABLE_CLOCK),y)
 CSRCS		+= $(CLOCK_SRCS)
 endif
+
 ifneq ($(CONFIG_DISABLE_PTHREAD),y)
 CSRCS		+= $(PTHREAD_SRCS)
 endif
+
 ifneq ($(CONFIG_DISABLE_SIGNALS),y)
 CSRCS		+= $(SIGNAL_SRCS)
 endif
+
 ifneq ($(CONFIG_DISABLE_MQUEUE),y)
 CSRCS		+= $(MQUEUE_SRCS)
 endif
+
 ifneq ($(CONFIG_DISABLE_ENVIRON),y)
 CSRCS		+= $(ENV_SRCS)
 endif
+
 ifeq ($(CONFIG_NUTTX_KERNEL),y)
 CSRCS		+= $(KMM_SRCS)
 endif
diff --git a/nuttx/sched/clock_systime32.c b/nuttx/sched/clock_systime32.c
new file mode 100644
index 000000000..f8709e551
--- /dev/null
+++ b/nuttx/sched/clock_systime32.c
@@ -0,0 +1,83 @@
+/****************************************************************************
+ * sched/clock_systime32.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 <nuttx/config.h>
+
+#include <stdint.h>
+#include <nuttx/clock.h>
+
+#if !defined(CONFIG_DISABLE_CLOCK) && \
+     defined(CONFIG_NUTTX_KERNEL) && !defined(__KERNEL__)
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#undef os_systime32
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  os_systime32
+ *
+ * Description:
+ *   Return the current value of the system timer counter
+ *
+ * Parameters:
+ *   None
+ *
+ * Return Value:
+ *   The current value of the system timer counter
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+uint32_t os_systime32(void)
+{
+  return g_system_timer;
+}
+#endif
+
diff --git a/nuttx/syscall/stub_lookup.c b/nuttx/syscall/stub_lookup.c
index 8743e2fda..e46127b14 100644
--- a/nuttx/syscall/stub_lookup.c
+++ b/nuttx/syscall/stub_lookup.c
@@ -107,6 +107,7 @@ extern uintptr_t STUB_usleep(uintptr_t parm1);
  * NuttX configuration.
  */
 
+extern uintptr_t STUB_os_systime32(void);
 extern uintptr_t STUB_clock_getres(uintptr_t parm1, uintptr_t parm2);
 extern uintptr_t STUB_clock_gettime(uintptr_t parm1, uintptr_t parm2);
 extern uintptr_t STUB_clock_settime(uintptr_t parm1, uintptr_t parm2);
diff --git a/nuttx/syscall/stub_lookup.h b/nuttx/syscall/stub_lookup.h
index 31b4c755d..9a56d0d41 100644
--- a/nuttx/syscall/stub_lookup.h
+++ b/nuttx/syscall/stub_lookup.h
@@ -102,6 +102,7 @@ STUB_LOOKUP(3, STUB_up_assert_code)             /* SYS_up_assert_code */
  */
 
 #ifndef CONFIG_DISABLE_CLOCK
+  STUB_LOOKUP(0, STUB_os_systime32)             /* SYS_os_systime32 */
   STUB_LOOKUP(2, STUB_clock_getres)             /* SYS_clock_getres */
   STUB_LOOKUP(2, STUB_clock_gettime)            /* SYS_clock_gettime */
   STUB_LOOKUP(2, STUB_clock_settime)            /* SYS_clock_settime */
diff --git a/nuttx/syscall/syscall.csv b/nuttx/syscall/syscall.csv
index 2510f87d8..a6db07397 100644
--- a/nuttx/syscall/syscall.csv
+++ b/nuttx/syscall/syscall.csv
@@ -39,6 +39,7 @@
 "open","fcntl.h","CONFIG_NFILE_DESCRIPTORS > 0","int","const char*","int","..."
 "opendir","dirent.h","CONFIG_NFILE_DESCRIPTORS > 0","FAR DIR*","FAR const char*"
 "pipe","unistd.h","CONFIG_NFILE_DESCRIPTORS > 0","int","int [2]|int*"
+"os_systime32","nuttx/clock.h","!defined(CONFIG_DISABLE_CLOCK)","uint32_t"
 "poll","poll.h","!defined(CONFIG_DISABLE_POLL) && (CONFIG_NSOCKET_DESCRIPTORS > 0 || CONFIG_NFILE_DESCRIPTORS > 0)","int","FAR struct pollfd*","nfds_t","int"
 "pthread_barrier_destroy","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","FAR pthread_barrier_t*"
 "pthread_barrier_init","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","FAR pthread_barrier_t*","FAR const pthread_barrierattr_t*","unsigned int"