More logic for the AVR port

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3684 42af7a65-404d-4744-a932-0658087f49c3

19 files changed, 2701 insertions, 17 deletions

diff --git a/nuttx/arch/avr/src/at90usb/Make.defs b/nuttx/arch/avr/src/at90usb/Make.defs
index dcff056b5..e3559c0dc 100644
--- a/nuttx/arch/avr/src/at90usb/Make.defs
+++ b/nuttx/arch/avr/src/at90usb/Make.defs
@@ -42,10 +42,11 @@ HEAD_ASRC	= at90usb_head.S
 CMN_ASRCS	= up_switchcontext.S
 CMN_CSRCS	= up_allocateheap.c up_assert.c up_blocktask.c up_copystate.c \
 			  up_createstack.c up_doirq.c up_exit.c  up_idle.c up_initialize.c \
-			  up_interruptcontext.c up_lowputs.c up_mdelay.c up_modifyreg8.c \
-			  up_modifyreg16.c up_modifyreg32.c up_puts.c up_releasepending.c \
-			  up_releasestack.c up_reprioritizertr.c up_schedulesigaction.c \
-			  up_sigdeliver.c up_udelay.c up_unblocktask.c up_usestack.c
+			  up_initialstate.c up_interruptcontext.c up_irq.c up_lowputs.c \
+			  up_mdelay.c up_modifyreg8.c up_modifyreg16.c up_modifyreg32.c \
+			  up_puts.c up_releasepending.c up_releasestack.c \
+			  up_reprioritizertr.c up_schedulesigaction.c up_sigdeliver.c \
+			  up_udelay.c up_unblocktask.c up_usestack.c
 
 # Configuration-dependent common files
 
@@ -56,7 +57,7 @@ endif
 # Required AT90USB files
 
 CHIP_ASRCS	= at90usb_exceptions.S
-CHIP_CSRCS	= 
+CHIP_CSRCS	= at90usb_lowconsole.c at90usb_lowinit.c at90usb_serial.c at90usb_timerisr.c
 
 # Configuration-dependent aT90USB files
 
diff --git a/nuttx/arch/avr/src/at90usb/at90usb_config.h b/nuttx/arch/avr/src/at90usb/at90usb_config.h
index a39a6b5e2..be3cd54f1 100644
--- a/nuttx/arch/avr/src/at90usb/at90usb_config.h
+++ b/nuttx/arch/avr/src/at90usb/at90usb_config.h
@@ -45,6 +45,23 @@
 /************************************************************************************
  * Pre-processor Definitions
  ************************************************************************************/
+/* USARTs ***************************************************************************/
+
+#undef HAVE_USART_DEVICE
+#if defined(CONFIG_AVR_USART1)
+#  define HAVE_USART_DEVICE 1
+#endif
+
+/* Is there a serial console?  There should be at most one defined.  It
+ * could be on any USARTn (but n=1 only for the AT90USB).
+ */
+
+#if defined(CONFIG_USART1_SERIAL_CONSOLE) && defined(CONFIG_AVR_USART1)
+#  define HAVE_SERIAL_CONSOLE 1
+#else
+#  undef CONFIG_USART1_SERIAL_CONSOLE
+#  undef HAVE_SERIAL_CONSOLE
+#endif
 
 /************************************************************************************
  * Public Types
diff --git a/nuttx/arch/avr/src/at90usb/at90usb_head.S b/nuttx/arch/avr/src/at90usb/at90usb_head.S
index f951bac1d..608595f90 100755
--- a/nuttx/arch/avr/src/at90usb/at90usb_head.S
+++ b/nuttx/arch/avr/src/at90usb/at90usb_head.S
@@ -66,6 +66,7 @@
  ****************************************************************************/

 

 	.file	"up_nommuhead.S"

+	.global	__start				/* Entry point */

 	.global	_sbss				/* Start of .bss.  Defined by ld.script */

 	.global	_ebss				/* End of .bss.  Defined by ld.script */

 	.global	_sdata				/* Start of .data section in RAM */

@@ -248,9 +249,13 @@ __do_clear_bss:
 	cpc		r27, r17

 	brne	.Lclearloop

 

+	/* Perform any low-level initialization */

+

+	call	up_lowinit

+

 	/* Now start NuttX */

 

-	call	os_start		/* Start NuttX */

+	call	os_start

 	jmp		exit

 	.endfunc

 

diff --git a/nuttx/arch/avr/src/at90usb/at90usb_lowconsole.c b/nuttx/arch/avr/src/at90usb/at90usb_lowconsole.c
new file mode 100644
index 000000000..f17d79417
--- /dev/null
+++ b/nuttx/arch/avr/src/at90usb/at90usb_lowconsole.c
@@ -0,0 +1,169 @@
+/******************************************************************************
+ * arch/avr/src/at90usb/at90usb_lowconsole.c
+ *
+ *   Copyright (C) 2010 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 "at90usb_config.h"
+
+#include <assert.h>
+#include <debug.h>
+
+#include <arch/irq.h>
+#include <arch/board/board.h>
+
+#include "up_arch.h"
+#include "up_internal.h"
+
+#include "at90usb_internal.h"
+
+/******************************************************************************
+ * Private Definitions
+ ******************************************************************************/
+
+/* Select USART parameters for the selected console -- there is only USART1 */
+
+#if defined(CONFIG_USART1_SERIAL_CONSOLE)
+#  define AVR_CONSOLE_BASE     AVR_USART1_BASE
+#  define AVR_CONSOLE_BAUD     CONFIG_USART1_BAUD
+#  define AVR_CONSOLE_BITS     CONFIG_USART1_BITS
+#  define AVR_CONSOLE_PARITY   CONFIG_USART1_PARITY
+#  define AVR_CONSOLE_2STOP    CONFIG_USART1_2STOP
+#else
+#  error "No CONFIG_USARTn_SERIAL_CONSOLE Setting"
+#endif
+
+/******************************************************************************
+ * Private Types
+ ******************************************************************************/
+
+/******************************************************************************
+ * Private Function Prototypes
+ ******************************************************************************/
+
+/******************************************************************************
+ * Global Variables
+ ******************************************************************************/
+
+/******************************************************************************
+ * Private Variables
+ ******************************************************************************/
+
+/******************************************************************************
+ * Private Functions
+ ******************************************************************************/
+
+/******************************************************************************
+ * Name: usart_setbaudrate
+ *
+ * Description:
+ *   Configure the USART baud rate.
+ *
+ ******************************************************************************/
+
+#ifdef HAVE_USART_DEVICE
+static void usart_setbaudrate(uintptr_t usart_base, uint32_t baudrate)
+{
+# warning "Missing logic"
+}
+#endif
+
+/******************************************************************************
+ * Public Functions
+ ******************************************************************************/
+
+/******************************************************************************
+ * Name: usart_reset
+ *
+ * Description:
+ *   Reset a USART.
+ *
+ ******************************************************************************/
+
+#ifdef HAVE_USART_DEVICE
+void usart_reset(uintptr_t usart_base)
+{
+# warning "Missing Logic"
+}
+#endif
+
+/******************************************************************************
+ * Name: usart_configure
+ *
+ * Description:
+ *   Configure a USART as a RS-232 USART.
+ *
+ ******************************************************************************/
+
+#ifdef HAVE_USART_DEVICE
+void usart_configure(uintptr_t usart_base, uint32_t baud, unsigned int parity,
+                     unsigned int nbits, bool stop2)
+{
+# warning "Missing Logic"
+}
+#endif
+
+/******************************************************************************
+ * Name: up_consoleinit
+ *
+ * Description:
+ *   Initialize a console for debug output.  This function is called very
+ *   early in the intialization sequence to configure the serial console uart
+ *   (only).
+ *
+ ******************************************************************************/
+
+void up_consoleinit(void)
+{
+# warning "Missing Logic"
+}
+
+/******************************************************************************
+ * Name: up_lowputc
+ *
+ * Description:
+ *   Output one byte on the serial console
+ *
+ ******************************************************************************/
+
+void up_lowputc(char ch)
+{
+#ifdef HAVE_SERIAL_CONSOLE
+# warning "Missing Logic"
+#endif
+}
+
diff --git a/nuttx/arch/avr/src/at90usb/at90usb_lowinit.c b/nuttx/arch/avr/src/at90usb/at90usb_lowinit.c
new file mode 100644
index 000000000..f7e7cfb69
--- /dev/null
+++ b/nuttx/arch/avr/src/at90usb/at90usb_lowinit.c
@@ -0,0 +1,103 @@
+/**************************************************************************
+ * arch/avr/src/at90usb/at90usb_lowinit.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 "at90usb_config.h"
+#include "up_internal.h"
+#include "at90usb_internal.h"
+
+/**************************************************************************
+ * Private Definitions
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Types
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Function Prototypes
+ **************************************************************************/
+
+/**************************************************************************
+ * Global Variables
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Variables
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Functions
+ **************************************************************************/
+
+/**************************************************************************
+ * Public Functions
+ **************************************************************************/
+
+/**************************************************************************
+ * Name: up_lowinit
+ *
+ * Description:
+ *   This performs basic initialization of the USART used for the serial
+ *   console.  Its purpose is to get the console output availabe as soon
+ *   as possible.
+ *
+ **************************************************************************/
+
+void up_lowinit(void)
+{
+  /* Initialize a console (probably a serial console) */
+
+  up_consoleinit();
+
+  /* Perform early serial initialization (so that we will have debug output
+   * available as soon as possible).
+   */
+
+#ifdef CONFIG_USE_EARLYSERIALINIT
+  up_earlyserialinit();
+#endif
+
+  /* Perform board-level initialization */
+
+  up_boardinitialize();
+}
+
+
diff --git a/nuttx/arch/avr/src/at90usb/at90usb_serial.c b/nuttx/arch/avr/src/at90usb/at90usb_serial.c
new file mode 100644
index 000000000..939c707a7
--- /dev/null
+++ b/nuttx/arch/avr/src/at90usb/at90usb_serial.c
@@ -0,0 +1,664 @@
+/****************************************************************************
+ * arch/avr/src/at90usb/at90usb_serial.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 "at90usb_config.h"
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <semaphore.h>
+#include <string.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/irq.h>
+#include <nuttx/arch.h>
+#include <nuttx/serial.h>
+
+#include <arch/board/board.h>
+
+#include "up_arch.h"
+#include "up_internal.h"
+#include "os_internal.h"
+#include "at90usb_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/* Some sanity checks *******************************************************/
+
+/* Is there at least one USART enabled and configured as a RS-232 device? */
+
+#ifndef HAVE_USART_DEVICE
+#  warning "No USARTs enabled as RS-232 devices"
+#endif
+
+/* If we are not using the serial driver for the console, then we still must
+ * provide some minimal implementation of up_putc.
+ */
+
+#ifdef CONFIG_USE_SERIALDRIVER
+
+/* Which USART with be tty0/console and which tty1? */
+
+#if defined(CONFIG_USART1_SERIAL_CONSOLE)
+#  define CONSOLE_DEV     g_usart1port     /* USART1 is console */
+#  define TTYS0_DEV       g_usart1port     /* USART1 is ttyS0 */
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct up_dev_s
+{
+  uintptr_t usartbase; /* Base address of USART registers */
+  uint32_t  baud;      /* Configured baud */
+  uint32_t  csr;       /* Saved channel status register contents */
+  uint8_t   irq;       /* IRQ associated with this USART */
+  uint8_t   parity;    /* 0=none, 1=odd, 2=even */
+  uint8_t   bits;      /* Number of bits (5, 6, 7 or 8) */
+  bool      stopbits2; /* true: Configure with 2 stop bits instead of 1 */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int  up_setup(struct uart_dev_s *dev);
+static void up_shutdown(struct uart_dev_s *dev);
+static int  up_attach(struct uart_dev_s *dev);
+static void up_detach(struct uart_dev_s *dev);
+static int  up_interrupt(int irq, void *context);
+static int  up_ioctl(struct file *filep, int cmd, unsigned long arg);
+static int  up_receive(struct uart_dev_s *dev, uint32_t *status);
+static void up_rxint(struct uart_dev_s *dev, bool enable);
+static bool up_rxavailable(struct uart_dev_s *dev);
+static void up_send(struct uart_dev_s *dev, int ch);
+static void up_txint(struct uart_dev_s *dev, bool enable);
+static bool up_txready(struct uart_dev_s *dev);
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+struct uart_ops_s g_uart_ops =
+{
+  .setup          = up_setup,
+  .shutdown       = up_shutdown,
+  .attach         = up_attach,
+  .detach         = up_detach,
+  .ioctl          = up_ioctl,
+  .receive        = up_receive,
+  .rxint          = up_rxint,
+  .rxavailable    = up_rxavailable,
+  .send           = up_send,
+  .txint          = up_txint,
+  .txready        = up_txready,
+  .txempty        = up_txready,
+};
+
+/* I/O buffers */
+
+#ifdef CONFIG_AVR_USART1_RS232
+static char g_usart1rxbuffer[CONFIG_USART1_RXBUFSIZE];
+static char g_usart1txbuffer[CONFIG_USART1_TXBUFSIZE];
+#endif
+
+/* This describes the state of the AVR32 USART1 port. */
+
+#ifdef CONFIG_AVR_USART1_RS232
+static struct up_dev_s g_usart1priv =
+{
+  .usartbase      = AVR_USART1_BASE,
+  .baud           = CONFIG_USART1_BAUD,
+  .irq            = AVR_IRQ_USART1,
+  .parity         = CONFIG_USART1_PARITY,
+  .bits           = CONFIG_USART1_BITS,
+  .stopbits2      = CONFIG_USART1_2STOP,
+};
+
+static uart_dev_t g_usart1port =
+{
+  .recv     =
+  {
+    .size   = CONFIG_USART1_RXBUFSIZE,
+    .buffer = g_usart1rxbuffer,
+  },
+  .xmit     =
+  {
+    .size   = CONFIG_USART1_TXBUFSIZE,
+    .buffer = g_usart1txbuffer,
+   },
+  .ops      = &g_uart_ops,
+  .priv     = &g_usart1priv,
+};
+#endif
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_serialin
+ ****************************************************************************/
+
+static inline uint32_t up_serialin(struct up_dev_s *priv, int offset)
+{
+# warning "Missing logic"
+}
+
+/****************************************************************************
+ * Name: up_serialout
+ ****************************************************************************/
+
+static inline void up_serialout(struct up_dev_s *priv, int offset, uint32_t value)
+{
+# warning "Missing logic"
+}
+
+/****************************************************************************
+ * Name: up_restoreusartint
+ ****************************************************************************/
+
+static void up_restoreusartint(struct up_dev_s *priv, uint32_t imr)
+{
+# warning "Missing logic"
+}
+
+/****************************************************************************
+ * Name: up_disableusartint
+ ****************************************************************************/
+
+static inline void up_disableusartint(struct up_dev_s *priv, uint32_t *imr)
+{
+# warning "Missing logic"
+}
+
+/****************************************************************************
+ * Name: up_setup
+ *
+ * Description:
+ *   Configure the USART baud, bits, parity, etc. This method is called the
+ *   first time that the serial port is opened.
+ *
+ ****************************************************************************/
+
+static int up_setup(struct uart_dev_s *dev)
+{
+#ifndef CONFIG_SUPPRESS_UART_CONFIG
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  /* Configure the USART as an RS-232 UART */
+
+  usart_configure(priv->usartbase, priv->baud, priv->parity,
+                  priv->bits, priv->stopbits2);
+#endif
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: up_shutdown
+ *
+ * Description:
+ *   Disable the USART.  This method is called when the serial
+ *   port is closed
+ *
+ ****************************************************************************/
+
+static void up_shutdown(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  /* Reset, disable interrupts, and disable Rx and Tx */
+
+  usart_reset(priv->usartbase);
+}
+
+/****************************************************************************
+ * Name: up_attach
+ *
+ * Description:
+ *   Configure the USART to operation in interrupt driven mode.  This method is
+ *   called when the serial port is opened.  Normally, this is just after the
+ *   the setup() method is called, however, the serial console may operate in
+ *   a non-interrupt driven mode during the boot phase.
+ *
+ *   RX and TX interrupts are not enabled when by the attach method (unless the
+ *   hardware supports multiple levels of interrupt enabling).  The RX and TX
+ *   interrupts are not enabled until the txint() and rxint() methods are called.
+ *
+ ****************************************************************************/
+
+static int up_attach(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  /* Attach the IRQ */
+
+  return irq_attach(priv->irq, up_interrupt);
+}
+
+/****************************************************************************
+ * Name: up_detach
+ *
+ * Description:
+ *   Detach USART interrupts.  This method is called when the serial port is
+ *   closed normally just before the shutdown method is called.  The exception
+ *   is the serial console which is never shutdown.
+ *
+ ****************************************************************************/
+
+static void up_detach(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+# warning "Missing logic"
+  irq_detach(priv->irq);
+}
+
+/****************************************************************************
+ * Name: up_interrupt
+ *
+ * Description:
+ *   This is the USART interrupt handler.  It will be invoked when an
+ *   interrupt received on the 'irq'  It should call uart_transmitchars or
+ *   uart_receivechar to perform the appropriate data transfers.  The
+ *   interrupt handling logic must be able to map the 'irq' number into the
+ *   approprite uart_dev_s structure in order to call these functions.
+ *
+ ****************************************************************************/
+
+static int up_interrupt(int irq, void *context)
+{
+  struct uart_dev_s *dev = NULL;
+  struct up_dev_s   *priv;
+  uint32_t           csr;
+  int                passes;
+  bool               handled;
+
+#ifdef CONFIG_AVR_USART1_RS232
+  if (g_usart1priv.irq == irq)
+    {
+      dev = &g_usart1port;
+    }
+  else
+#endif
+    {
+      PANIC(OSERR_INTERNAL);
+    }
+  priv = (struct up_dev_s*)dev->priv;
+  DEBUGASSERT(priv);
+
+  /* Loop until there are no characters to be transferred or,
+   * until we have been looping for a long time.
+   */
+
+  handled = true;
+  for (passes = 0; passes < 256 && handled; passes++)
+    {
+      handled = false;
+
+# warning "Missing logic"
+      /* Handle incoming, receive bytes (with or without timeout) */
+
+# warning "Missing logic"
+        {
+           /* Received data ready... process incoming bytes */
+
+           uart_recvchars(dev);
+           handled = true;
+        }
+
+      /* Handle outgoing, transmit bytes */
+
+# warning "Missing logic"
+        {
+           /* Transmit data regiser empty ... process outgoing bytes */
+
+           uart_xmitchars(dev);
+           handled = true;
+        }
+    }
+    return OK;
+}
+
+/****************************************************************************
+ * Name: up_ioctl
+ *
+ * Description:
+ *   All ioctl calls will be routed through this method
+ *
+ ****************************************************************************/
+
+static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
+{
+#if 0 /* Reserved for future growth */
+  struct inode      *inode;
+  struct uart_dev_s *dev;
+  struct up_dev_s   *priv;
+  int                ret = OK;
+
+  DEBUGASSERT(filep, filep->f_inode);
+  inode = filep->f_inode;
+  dev   = inode->i_private;
+
+  DEBUGASSERT(dev, dev->priv)
+  priv = (struct up_dev_s*)dev->priv;
+
+  switch (cmd)
+    {
+    case xxx: /* Add commands here */
+      break;
+
+    default:
+      ret = -ENOTTY;
+      break;
+    }
+
+  return ret;
+#else
+  return -ENOTTY;
+#endif
+}
+
+/****************************************************************************
+ * Name: up_receive
+ *
+ * Description:
+ *   Called (usually) from the interrupt level to receive one
+ *   character from the USART.  Error bits associated with the
+ *   receipt are provided in the return 'status'.
+ *
+ ****************************************************************************/
+
+static int up_receive(struct uart_dev_s *dev, uint32_t *status)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  /* Get the Rx byte.  The USART Rx interrupt flag is cleared by side effect
+   * when reading the received character.
+   */
+
+# warning "Missing logic"
+
+  /* Return status information */
+
+  if (status)
+    {
+# warning "Missing logic"
+    }
+
+  /* Then return the actual received byte */
+
+# warning "Missing logic"
+  return 0;
+}
+
+/****************************************************************************
+ * Name: up_rxint
+ *
+ * Description:
+ *   Call to enable or disable RX interrupts
+ *
+ ****************************************************************************/
+
+static void up_rxint(struct uart_dev_s *dev, bool enable)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  if (enable)
+    {
+      /* Receive an interrupt when their is anything in the Rx data register (or an Rx
+       * timeout occurs).
+       */
+
+#ifndef CONFIG_SUPPRESS_SERIAL_INTS
+# warning "Missing logic"
+#endif
+    }
+  else
+    {
+# warning "Missing logic"
+    }
+}
+
+/****************************************************************************
+ * Name: up_rxavailable
+ *
+ * Description:
+ *   Return true if the receive register is not empty
+ *
+ ****************************************************************************/
+
+static bool up_rxavailable(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+# warning "Missing logic"
+  return 0;
+}
+
+/****************************************************************************
+ * Name: up_send
+ *
+ * Description:
+ *   This method will send one byte on the USART.
+ *
+ ****************************************************************************/
+
+static void up_send(struct uart_dev_s *dev, int ch)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+# warning "Missing logic"
+  return 0;
+}
+
+/****************************************************************************
+ * Name: up_txint
+ *
+ * Description:
+ *   Call to enable or disable TX interrupts
+ *
+ ****************************************************************************/
+
+static void up_txint(struct uart_dev_s *dev, bool enable)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+  irqstate_t flags;
+
+  flags = irqsave();
+  if (enable)
+    {
+      /* Set to receive an interrupt when the TX data register is empty */
+
+#ifndef CONFIG_SUPPRESS_SERIAL_INTS
+# warning "Missing logic"
+
+      /* Fake a TX interrupt here by just calling uart_xmitchars() with
+       * interrupts disabled (note this may recurse).
+       */
+
+      uart_xmitchars(dev);
+#endif
+    }
+  else
+    {
+      /* Disable the TX interrupt */
+
+# warning "Missing logic"
+    }
+  irqrestore(flags);
+}
+
+/****************************************************************************
+ * Name: up_txready
+ *
+ * Description:
+ *   Return true if the tranmsit data register is empty
+ *
+ ****************************************************************************/
+
+static bool up_txready(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+# warning "Missing logic"
+  return 0;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_earlyserialinit
+ *
+ * Description:
+ *   Performs the low level USART initialization early in debug so that the
+ *   serial console will be available during bootup.  This must be called
+ *   before up_serialinit.  NOTE:  This function depends on GPIO pin
+ *   configuration performed in up_consoleinit() and main clock iniialization
+ *   performed in up_clkinitialize().
+ *
+ ****************************************************************************/
+
+void up_earlyserialinit(void)
+{
+  /* Disable all USARTS */
+
+  up_disableusartint(TTYS0_DEV.priv, NULL);
+#ifdef TTYS1_DEV
+  up_disableusartint(TTYS1_DEV.priv, NULL);
+#endif
+
+  /* Configuration whichever one is the console */
+
+#ifdef HAVE_SERIAL_CONSOLE
+  CONSOLE_DEV.isconsole = true;
+  up_setup(&CONSOLE_DEV);
+#endif
+}
+
+/****************************************************************************
+ * Name: up_serialinit
+ *
+ * Description:
+ *   Register serial console and serial ports.  This assumes
+ *   that up_earlyserialinit was called previously.
+ *
+ ****************************************************************************/
+
+void up_serialinit(void)
+{
+  /* Register the console */
+
+#ifdef HAVE_SERIAL_CONSOLE
+  (void)uart_register("/dev/console", &CONSOLE_DEV);
+#endif
+
+  /* Register all USARTs */
+
+  (void)uart_register("/dev/ttyS0", &TTYS0_DEV);
+#ifdef TTYS1_DEV
+  (void)uart_register("/dev/ttyS1", &TTYS1_DEV);
+#endif
+}
+
+/****************************************************************************
+ * Name: up_putc
+ *
+ * Description:
+ *   Provide priority, low-level access to support OS debug  writes
+ *
+ ****************************************************************************/
+
+int up_putc(int ch)
+{
+#ifdef HAVE_SERIAL_CONSOLE
+  struct up_dev_s *priv = (struct up_dev_s*)CONSOLE_DEV.priv;
+  uint32_t imr;
+
+  up_disableusartint(priv, &imr);
+
+  /* Check for LF */
+
+  if (ch == '\n')
+    {
+      /* Add CR */
+
+      up_lowputc('\r');
+    }
+
+  up_lowputc(ch);
+  up_restoreusartint(priv, imr);
+#endif
+  return ch;
+}
+
+#else /* CONFIG_USE_SERIALDRIVER */
+
+/****************************************************************************
+ * Name: up_putc
+ *
+ * Description:
+ *   Provide priority, low-level access to support OS debug writes
+ *
+ ****************************************************************************/
+
+int up_putc(int ch)
+{
+#ifdef HAVE_SERIAL_CONSOLE
+  /* Check for LF */
+
+  if (ch == '\n')
+    {
+      /* Add CR */
+
+      up_lowputc('\r');
+    }
+
+  up_lowputc(ch);
+#endif
+  return ch;
+}
+
+#endif /* CONFIG_USE_SERIALDRIVER */
+
diff --git a/nuttx/arch/avr/src/at90usb/at90usb_timerisr.c b/nuttx/arch/avr/src/at90usb/at90usb_timerisr.c
new file mode 100644
index 000000000..079433b8d
--- /dev/null
+++ b/nuttx/arch/avr/src/at90usb/at90usb_timerisr.c
@@ -0,0 +1,165 @@
+/****************************************************************************
+ * arch/avr/src/at90usb/at90usb_timerisr.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 <time.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+#include <arch/board/board.h>
+#include <avr/io.h>
+
+#include "up_arch.h"
+
+#include "at90usb_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/* The CPU frequency is given by BOARD_CPU_CLOCK (defined in board.h).  The
+ * desired interrupt frequency is given by CONFIG_MSEC_PER_TICK.  An unscaled
+ * ideal match is given by:
+ *
+ *   CLOCK = CPU_CLOCK / DIVISOR                      # CPU clocks/sec
+ *   MATCH = CLOCK / CLOCKS_PER_SEC                   # CPU clocks/timer tick
+ *   MATCH = CPU_CLOCK / DIVISOR / CLOCKS_PER_SEC     # CPU clocks/timer tick
+ *
+ * But we only have 16-bits of accuracy so we need to pick the smallest
+ * divisor using the following brute force calculation:
+ */
+
+#define MATCH1      (( BOARD_CPU_CLOCK                + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+#define MATCH8     ((((BOARD_CPU_CLOCK + 4) / 8)      + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+#define MATCH64    ((((BOARD_CPU_CLOCK + 8) / 64)     + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+#define MATCH256   ((((BOARD_CPU_CLOCK + 128) / 256)  + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+#define MATCH1024  ((((BOARD_CPU_CLOCK + 512) / 1024) + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+
+#if MATCH1 <= 65536
+#  define MATCH   (MATCH1-1)
+#  define PRESCALE 1
+#elif MATCH8 <= 65536
+#  define MATCH    (MATCH8-1)
+#  define PRESCALE 2
+#elif MATCH64 <= 65536
+#  define MATCH    (MATCH64-1)
+#  define PRESCALE 3
+#elif MATCH256 <= 65536
+#  define MATCH    (MATCH256-1)
+#  define PRESCALE 4
+#elif MATCH1024 <= 65536
+#  define MATCH    (MATCH1024-1)
+#  define PRESCALE 5
+#else
+#  error "Cannot represent this timer frequency"
+#endif
+
+/*
+ * Eg. CPU_CLOCK = 8MHz, CLOCKS_PER_SEC = 100
+ *
+ *   MATCH1      ((8000000 + 50) / 100) = 80,000  FREQ=100.0Hz
+ *   MATCH8      ((1000000 + 50) / 100) = 10,000  FREQ=100.0Hz <-- this one
+ *   MATCH64     (( 125000 + 50) / 100) =  1,250  FREQ=100.0Hz
+ *   MATCH256    ((  31250 + 50) / 100) =    313  FREQ=99.8Hz
+ *   MATCH1024   ((   7804 + 50) / 100) =     78  FREQ=100.1Hz
+ */
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  up_timerisr
+ *
+ * Description:
+ *   The timer ISR will perform a variety of services for various portions
+ *   of the systems.
+ *
+ ****************************************************************************/
+
+int up_timerisr(int irq, uint32_t *regs)
+{
+   /* Process timer interrupt */
+
+   sched_process_timer();
+   return 0;
+}
+
+/****************************************************************************
+ * Function:  up_timerinit
+ *
+ * Description:
+ *   This function is called during start-up to initialize the timer
+ *   interrupt.  NOTE:  This function depends on setup of OSC32 by
+ *   up_clkinitialize().
+ *
+ ****************************************************************************/
+
+void up_timerinit(void)
+{
+  /* Setup timer 1 compare match A to generate a tick interrupt.
+   *
+   * First, setup the match value for compare match A.
+   */
+
+  OCR1AH = (uint8_t)((uint16_t)MATCH >> 8);
+  OCR1AL = (uint8_t)((uint16_t)MATCH & 0xff);
+
+  /* Setup clock source and compare match behaviour. */
+
+  TCCR1A = 0x08 | PRESCALE;
+
+  /* Attach the timer interrupt vector */
+
+  (void)irq_attach(AT90USB_IRQ_T2COMPA, (xcpt_t)up_timerisr);
+
+  /* Enable the interrupt on compare match A */
+
+  TIMSK1 |= 0x10;
+}
diff --git a/nuttx/arch/avr/src/atmega/Make.defs b/nuttx/arch/avr/src/atmega/Make.defs
index 9bcf64ea0..a761b4938 100644
--- a/nuttx/arch/avr/src/atmega/Make.defs
+++ b/nuttx/arch/avr/src/atmega/Make.defs
@@ -42,10 +42,11 @@ HEAD_ASRC	= atmega_head.S
 CMN_ASRCS	= up_switchcontext.S
 CMN_CSRCS	= up_allocateheap.c up_assert.c up_blocktask.c up_copystate.c \
 			  up_createstack.c up_doirq.c up_exit.c  up_idle.c up_initialize.c \
-			  up_interruptcontext.c up_lowputs.c up_mdelay.c up_modifyreg8.c \
-			  up_modifyreg16.c up_modifyreg32.c up_puts.c up_releasepending.c \
-			  up_releasestack.c up_reprioritizertr.c up_schedulesigaction.c \
-			  up_sigdeliver.c up_udelay.c up_unblocktask.c up_usestack.c
+			  up_initialstate.c up_interruptcontext.c up_irq.c up_lowputs.c \
+			  up_mdelay.c up_modifyreg8.c up_modifyreg16.c up_modifyreg32.c \
+			  up_puts.c up_releasepending.c up_releasestack.c \
+			  up_reprioritizertr.c up_schedulesigaction.c up_sigdeliver.c \
+			  up_udelay.c up_unblocktask.c up_usestack.c
 
 # Configuration-dependent common files
 
@@ -56,7 +57,7 @@ endif
 # Required ATMEGA files
 
 CHIP_ASRCS	= atmega_exceptions.S
-CHIP_CSRCS	= 
+CHIP_CSRCS	= atmega_lowconsole.c atmega_lowinit.c atmega_serial.c atmega_timerisr.c
 
 # Configuration-dependent ATMEGA files
 
diff --git a/nuttx/arch/avr/src/atmega/atmega_config.h b/nuttx/arch/avr/src/atmega/atmega_config.h
index 09b1c11d9..2cb483160 100644
--- a/nuttx/arch/avr/src/atmega/atmega_config.h
+++ b/nuttx/arch/avr/src/atmega/atmega_config.h
@@ -45,6 +45,28 @@
 /************************************************************************************
  * Pre-processor Definitions
  ************************************************************************************/
+/* USARTs ***************************************************************************/
+
+#undef HAVE_USART_DEVICE
+#if defined(CONFIG_AVR_USART0) || defined(CONFIG_AVR_USART0)
+#  define HAVE_USART_DEVICE 1
+#endif
+
+/* Is there a serial console?  There should be at most one defined.  It
+ * could be on any USARTn, n=0,1
+ */
+
+#if defined(CONFIG_USART0_SERIAL_CONSOLE) && defined(CONFIG_AVR_USART0)
+#  undef CONFIG_USART1_SERIAL_CONSOLE
+#  define HAVE_SERIAL_CONSOLE 1
+#elif defined(CONFIG_USART1_SERIAL_CONSOLE) && defined(CONFIG_AVR_USART1)
+#  undef CONFIG_USART0_SERIAL_CONSOLE
+#  define HAVE_SERIAL_CONSOLE 1
+#else
+#  undef CONFIG_USART0_SERIAL_CONSOLE
+#  undef CONFIG_USART1_SERIAL_CONSOLE
+#  undef HAVE_SERIAL_CONSOLE
+#endif
 
 /************************************************************************************
  * Public Types
diff --git a/nuttx/arch/avr/src/atmega/atmega_head.S b/nuttx/arch/avr/src/atmega/atmega_head.S
index 2ebd8ecec..281b1e159 100755
--- a/nuttx/arch/avr/src/atmega/atmega_head.S
+++ b/nuttx/arch/avr/src/atmega/atmega_head.S
@@ -66,6 +66,7 @@
  ****************************************************************************/

 

 	.file	"up_nommuhead.S"

+	.global	__start			/* Entry point */

 	.global	_sbss			/* Start of .bss.  Defined by ld.script */

 	.global	_ebss			/* End of .bss.  Defined by ld.script */

 	.global	_sdata			/* Start of .data section in RAM */

@@ -242,9 +243,13 @@ __do_clear_bss:
 	cpc		r27, r17

 	brne	.Lclearloop

 

+	/* Perform any low-level initialization */

+

+	call	up_lowinit

+

 	/* Now start NuttX */

 

-	call	os_start		/* Start NuttX */

+	call	os_start

 	jmp		exit

 	.endfunc

 

diff --git a/nuttx/arch/avr/src/atmega/atmega_lowconsole.c b/nuttx/arch/avr/src/atmega/atmega_lowconsole.c
new file mode 100644
index 000000000..a7ed60c9b
--- /dev/null
+++ b/nuttx/arch/avr/src/atmega/atmega_lowconsole.c
@@ -0,0 +1,174 @@
+/******************************************************************************
+ * arch/avr/src/atmega/atmega_lowconsole.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 "atmega_config.h"
+
+#include <assert.h>
+#include <debug.h>
+
+#include <arch/irq.h>
+#include <arch/board/board.h>
+
+#include "up_arch.h"
+#include "up_internal.h"
+#include "atmega_internal.h"
+
+/******************************************************************************
+ * Private Definitions
+ ******************************************************************************/
+
+/* Select USART parameters for the selected console */
+
+#if defined(CONFIG_USART0_SERIAL_CONSOLE)
+#  define AVR__CONSOLE_BASE     AVR__USART0_BASE
+#  define AVR__CONSOLE_BAUD     CONFIG_USART0_BAUD
+#  define AVR__CONSOLE_BITS     CONFIG_USART0_BITS
+#  define AVR__CONSOLE_PARITY   CONFIG_USART0_PARITY
+#  define AVR__CONSOLE_2STOP    CONFIG_USART0_2STOP
+#elif defined(CONFIG_USART1_SERIAL_CONSOLE)
+#  define AVR__CONSOLE_BASE     AVR__USART1_BASE
+#  define AVR__CONSOLE_BAUD     CONFIG_USART1_BAUD
+#  define AVR__CONSOLE_BITS     CONFIG_USART1_BITS
+#  define AVR__CONSOLE_PARITY   CONFIG_USART1_PARITY
+#  define AVR__CONSOLE_2STOP    CONFIG_USART1_2STOP
+#else
+#  error "No CONFIG_USARTn_SERIAL_CONSOLE Setting"
+#endif
+
+/******************************************************************************
+ * Private Types
+ ******************************************************************************/
+
+/******************************************************************************
+ * Private Function Prototypes
+ ******************************************************************************/
+
+/******************************************************************************
+ * Global Variables
+ ******************************************************************************/
+
+/******************************************************************************
+ * Private Variables
+ ******************************************************************************/
+
+/******************************************************************************
+ * Private Functions
+ ******************************************************************************/
+
+/******************************************************************************
+ * Name: usart_setbaudrate
+ *
+ * Description:
+ *   Configure the USART baud rate.
+ *
+ ******************************************************************************/
+
+#ifdef HAVE_USART_DEVICE
+static void usart_setbaudrate(uintptr_t usart_base, uint32_t baudrate)
+{
+# warning "Missing logic"
+}
+#endif
+
+/******************************************************************************
+ * Public Functions
+ ******************************************************************************/
+
+/******************************************************************************
+ * Name: usart_reset
+ *
+ * Description:
+ *   Reset a USART.
+ *
+ ******************************************************************************/
+
+#ifdef HAVE_USART_DEVICE
+void usart_reset(uintptr_t usart_base)
+{
+# warning "Missing logic"
+}
+#endif
+
+/******************************************************************************
+ * Name: usart_configure
+ *
+ * Description:
+ *   Configure a USART as a RS-232 USART.
+ *
+ ******************************************************************************/
+
+#ifdef HAVE_USART_DEVICE
+void usart_configure(uintptr_t usart_base, uint32_t baud, unsigned int parity,
+                     unsigned int nbits, bool stop2)
+{
+# warning "Missing logic"
+}
+#endif
+
+/******************************************************************************
+ * Name: up_consoleinit
+ *
+ * Description:
+ *   Initialize a console for debug output.  This function is called very
+ *   early in the intialization sequence to configure the serial console uart
+ *   (only).
+ *
+ ******************************************************************************/
+
+void up_consoleinit(void)
+{
+# warning "Missing logic"
+}
+
+/******************************************************************************
+ * Name: up_lowputc
+ *
+ * Description:
+ *   Output one byte on the serial console
+ *
+ ******************************************************************************/
+
+void up_lowputc(char ch)
+{
+#ifdef HAVE_SERIAL_CONSOLE
+# warning "Missing logic"
+#endif
+}
+
diff --git a/nuttx/arch/avr/src/atmega/atmega_lowinit.c b/nuttx/arch/avr/src/atmega/atmega_lowinit.c
new file mode 100644
index 000000000..9361e26b0
--- /dev/null
+++ b/nuttx/arch/avr/src/atmega/atmega_lowinit.c
@@ -0,0 +1,103 @@
+/**************************************************************************
+ * arch/avr/src/atmega/atmega_lowinit.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 "atmega_config.h"
+#include "up_internal.h"
+#include "atmega_internal.h"
+
+/**************************************************************************
+ * Private Definitions
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Types
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Function Prototypes
+ **************************************************************************/
+
+/**************************************************************************
+ * Global Variables
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Variables
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Functions
+ **************************************************************************/
+
+/**************************************************************************
+ * Public Functions
+ **************************************************************************/
+
+/**************************************************************************
+ * Name: up_lowinit
+ *
+ * Description:
+ *   This performs basic initialization of the USART used for the serial
+ *   console.  Its purpose is to get the console output availabe as soon
+ *   as possible.
+ *
+ **************************************************************************/
+
+void up_lowinit(void)
+{
+  /* Initialize a console (probably a serial console) */
+
+  up_consoleinit();
+
+  /* Perform early serial initialization (so that we will have debug output
+   * available as soon as possible).
+   */
+
+#ifdef CONFIG_USE_EARLYSERIALINIT
+  up_earlyserialinit();
+#endif
+
+  /* Perform board-level initialization */
+
+  up_boardinitialize();
+}
+
+
diff --git a/nuttx/arch/avr/src/atmega/atmega_serial.c b/nuttx/arch/avr/src/atmega/atmega_serial.c
new file mode 100644
index 000000000..7b5e02bd9
--- /dev/null
+++ b/nuttx/arch/avr/src/atmega/atmega_serial.c
@@ -0,0 +1,718 @@
+/****************************************************************************
+ * arch/avr/src/atmega/atmega_serial.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 "atmega_config.h"
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <semaphore.h>
+#include <string.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/irq.h>
+#include <nuttx/arch.h>
+#include <nuttx/serial.h>
+
+#include <arch/board/board.h>
+
+#include "up_arch.h"
+#include "up_internal.h"
+#include "os_internal.h"
+#include "atmega_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/* Some sanity checks *******************************************************/
+
+/* Is there at least one USART enabled and configured as a RS-232 device? */
+
+#ifndef HAVE_USART_DEVICE
+#  warning "No USARTs enabled as RS-232 devices"
+#endif
+
+/* If we are not using the serial driver for the console, then we still must
+ * provide some minimal implementation of up_putc.
+ */
+
+#ifdef CONFIG_USE_SERIALDRIVER
+
+/* Which USART with be tty0/console and which tty1? */
+
+#if defined(CONFIG_USART0_SERIAL_CONSOLE)
+#  define CONSOLE_DEV     g_usart0port     /* USART0 is console */
+#  define TTYS0_DEV       g_usart0port     /* USART0 is ttyS0 */
+#  ifdef CONFIG_AVR_USART1_RS232
+#    define TTYS1_DEV     g_usart1port     /* USART1 is ttyS1 */
+#  else
+#    undef TTYS1_DEV                       /* No ttyS1 */
+#  endif
+#elif defined(CONFIG_USART1_SERIAL_CONSOLE)
+#  define CONSOLE_DEV     g_usart1port     /* USART1 is console */
+#  define TTYS0_DEV       g_usart1port     /* USART1 is ttyS0 */
+#  ifdef CONFIG_AVR_USART0_RS232
+#    define TTYS1_DEV     g_usart0port     /* USART0 is ttyS1 */
+#  else
+#    undef TTYS1_DEV                       /* No ttyS1 */
+#  endif
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct up_dev_s
+{
+  uintptr_t usartbase; /* Base address of USART registers */
+  uint32_t  baud;      /* Configured baud */
+  uint32_t  csr;       /* Saved channel status register contents */
+  uint8_t   irq;       /* IRQ associated with this USART */
+  uint8_t   parity;    /* 0=none, 1=odd, 2=even */
+  uint8_t   bits;      /* Number of bits (5, 6, 7 or 8) */
+  bool      stopbits2; /* true: Configure with 2 stop bits instead of 1 */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int  up_setup(struct uart_dev_s *dev);
+static void up_shutdown(struct uart_dev_s *dev);
+static int  up_attach(struct uart_dev_s *dev);
+static void up_detach(struct uart_dev_s *dev);
+static int  up_interrupt(int irq, void *context);
+static int  up_ioctl(struct file *filep, int cmd, unsigned long arg);
+static int  up_receive(struct uart_dev_s *dev, uint32_t *status);
+static void up_rxint(struct uart_dev_s *dev, bool enable);
+static bool up_rxavailable(struct uart_dev_s *dev);
+static void up_send(struct uart_dev_s *dev, int ch);
+static void up_txint(struct uart_dev_s *dev, bool enable);
+static bool up_txready(struct uart_dev_s *dev);
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+struct uart_ops_s g_uart_ops =
+{
+  .setup          = up_setup,
+  .shutdown       = up_shutdown,
+  .attach         = up_attach,
+  .detach         = up_detach,
+  .ioctl          = up_ioctl,
+  .receive        = up_receive,
+  .rxint          = up_rxint,
+  .rxavailable    = up_rxavailable,
+  .send           = up_send,
+  .txint          = up_txint,
+  .txready        = up_txready,
+  .txempty        = up_txready,
+};
+
+/* I/O buffers */
+
+#ifdef CONFIG_AVR_USART0_RS232
+static char g_usart0rxbuffer[CONFIG_USART0_RXBUFSIZE];
+static char g_usart0txbuffer[CONFIG_USART0_TXBUFSIZE];
+#endif
+#ifdef CONFIG_AVR_USART1_RS232
+static char g_usart1rxbuffer[CONFIG_USART1_RXBUFSIZE];
+static char g_usart1txbuffer[CONFIG_USART1_TXBUFSIZE];
+#endif
+
+/* This describes the state of the AVR32 USART0 ports. */
+
+#ifdef CONFIG_AVR_USART0_RS232
+static struct up_dev_s g_usart0priv =
+{
+  .usartbase      = AVR_USART0_BASE,
+  .baud           = CONFIG_USART0_BAUD,
+  .irq            = AVR_IRQ_USART0,
+  .parity         = CONFIG_USART0_PARITY,
+  .bits           = CONFIG_USART0_BITS,
+  .stopbits2      = CONFIG_USART0_2STOP,
+};
+
+static uart_dev_t g_usart0port =
+{
+  .recv     =
+  {
+    .size   = CONFIG_USART0_RXBUFSIZE,
+    .buffer = g_usart0rxbuffer,
+  },
+  .xmit     =
+  {
+    .size   = CONFIG_USART0_TXBUFSIZE,
+    .buffer = g_usart0txbuffer,
+  },
+  .ops      = &g_uart_ops,
+  .priv     = &g_usart0priv,
+};
+#endif
+
+/* This describes the state of the AVR32 USART1 port. */
+
+#ifdef CONFIG_AVR_USART1_RS232
+static struct up_dev_s g_usart1priv =
+{
+  .usartbase      = AVR_USART1_BASE,
+  .baud           = CONFIG_USART1_BAUD,
+  .irq            = AVR_IRQ_USART1,
+  .parity         = CONFIG_USART1_PARITY,
+  .bits           = CONFIG_USART1_BITS,
+  .stopbits2      = CONFIG_USART1_2STOP,
+};
+
+static uart_dev_t g_usart1port =
+{
+  .recv     =
+  {
+    .size   = CONFIG_USART1_RXBUFSIZE,
+    .buffer = g_usart1rxbuffer,
+  },
+  .xmit     =
+  {
+    .size   = CONFIG_USART1_TXBUFSIZE,
+    .buffer = g_usart1txbuffer,
+   },
+  .ops      = &g_uart_ops,
+  .priv     = &g_usart1priv,
+};
+#endif
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_serialin
+ ****************************************************************************/
+
+static inline uint32_t up_serialin(struct up_dev_s *priv, int offset)
+{
+# warning "Missing logic"
+}
+
+/****************************************************************************
+ * Name: up_serialout
+ ****************************************************************************/
+
+static inline void up_serialout(struct up_dev_s *priv, int offset, uint32_t value)
+{
+# warning "Missing logic"
+}
+
+/****************************************************************************
+ * Name: up_restoreusartint
+ ****************************************************************************/
+
+static void up_restoreusartint(struct up_dev_s *priv, uint32_t imr)
+{
+# warning "Missing logic"
+}
+
+/****************************************************************************
+ * Name: up_disableusartint
+ ****************************************************************************/
+
+static inline void up_disableusartint(struct up_dev_s *priv, uint32_t *imr)
+{
+# warning "Missing logic"
+}
+
+/****************************************************************************
+ * Name: up_setup
+ *
+ * Description:
+ *   Configure the USART baud, bits, parity, etc. This method is called the
+ *   first time that the serial port is opened.
+ *
+ ****************************************************************************/
+
+static int up_setup(struct uart_dev_s *dev)
+{
+#ifndef CONFIG_SUPPRESS_UART_CONFIG
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  /* Configure the USART as an RS-232 UART */
+
+  usart_configure(priv->usartbase, priv->baud, priv->parity,
+                  priv->bits, priv->stopbits2);
+#endif
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: up_shutdown
+ *
+ * Description:
+ *   Disable the USART.  This method is called when the serial
+ *   port is closed
+ *
+ ****************************************************************************/
+
+static void up_shutdown(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  /* Reset, disable interrupts, and disable Rx and Tx */
+
+  usart_reset(priv->usartbase);
+}
+
+/****************************************************************************
+ * Name: up_attach
+ *
+ * Description:
+ *   Configure the USART to operation in interrupt driven mode.  This method is
+ *   called when the serial port is opened.  Normally, this is just after the
+ *   the setup() method is called, however, the serial console may operate in
+ *   a non-interrupt driven mode during the boot phase.
+ *
+ *   RX and TX interrupts are not enabled when by the attach method (unless the
+ *   hardware supports multiple levels of interrupt enabling).  The RX and TX
+ *   interrupts are not enabled until the txint() and rxint() methods are called.
+ *
+ ****************************************************************************/
+
+static int up_attach(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  /* Attach the IRQ */
+
+  return irq_attach(priv->irq, up_interrupt);
+}
+
+/****************************************************************************
+ * Name: up_detach
+ *
+ * Description:
+ *   Detach USART interrupts.  This method is called when the serial port is
+ *   closed normally just before the shutdown method is called.  The exception
+ *   is the serial console which is never shutdown.
+ *
+ ****************************************************************************/
+
+static void up_detach(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+# warning "Missing logic"
+  irq_detach(priv->irq);
+}
+
+/****************************************************************************
+ * Name: up_interrupt
+ *
+ * Description:
+ *   This is the USART interrupt handler.  It will be invoked when an
+ *   interrupt received on the 'irq'  It should call uart_transmitchars or
+ *   uart_receivechar to perform the appropriate data transfers.  The
+ *   interrupt handling logic must be able to map the 'irq' number into the
+ *   approprite uart_dev_s structure in order to call these functions.
+ *
+ ****************************************************************************/
+
+static int up_interrupt(int irq, void *context)
+{
+  struct uart_dev_s *dev = NULL;
+  struct up_dev_s   *priv;
+  uint32_t           csr;
+  int                passes;
+  bool               handled;
+
+#ifdef CONFIG_AVR_USART0_RS232
+  if (g_usart0priv.irq == irq)
+    {
+      dev = &g_usart0port;
+    }
+  else
+#endif
+#ifdef CONFIG_AVR_USART1_RS232
+  if (g_usart1priv.irq == irq)
+    {
+      dev = &g_usart1port;
+    }
+  else
+#endif
+    {
+      PANIC(OSERR_INTERNAL);
+    }
+  priv = (struct up_dev_s*)dev->priv;
+  DEBUGASSERT(priv);
+
+  /* Loop until there are no characters to be transferred or,
+   * until we have been looping for a long time.
+   */
+
+  handled = true;
+  for (passes = 0; passes < 256 && handled; passes++)
+    {
+      handled = false;
+
+# warning "Missing logic"
+      /* Handle incoming, receive bytes (with or without timeout) */
+
+# warning "Missing logic"
+        {
+           /* Received data ready... process incoming bytes */
+
+           uart_recvchars(dev);
+           handled = true;
+        }
+
+      /* Handle outgoing, transmit bytes */
+
+# warning "Missing logic"
+        {
+           /* Transmit data regiser empty ... process outgoing bytes */
+
+           uart_xmitchars(dev);
+           handled = true;
+        }
+    }
+    return OK;
+}
+
+/****************************************************************************
+ * Name: up_ioctl
+ *
+ * Description:
+ *   All ioctl calls will be routed through this method
+ *
+ ****************************************************************************/
+
+static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
+{
+#if 0 /* Reserved for future growth */
+  struct inode      *inode;
+  struct uart_dev_s *dev;
+  struct up_dev_s   *priv;
+  int                ret = OK;
+
+  DEBUGASSERT(filep, filep->f_inode);
+  inode = filep->f_inode;
+  dev   = inode->i_private;
+
+  DEBUGASSERT(dev, dev->priv)
+  priv = (struct up_dev_s*)dev->priv;
+
+  switch (cmd)
+    {
+    case xxx: /* Add commands here */
+      break;
+
+    default:
+      ret = -ENOTTY;
+      break;
+    }
+
+  return ret;
+#else
+  return -ENOTTY;
+#endif
+}
+
+/****************************************************************************
+ * Name: up_receive
+ *
+ * Description:
+ *   Called (usually) from the interrupt level to receive one
+ *   character from the USART.  Error bits associated with the
+ *   receipt are provided in the return 'status'.
+ *
+ ****************************************************************************/
+
+static int up_receive(struct uart_dev_s *dev, uint32_t *status)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  /* Get the Rx byte.  The USART Rx interrupt flag is cleared by side effect
+   * when reading the received character.
+   */
+
+# warning "Missing logic"
+
+  /* Return status information */
+
+  if (status)
+    {
+# warning "Missing logic"
+    }
+
+  /* Then return the actual received byte */
+
+# warning "Missing logic"
+  return 0;
+}
+
+/****************************************************************************
+ * Name: up_rxint
+ *
+ * Description:
+ *   Call to enable or disable RX interrupts
+ *
+ ****************************************************************************/
+
+static void up_rxint(struct uart_dev_s *dev, bool enable)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+
+  if (enable)
+    {
+      /* Receive an interrupt when their is anything in the Rx data register (or an Rx
+       * timeout occurs).
+       */
+
+#ifndef CONFIG_SUPPRESS_SERIAL_INTS
+# warning "Missing logic"
+#endif
+    }
+  else
+    {
+# warning "Missing logic"
+    }
+}
+
+/****************************************************************************
+ * Name: up_rxavailable
+ *
+ * Description:
+ *   Return true if the receive register is not empty
+ *
+ ****************************************************************************/
+
+static bool up_rxavailable(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+# warning "Missing logic"
+  return 0;
+}
+
+/****************************************************************************
+ * Name: up_send
+ *
+ * Description:
+ *   This method will send one byte on the USART.
+ *
+ ****************************************************************************/
+
+static void up_send(struct uart_dev_s *dev, int ch)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+# warning "Missing logic"
+  return 0;
+}
+
+/****************************************************************************
+ * Name: up_txint
+ *
+ * Description:
+ *   Call to enable or disable TX interrupts
+ *
+ ****************************************************************************/
+
+static void up_txint(struct uart_dev_s *dev, bool enable)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+  irqstate_t flags;
+
+  flags = irqsave();
+  if (enable)
+    {
+      /* Set to receive an interrupt when the TX data register is empty */
+
+#ifndef CONFIG_SUPPRESS_SERIAL_INTS
+# warning "Missing logic"
+
+      /* Fake a TX interrupt here by just calling uart_xmitchars() with
+       * interrupts disabled (note this may recurse).
+       */
+
+      uart_xmitchars(dev);
+#endif
+    }
+  else
+    {
+      /* Disable the TX interrupt */
+
+# warning "Missing logic"
+    }
+  irqrestore(flags);
+}
+
+/****************************************************************************
+ * Name: up_txready
+ *
+ * Description:
+ *   Return true if the tranmsit data register is empty
+ *
+ ****************************************************************************/
+
+static bool up_txready(struct uart_dev_s *dev)
+{
+  struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
+# warning "Missing logic"
+  return 0;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_earlyserialinit
+ *
+ * Description:
+ *   Performs the low level USART initialization early in debug so that the
+ *   serial console will be available during bootup.  This must be called
+ *   before up_serialinit.  NOTE:  This function depends on GPIO pin
+ *   configuration performed in up_consoleinit() and main clock iniialization
+ *   performed in up_clkinitialize().
+ *
+ ****************************************************************************/
+
+void up_earlyserialinit(void)
+{
+  /* Disable all USARTS */
+
+  up_disableusartint(TTYS0_DEV.priv, NULL);
+#ifdef TTYS1_DEV
+  up_disableusartint(TTYS1_DEV.priv, NULL);
+#endif
+
+  /* Configuration whichever one is the console */
+
+#ifdef HAVE_SERIAL_CONSOLE
+  CONSOLE_DEV.isconsole = true;
+  up_setup(&CONSOLE_DEV);
+#endif
+}
+
+/****************************************************************************
+ * Name: up_serialinit
+ *
+ * Description:
+ *   Register serial console and serial ports.  This assumes
+ *   that up_earlyserialinit was called previously.
+ *
+ ****************************************************************************/
+
+void up_serialinit(void)
+{
+  /* Register the console */
+
+#ifdef HAVE_SERIAL_CONSOLE
+  (void)uart_register("/dev/console", &CONSOLE_DEV);
+#endif
+
+  /* Register all USARTs */
+
+  (void)uart_register("/dev/ttyS0", &TTYS0_DEV);
+#ifdef TTYS1_DEV
+  (void)uart_register("/dev/ttyS1", &TTYS1_DEV);
+#endif
+}
+
+/****************************************************************************
+ * Name: up_putc
+ *
+ * Description:
+ *   Provide priority, low-level access to support OS debug  writes
+ *
+ ****************************************************************************/
+
+int up_putc(int ch)
+{
+#ifdef HAVE_SERIAL_CONSOLE
+  struct up_dev_s *priv = (struct up_dev_s*)CONSOLE_DEV.priv;
+  uint32_t imr;
+
+  up_disableusartint(priv, &imr);
+
+  /* Check for LF */
+
+  if (ch == '\n')
+    {
+      /* Add CR */
+
+      up_lowputc('\r');
+    }
+
+  up_lowputc(ch);
+  up_restoreusartint(priv, imr);
+#endif
+  return ch;
+}
+
+#else /* CONFIG_USE_SERIALDRIVER */
+
+/****************************************************************************
+ * Name: up_putc
+ *
+ * Description:
+ *   Provide priority, low-level access to support OS debug writes
+ *
+ ****************************************************************************/
+
+int up_putc(int ch)
+{
+#ifdef HAVE_SERIAL_CONSOLE
+  /* Check for LF */
+
+  if (ch == '\n')
+    {
+      /* Add CR */
+
+      up_lowputc('\r');
+    }
+
+  up_lowputc(ch);
+#endif
+  return ch;
+}
+
+#endif /* CONFIG_USE_SERIALDRIVER */
+
diff --git a/nuttx/arch/avr/src/atmega/atmega_timerisr.c b/nuttx/arch/avr/src/atmega/atmega_timerisr.c
new file mode 100644
index 000000000..6cd11e393
--- /dev/null
+++ b/nuttx/arch/avr/src/atmega/atmega_timerisr.c
@@ -0,0 +1,165 @@
+/****************************************************************************
+ * arch/avr/src/atmega/atmega_timerisr.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 <time.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+#include <arch/board/board.h>
+#include <avr/io.h>
+
+#include "up_arch.h"
+
+#include "atmega_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/* The CPU frequency is given by BOARD_CPU_CLOCK (defined in board.h).  The
+ * desired interrupt frequency is given by CONFIG_MSEC_PER_TICK.  An unscaled
+ * ideal match is given by:
+ *
+ *   CLOCK = CPU_CLOCK / DIVISOR                      # CPU clocks/sec
+ *   MATCH = CLOCK / CLOCKS_PER_SEC                   # CPU clocks/timer tick
+ *   MATCH = CPU_CLOCK / DIVISOR / CLOCKS_PER_SEC     # CPU clocks/timer tick
+ *
+ * But we only have 16-bits of accuracy so we need to pick the smallest
+ * divisor using the following brute force calculation:
+ */
+
+#define MATCH1      (( BOARD_CPU_CLOCK                + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+#define MATCH8     ((((BOARD_CPU_CLOCK + 4) / 8)      + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+#define MATCH64    ((((BOARD_CPU_CLOCK + 8) / 64)     + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+#define MATCH256   ((((BOARD_CPU_CLOCK + 128) / 256)  + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+#define MATCH1024  ((((BOARD_CPU_CLOCK + 512) / 1024) + CLOCKS_PER_SEC/2) / CLOCKS_PER_SEC)
+
+#if MATCH1 <= 65536
+#  define MATCH   (MATCH1-1)
+#  define PRESCALE 1
+#elif MATCH8 <= 65536
+#  define MATCH    (MATCH8-1)
+#  define PRESCALE 2
+#elif MATCH64 <= 65536
+#  define MATCH    (MATCH64-1)
+#  define PRESCALE 3
+#elif MATCH256 <= 65536
+#  define MATCH    (MATCH256-1)
+#  define PRESCALE 4
+#elif MATCH1024 <= 65536
+#  define MATCH    (MATCH1024-1)
+#  define PRESCALE 5
+#else
+#  error "Cannot represent this timer frequency"
+#endif
+
+/*
+ * Eg. CPU_CLOCK = 8MHz, CLOCKS_PER_SEC = 100
+ *
+ *   MATCH1      ((8000000 + 50) / 100) = 80,000  FREQ=100.0Hz
+ *   MATCH8      ((1000000 + 50) / 100) = 10,000  FREQ=100.0Hz <-- this one
+ *   MATCH64     (( 125000 + 50) / 100) =  1,250  FREQ=100.0Hz
+ *   MATCH256    ((  31250 + 50) / 100) =    313  FREQ=99.8Hz
+ *   MATCH1024   ((   7804 + 50) / 100) =     78  FREQ=100.1Hz
+ */
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  up_timerisr
+ *
+ * Description:
+ *   The timer ISR will perform a variety of services for various portions
+ *   of the systems.
+ *
+ ****************************************************************************/
+
+int up_timerisr(int irq, uint32_t *regs)
+{
+   /* Process timer interrupt */
+
+   sched_process_timer();
+   return 0;
+}
+
+/****************************************************************************
+ * Function:  up_timerinit
+ *
+ * Description:
+ *   This function is called during start-up to initialize the timer
+ *   interrupt.  NOTE:  This function depends on setup of OSC32 by
+ *   up_clkinitialize().
+ *
+ ****************************************************************************/
+
+void up_timerinit(void)
+{
+  /* Setup timer 1 compare match A to generate a tick interrupt.
+   *
+   * First, setup the match value for compare match A.
+   */
+
+  OCR1AH = (uint8_t)((uint16_t)MATCH >> 8);
+  OCR1AL = (uint8_t)((uint16_t)MATCH & 0xff);
+
+  /* Setup clock source and compare match behaviour. */
+
+  TCCR1A = 0x08 | PRESCALE;
+
+  /* Attach the timer interrupt vector */
+
+  (void)irq_attach(AT90USB_IRQ_T2COMPA, (xcpt_t)up_timerisr);
+
+  /* Enable the interrupt on compare match A */
+
+  TIMSK1 |= 0x10;
+}
diff --git a/nuttx/arch/avr/src/avr/up_initialstate.c b/nuttx/arch/avr/src/avr/up_initialstate.c
new file mode 100644
index 000000000..af7e88101
--- /dev/null
+++ b/nuttx/arch/avr/src/avr/up_initialstate.c
@@ -0,0 +1,110 @@
+/****************************************************************************
+ * arch/avr/src/avr/up_initialstate.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 <sys/types.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <nuttx/arch.h>
+#include <arch/irq.h>
+#include <avr/io.h>
+
+#include "up_internal.h"
+#include "up_arch.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_initial_state
+ *
+ * Description:
+ *   A new thread is being started and a new TCB has been created. This
+ *   function is called to initialize the processor specific portions of the
+ *   new TCB.
+ *
+ *   This function must setup the intial architecture registers and/or stack
+ *   so that execution will begin at tcb->start  on the next context switch.
+ *
+ ****************************************************************************/
+
+void up_initial_state(_TCB *tcb)
+{
+  struct xcptcontext *xcp = &tcb->xcp;
+
+  /* Initialize the initial exception register context structure.  Zeroing
+   * all registers is a good debug helper, but should not be necessary.
+   */
+
+  memset(xcp, 0, sizeof(struct xcptcontext));
+
+  /* Set the initial stack pointer to the "base" of the allocated stack */
+
+  xcp->regs[REG_SPH]   = (uint8_t)((uint16_t)tcb->adj_stack_ptr >> 8);
+  xcp->regs[REG_SPL]   = (uint8_t)((uint16_t)tcb->adj_stack_ptr & 0xff);
+
+  /* Save the task entry point */
+
+  xcp->regs[REG_PCH]   = (uint8_t)((uint16_t)tcb->start >> 8);
+  xcp->regs[REG_PCL]   = (uint8_t)((uint16_t)tcb->start & 0xff);
+
+  /* Enable or disable interrupts, based on user configuration */
+
+#ifdef CONFIG_SUPPRESS_INTERRUPTS
+  xcp->regs[REG_SREG]  = getsreg() & ~(1 << SREG_I);
+#else
+  xcp->regs[REG_SREG]  = getsreg() | (1 << SREG_I);
+#endif
+}
+
diff --git a/nuttx/arch/avr/src/avr/up_irq.c b/nuttx/arch/avr/src/avr/up_irq.c
new file mode 100644
index 000000000..11beee8e5
--- /dev/null
+++ b/nuttx/arch/avr/src/avr/up_irq.c
@@ -0,0 +1,108 @@
+/****************************************************************************
+ * arch/avr/src/avr/up_irq.c
+ *
+ *   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
+ * 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 "at90usb_config.h"
+
+#include <stdint.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/irq.h>
+#include <nuttx/arch.h>
+#include <arch/irq.h>
+#include <avr/io.h>
+
+#include "up_arch.h"
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+volatile uint8_t *current_regs;
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_irqinitialize
+ ****************************************************************************/
+
+void up_irqinitialize(void)
+{
+  /* currents_regs is non-NULL only while processing an interrupt */
+
+  current_regs = NULL;
+
+  /* Initialize GPIO interrupt facilities */
+
+#ifdef CONFIG_AVR32_GPIOIRQ
+#ifdef CONFIG_HAVE_WEAKFUNCTIONS
+  if (gpio_irqinitialize != NULL)
+#endif
+    {
+      gpio_irqinitialize();
+    }
+#endif
+
+  /* And finally, enable interrupts */
+
+#ifndef CONFIG_SUPPRESS_INTERRUPTS
+  irqrestore(getsreg() | (1 << SREG_I));
+#endif
+}
diff --git a/nuttx/arch/avr/src/avr/up_schedulesigaction.c b/nuttx/arch/avr/src/avr/up_schedulesigaction.c
index af9e917c6..ba56234d1 100644
--- a/nuttx/arch/avr/src/avr/up_schedulesigaction.c
+++ b/nuttx/arch/avr/src/avr/up_schedulesigaction.c
@@ -164,7 +164,7 @@ void up_schedule_sigaction(_TCB *tcb, sig_deliver_t sigdeliver)
 
               current_regs[REG_PCL]   = (uint16_t)up_sigdeliver & 0xff;
               current_regs[REG_PCH]   = (uint16_t)up_sigdeliver >> 8;
-              current_regs[REG_SREG] |= (1 << SREG_I);
+              current_regs[REG_SREG] &= ~(1 << SREG_I);
 
               /* And make sure that the saved context in the TCB
                * is the same as the interrupt return context.
@@ -198,7 +198,7 @@ void up_schedule_sigaction(_TCB *tcb, sig_deliver_t sigdeliver)
 
           tcb->xcp.regs[REG_PCL]    = (uint16_t)up_sigdeliver & 0xff;
           tcb->xcp.regs[REG_PCH]    = (uint16_t)up_sigdeliver >> 8;
-          tcb->xcp.regs[REG_SREG]  |= (1 << SREG_I);
+          tcb->xcp.regs[REG_SREG]  &= ~(1 << SREG_I);
         }
 
       irqrestore(flags);
diff --git a/nuttx/arch/avr/src/avr32/up_initialstate.c b/nuttx/arch/avr/src/avr32/up_initialstate.c
index 48dc6c8eb..38fe40d67 100644
--- a/nuttx/arch/avr/src/avr32/up_initialstate.c
+++ b/nuttx/arch/avr/src/avr32/up_initialstate.c
@@ -121,10 +121,10 @@ void up_initial_state(_TCB *tcb)
 
   /* Enable or disable interrupts, based on user configuration */
 
-# ifdef CONFIG_SUPPRESS_INTERRUPTS
+#ifdef CONFIG_SUPPRESS_INTERRUPTS
   xcp->regs[REG_SR]    = avr32_sr() | AVR32_SR_GM_MASK;
-# else
+#else
   xcp->regs[REG_SR]    = avr32_sr() & ~AVR32_SR_GM_MASK;
-# endif
+#endif
 }
 
diff --git a/nuttx/arch/avr/src/common/up_assert.c b/nuttx/arch/avr/src/common/up_assert.c
new file mode 100644
index 000000000..b2cd8ae86
--- /dev/null
+++ b/nuttx/arch/avr/src/common/up_assert.c
@@ -0,0 +1,154 @@
+/****************************************************************************
+ * arch/avr/src/common/up_assert.c
+ *
+ *   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
+ * 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 <stdlib.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <nuttx/irq.h>
+#include <nuttx/arch.h>
+#include <arch/board/board.h>
+
+#include "up_arch.h"
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* The following is just intended to keep some ugliness out of the mainline
+ * code.  We are going to print the task name if:
+ *
+ *  CONFIG_TASK_NAME_SIZE > 0 &&     <-- The task has a name
+ *  (defined(CONFIG_DEBUG)    ||     <-- And the debug is enabled (lldbg used)
+ *   defined(CONFIG_ARCH_STACKDUMP)) <-- Or lib_lowprintf() is used
+ */
+
+#undef CONFIG_PRINT_TASKNAME
+#if CONFIG_TASK_NAME_SIZE > 0 && (defined(CONFIG_DEBUG) || defined(CONFIG_ARCH_STACKDUMP))
+#  define CONFIG_PRINT_TASKNAME 1
+#endif
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: _up_assert
+ ****************************************************************************/
+
+static void _up_assert(int errorcode) /* __attribute__ ((noreturn)) */
+{
+  /* Are we in an interrupt handler or the idle task? */
+
+  if (current_regs || ((_TCB*)g_readytorun.head)->pid == 0)
+    {
+       (void)irqsave();
+        for(;;)
+          {
+#ifdef CONFIG_ARCH_LEDS
+            up_ledon(LED_PANIC);
+            up_mdelay(250);
+            up_ledoff(LED_PANIC);
+            up_mdelay(250);
+#endif
+          }
+    }
+  else
+    {
+      exit(errorcode);
+    }
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_assert
+ ****************************************************************************/
+
+void up_assert(const uint8_t *filename, int lineno)
+{
+#ifdef CONFIG_PRINT_TASKNAME
+  _TCB *rtcb = (_TCB*)g_readytorun.head;
+#endif
+
+  up_ledon(LED_ASSERTION);
+#ifdef CONFIG_PRINT_TASKNAME
+  lldbg("Assertion failed at file:%s line: %d task: %s\n",
+        filename, lineno, rtcb->name);
+#else
+  lldbg("Assertion failed at file:%s line: %d\n",
+        filename, lineno);
+#endif
+  up_dumpstate();
+  _up_assert(EXIT_FAILURE);
+}
+
+/****************************************************************************
+ * Name: up_assert_code
+ ****************************************************************************/
+
+void up_assert_code(const uint8_t *filename, int lineno, int errorcode)
+{
+#ifdef CONFIG_PRINT_TASKNAME
+  _TCB *rtcb = (_TCB*)g_readytorun.head;
+#endif
+
+  up_ledon(LED_ASSERTION);
+#ifdef CONFIG_PRINT_TASKNAME
+  lldbg("Assertion failed at file:%s line: %d task: %s error code: %d\n",
+        filename, lineno, rtcb->name, errorcode);
+#else
+  lldbg("Assertion failed at file:%s line: %d error code: %d\n",
+        filename, lineno, errorcode);
+#endif
+  up_dumpstate();
+  _up_assert(errorcode);
+}
+