README
^^^^^^

This README discusses issues unique to NuttX configurations for the Atmel
SAM3U-EK development board featuring the ATAM3U.  This board features the
ATSAM3U4E MCU running at 96MHz.

Contents
^^^^^^^^

  - AtmelStudio 6.1
  - LEDs
  - Serial Console
  - SAM3U-EK-specific Configuration Options
  - Configurations

AtmelStudio 6.1
^^^^^^^^^^^^^^^

  You can use AtmelStudio6.1 to load and debug code.

  - To load code:

    Tools -> Device Programming

    Configure the debugger and chip and you are in business.

  - To Debug Code:

    File -> Open -> Open Object File for Debugging

    Select the project name, the full path to the NuttX object (called
    just nuttx with no extension), and chip.  Take the time to resolve
    all of the source file linkages or else you will not have source
    level debug!

LEDs
^^^^

  The SAM3U-EK board has four LEDs labeled LD1, LD2, LD3 and LD4 on the
  the board.  Usage of these LEDs is defined in include/board.h and src/up_leds.c.
  They are encoded as follows:

    SYMBOL              Meaning                 LED0*   LED1    LED2
    ------------------- ----------------------- ------- ------- -------
    LED_STARTED         NuttX has been started  OFF     OFF     OFF
    LED_HEAPALLOCATE    Heap has been allocated OFF     OFF     ON
    LED_IRQSENABLED     Interrupts enabled      OFF     ON      OFF
    LED_STACKCREATED    Idle stack created      OFF     ON      ON
    LED_INIRQ           In an interrupt**       N/C     FLASH   N/C
    LED_SIGNAL          In a signal handler***  N/C     N/C     FLASH
    LED_ASSERTION       An assertion failed     FLASH   N/C     N/C
    LED_PANIC           The system has crashed  FLASH   N/C     N/C

  * If LED1 and LED2 are statically on, then NuttX probably failed to boot
    and these LEDs will give you some indication of where the failure was
 ** The normal state is LED0=OFF, LED2=ON and LED1 faintly glowing.  This faint
    glow is because of timer interrupts that result in the LED being illuminated
    on a small proportion of the time.
*** LED2 may also flicker normally if signals are processed.

Serial Console
^^^^^^^^^^^^^^

  By default, all of these configurations use UART0 for the NuttX serial
  console.  UART0 corresponds to the DB-9 connector labelled "UART".  This
  is a male connector and will require a female-to-female, NUL modem cable
  to connect to a PC.

  An alternate is USART1 which connects to the other DB-9 connector labeled
  "USART".  USART1 is not enabled by default unless specifically noted
  otherwise in the configuration description.  A NUL modem cable must be
  used with the port as well.

  NOTE:  One of the USART1 pins is shared with the audio CODEC.  The audio
  CODEC cannot be used of USART1 is enabled.

  By default serial console is configured for 115000, 8-bit, 1 stop bit, and
  no parity.

SAM3U-EK-specific Configuration Options
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    CONFIG_ARCH - Identifies the arch/ subdirectory.  This should
       be set to:

       CONFIG_ARCH=arm

    CONFIG_ARCH_family - For use in C code:

       CONFIG_ARCH_ARM=y

    CONFIG_ARCH_architecture - For use in C code:

       CONFIG_ARCH_CORTEXM3=y

    CONFIG_ARCH_CHIP - Identifies the arch/*/chip subdirectory

       CONFIG_ARCH_CHIP="sam34"

    CONFIG_ARCH_CHIP_name - For use in C code to identify the exact
       chip:

       CONFIG_ARCH_CHIP_SAM34
       CONFIG_ARCH_CHIP_SAM3U
       CONFIG_ARCH_CHIP_ATSAM3U4

    CONFIG_ARCH_BOARD - Identifies the boards/ subdirectory and
       hence, the board that supports the particular chip or SoC.

       CONFIG_ARCH_BOARD=sam3u-ek (for the SAM3U-EK development board)

    CONFIG_ARCH_BOARD_name - For use in C code

       CONFIG_ARCH_BOARD_SAM3UEK=y

    CONFIG_ARCH_LOOPSPERMSEC - Must be calibrated for correct operation
       of delay loops

    CONFIG_ENDIAN_BIG - define if big endian (default is little
       endian)

    CONFIG_RAM_SIZE - Describes the installed DRAM (SRAM in this case):

       CONFIG_RAM_SIZE=0x0000c000 (48Kb)

    CONFIG_RAM_START - The start address of installed DRAM

       CONFIG_RAM_START=0x20000000

    CONFIG_ARCH_LEDS - Use LEDs to show state. Unique to boards that
       have LEDs

    CONFIG_ARCH_INTERRUPTSTACK - This architecture supports an interrupt
       stack. If defined, this symbol is the size of the interrupt
        stack in bytes.  If not defined, the user task stacks will be
      used during interrupt handling.

    CONFIG_ARCH_STACKDUMP - Do stack dumps after assertions

    CONFIG_ARCH_LEDS -  Use LEDs to show state. Unique to board architecture.

  Individual subsystems can be enabled:

    CONFIG_SAM34_RTC           - Real Time Clock
    CONFIG_SAM34_RTT           - Real Time Timer
    CONFIG_SAM34_WDT           - Watchdog Timer
    CONFIG_SAM34_UART0         - UART 0
    CONFIG_SAM34_SMC           - Static Memory Controller
    CONFIG_SAM34_USART0        - USART 0
    CONFIG_SAM34_USART1        - USART 1
    CONFIG_SAM34_USART2        - USART 2
    CONFIG_SAM34_USART3        - USART 3
    CONFIG_SAM34_HSMCI         - High Speed Multimedia Card Interface
    CONFIG_SAM34_TWI0          - Two-Wire Interface 0
    CONFIG_SAM34_TWI1          - Two-Wire Interface 1
    CONFIG_SAM34_SPI0           - Serial Peripheral Interface
    CONFIG_SAM34_SSC           - Synchronous Serial Controller
    CONFIG_SAM34_TC0           - Timer Counter 0
    CONFIG_SAM34_TC1           - Timer Counter 1
    CONFIG_SAM34_TC2           - Timer Counter 2
    CONFIG_SAM34_PWM           - Pulse Width Modulation Controller
    CONFIG_SAM34_ADC12B        - 12-bit ADC Controller
    CONFIG_SAM34_ADC           - 10-bit ADC Controller
    CONFIG_SAM34_DMAC0         - DMA Controller
    CONFIG_SAM34_UDPHS         - USB Device High Speed

  Some subsystems can be configured to operate in different ways. The drivers
  need to know how to configure the subsystem.

    CONFIG_SAM34_GPIOA_IRQ
    CONFIG_SAM34_GPIOB_IRQ
    CONFIG_SAM34_GPIOC_IRQ
    CONFIG_USART0_SERIALDRIVER
    CONFIG_USART1_SERIALDRIVER
    CONFIG_USART2_SERIALDRIVER
    CONFIG_USART3_SERIALDRIVER
    CONFIG_SAM34_NAND          - NAND memory

  SAM3U specific device driver settings

    CONFIG_U[S]ARTn_SERIAL_CONSOLE - selects the USARTn (n=0,1,2,3) or UART
           m (m=4,5) for the console and ttys0 (default is the USART1).
    CONFIG_U[S]ARTn_RXBUFSIZE - Characters are buffered as received.
       This specific the size of the receive buffer
    CONFIG_U[S]ARTn_TXBUFSIZE - Characters are buffered before
       being sent.  This specific the size of the transmit buffer
    CONFIG_U[S]ARTn_BAUD - The configure BAUD of the UART.  Must be
    CONFIG_U[S]ARTn_BITS - The number of bits.  Must be either 7 or 8.
    CONFIG_U[S]ARTn_PARTIY - 0=no parity, 1=odd parity, 2=even parity
    CONFIG_U[S]ARTn_2STOP - Two stop bits

  LCD Options.  Other than the standard LCD configuration options
  (see boards/README.txt), the SAM3U-EK driver also supports:

    CONFIG_LCD_PORTRAIT - Present the display in the standard 240x320
       "Portrait" orientation.  Default:  The display is rotated to
       support a 320x240 "Landscape" orientation.

Configurations
^^^^^^^^^^^^^^

  Information Common to All Configurations
  ----------------------------------------
  Each SAM3U-EK configuration is maintained in a sub-directory and
  can be selected as follow:

    tools/configure.sh sam3u-ek:<subdir>

  Before building, make sure the PATH environment variable includes the
  correct path to the directory than holds your toolchain binaries.

  And then build NuttX by simply typing the following.  At the conclusion of
  the make, the nuttx binary will reside in an ELF file called, simply, nuttx.

    make

  The <subdir> that is provided above as an argument to the tools/configure.sh
  must be is one of the following.

  NOTES:

  1. These configurations use the mconf-based configuration tool.  To
    change any of these configurations using that tool, you should:

    a. Build and install the kconfig-mconf tool.  See nuttx/README.txt
       see additional README.txt files in the NuttX tools repository.

    b. Execute 'make menuconfig' in nuttx/ in order to start the
       reconfiguration process.

  2. Unless stated otherwise, all configurations generate console
     output on UART0 (J3).

  3. Unless otherwise stated, the configurations are setup for
     Linux (or any other POSIX environment like Cygwin under Windows):

     Build Setup:
       CONFIG_HOST_LINUX=y   : Linux or other POSIX environment

  4. All of these configurations use the older, OABI, buildroot toolchain
     (unless stated otherwise in the description of the configuration).  That
     toolchain selection can easily be reconfigured using 'make menuconfig'.
     Here are the relevant current settings:

     Build Setup:
       CONFIG_HOST_LINUX=y                 : Linux or other pure POSIX invironment
                                           : (including Cygwin)
     System Type -> Toolchain:
       CONFIG_ARM_TOOLCHAIN_BUILDROOT=y : Buildroot toolchain
       CONFIG_ARM_TOOLCHAIN_BUILDROOT_OABI=y      : Older, OABI toolchain

     If you want to use the Atmel GCC toolchain, for example, here are the
     steps to do so:

     Build Setup:
       CONFIG_HOST_WINDOWS=y   : Windows
       CONFIG_HOST_CYGWIN=y    : Using Cygwin or other POSIX environment

     System Type -> Toolchain:
       CONFIG_ARM_TOOLCHAIN_GNU_EABI=y  : General GCC EABI toolchain under windows

     Library Routines ->
       CONFIG_ARCH_SIZET_LONG=n            : size_t is an unsigned int, not long

     This re-configuration should be done before making NuttX or else the
     subsequent 'make' will fail.  If you have already attempted building
     NuttX then you will have to 1) 'make distclean' to remove the old
     configuration, 2) 'tools/configure.sh sam3u-ek/ksnh' to start
     with a fresh configuration, and 3) perform the configuration changes
     above.

     Also, make sure that your PATH variable has the new path to your
     Atmel tools.  Try 'which arm-none-eabi-gcc' to make sure that you
     are selecting the right tool.

     See also the "NOTE about Windows native toolchains" in the section call
     "GNU Toolchain Options" above.

  Configuration sub-directories
  -----------------------------

  knsh:
    This is identical to the nsh configuration below except that NuttX
    is built as a kernel-mode, monolithic module and the user applications
    are built separately.  It is recommends to use a special make command;
    not just 'make' but make with the following two arguments:

        make pass1 pass2

    In the normal case (just 'make'), make will attempt to build both user-
    and kernel-mode blobs more or less interleaved.  This actual works!
    However, for me it is very confusing so I prefer the above make command:
    Make the user-space binaries first (pass1), then make the kernel-space
    binaries (pass2)

    NOTES:

    1. At the end of the build, there will be several files in the top-level
       NuttX build directory:

       PASS1:
         nuttx_user.elf    - The pass1 user-space ELF file
         nuttx_user.hex    - The pass1 Intel HEX format file (selected in defconfig)
         User.map          - Symbols in the user-space ELF file

       PASS2:
         nuttx             - The pass2 kernel-space ELF file
         nuttx.hex         - The pass2 Intel HEX file (selected in defconfig)
         System.map        - Symbols in the kernel-space ELF file

       The J-Link programmer will except files in .hex, .mot, .srec, and .bin
       formats.

    2. Combining .hex files.  If you plan to use the .hex files with your
       debugger or FLASH utility, then you may need to combine the two hex
       files into a single .hex file.  Here is how you can do that.

       a. The 'tail' of the nuttx.hex file should look something like this
          (with my comments added):

            $ tail nuttx.hex
            # 00, data records
            ...
            :10 9DC0 00 01000000000800006400020100001F0004
            :10 9DD0 00 3B005A0078009700B500D400F300110151
            :08 9DE0 00 30014E016D0100008D
            # 05, Start Linear Address Record
            :04 0000 05 0800 0419 D2
            # 01, End Of File record
            :00 0000 01 FF

          Use an editor such as vi to remove the 05 and 01 records.

       b. The 'head' of the nuttx_user.hex file should look something like
          this (again with my comments added):

            $ head nuttx_user.hex
            # 04, Extended Linear Address Record
            :02 0000 04 0801 F1
            # 00, data records
            :10 8000 00 BD89 01084C800108C8110208D01102087E
            :10 8010 00 0010 00201C1000201C1000203C16002026
            :10 8020 00 4D80 01085D80010869800108ED83010829
            ...

          Nothing needs to be done here.  The nuttx_user.hex file should
          be fine.

       c. Combine the edited nuttx.hex and un-edited nuttx_user.hex
          file to produce a single combined hex file:

          $ cat nuttx.hex nuttx_user.hex >combined.hex

       Then use the combined.hex file with the to write the FLASH image.
       If you do this a lot, you will probably want to invest a little time
       to develop a tool to automate these steps.

  nsh:
    Configures the NuttShell (nsh) located at examples/nsh.  The
    Configuration enables both the serial and telnetd NSH interfaces.

    NOTES:

    1. NSH built-in applications are supported.  However, there are
       no built-in applications built with the default configuration.

       Binary Formats:
         CONFIG_BUILTIN=y                    : Enable support for built-in programs

       Application Configuration:
         CONFIG_NSH_BUILTIN_APPS=y           : Enable starting apps from NSH command line

    2. This configuration has been used for verifying the touchscreen on
       on the SAM3U-EK LCD.  With these modifications, you can include the
       touchscreen test program at apps/examples/touchscreen as an NSH built-in
       application.  You can enable the touchscreen and test by modifying the
       default configuration in the following ways:

          Device Drivers
            CONFIG_SPI=y                      : Enable SPI support
            CONFIG_SPI_EXCHANGE=y             : The exchange() method is supported

            CONFIG_INPUT=y                    : Enable support for input devices
            CONFIG_INPUT_ADS7843E=y           : Enable support for the XPT2046
            CONFIG_ADS7843E_SPIDEV=2          : Use SPI CS 2 for communication
            CONFIG_ADS7843E_SPIMODE=0         : Use SPI mode 0
            CONFIG_ADS7843E_FREQUENCY=1000000 : SPI BAUD 1MHz
            CONFIG_ADS7843E_SWAPXY=y          : If landscpe orientation
            CONFIG_ADS7843E_THRESHX=51        : These will probably need to be tuned
            CONFIG_ADS7843E_THRESHY=39

          System Type -> Peripherals:
            CONFIG_SAM34_SPI0=y               : Enable support for SPI

          System Type:
            CONFIG_SAM34_GPIO_IRQ=y           : GPIO interrupt support
            CONFIG_SAM34_GPIOA_IRQ=y          : Enable GPIO interrupts from port A

          Library Support:
            CONFIG_SCHED_WORKQUEUE=y          : Work queue support required

          Application Configuration:
            CONFIG_EXAMPLES_TOUCHSCREEN=y     : Enable the touchscreen built-int test

          Defaults should be okay for related touchscreen settings.  Touchscreen
          debug output on UART0 can be enabled with:

          Build Setup:
            CONFIG_DEBUG_FEATURES=y           : Enable debug features
            CONFIG_DEBUG_INFO=y               : Enable verbose debug output
            CONFIG_DEBUG_INPUT=y              : Enable debug output from input devices

    3. Enabling HSMCI support. The SAM3U-KE provides a an SD memory card
       slot.  Support for the SD slot can be enabled with the following
       settings:

       System Type->ATSAM3/4 Peripheral Support
         CONFIG_SAM34_HSMCI=y                 : Enable HSMCI support
         CONFIG_SAM34_DMAC0=y                 : DMAC support is needed by HSMCI

       System Type
         CONFIG_SAM34_GPIO_IRQ=y              : PIO interrupts needed
         CONFIG_SAM34_GPIOA_IRQ=y             : Card detect pin is on PIOA

       Device Drivers -> MMC/SD Driver Support
         CONFIG_MMCSD=y                       : Enable MMC/SD support
         CONFIG_MMSCD_NSLOTS=1                : One slot per driver instance
         CONFIG_MMCSD_HAVE_CARDDETECT=y        : Supports card-detect PIOs
         CONFIG_MMCSD_SDIO=y                  : SDIO-based MMC/SD support
         CONFIG_SDIO_DMA=y                    : Use SDIO DMA
         CONFIG_SDIO_BLOCKSETUP=y             : Needs to know block sizes

       Library Routines
         CONFIG_SCHED_WORKQUEUE=y             : Driver needs work queue support

       Application Configuration -> NSH Library
         CONFIG_NSH_ARCHINIT=y                : NSH board-initialization

    STATUS:
      2013-6-28: The touchscreen is functional.
      2013-6-29: Hmmm... but there appear to be conditions when the
        touchscreen driver locks up.  Looks like some issue with
        managing the interrupts.
      2013-6-30:  Those lock-ups appear to be due to poorly placed
        debug output statements.  If you do not enable debug output,
        the touchscreen is rock-solid.
      2013-8-10:  Added the comments above above enabling HSMCI memory
        card support and verified that the configuration builds without
        error.  However, that configuration has not yet been tested (and
        is may even be incomplete).

  nx:
    Configures to use examples/nx using the HX834x LCD hardware on
    the SAM3U-EK development board.

  nxwm:
    This is a special configuration setup for the NxWM window manager
    UnitTest.  It includes support for both the HX834x LCD and the
    ADS7843E touchscreen controller on board the SAM3U-EK board.

    The NxWM window manager is a tiny window manager tailored for use
    with smaller LCDs.  It supports a toolchain, a start window, and
    multiple application windows.  However, to make the best use of
    the visible LCD space, only one application window is visible at
    at time.

    The NxWM window manager can be found here:

      apps/graphics/NxWidgets/nxwm

    The NxWM unit test can be found at:

      apps/graphics/NxWidgets/UnitTests/nxwm

    STATUS:

    1. 2013-6-28:  Created the configuration but have not yet done
       anything with it.

    2. 2013-6-29:  Various changes to get a clean build of this
       configuration. Still untested.

    3. 20113-6-30:  I cannot load this program using AtmelStudio6.1.
       The total size with DEBUG on is 138.9 KB.  I have verified
       that the first 128KB may have been written correctly, but then
       the code above 128KB wraps and overwrites the code at the
       beginning of FLASH, trashing the FLASH images.

       Bottom line:  Still untested.
