README
^^^^^^
This README discusses issues unique to NuttX configurations for the
Atmel SAM3U-EK development board.
Contents
^^^^^^^^
- Development Environment
- GNU Toolchain Options
- IDEs
- NuttX buildroot Toolchain
- LEDs
- SAM3U-EK-specific Configuration Options
- Configurations
Development Environment
^^^^^^^^^^^^^^^^^^^^^^^
Either Linux or Cygwin on Windows can be used for the development environment.
The source has been built only using the GNU toolchain (see below). Other
toolchains will likely cause problems. Testing was performed using the Cygwin
environment.
GNU Toolchain Options
^^^^^^^^^^^^^^^^^^^^^
The NuttX make system has been modified to support the following different
toolchain options.
1. The CodeSourcery GNU toolchain,
2. The devkitARM GNU toolchain, ok
4. The NuttX buildroot Toolchain (see below).
All testing has been conducted using the NuttX buildroot toolchain. However,
the make system is setup to default to use the devkitARM toolchain. To use
the CodeSourcery, devkitARM or Raisonance GNU toolchain, you simply need to
add one of the following configuration options to your .config (or defconfig)
file:
CONFIG_SAM3U_CODESOURCERYW=y : CodeSourcery under Windows
CONFIG_SAM3U_CODESOURCERYL=y : CodeSourcery under Linux
CONFIG_SAM3U_DEVKITARM=y : devkitARM under Windows
CONFIG_SAM3U_BUILDROOT=y : NuttX buildroot under Linux or Cygwin (default)
If you are not using CONFIG_SAM3U_BUILDROOT, then you may also have to modify
the PATH in the setenv.h file if your make cannot find the tools.
NOTE: the CodeSourcery (for Windows), devkitARM, and Raisonance toolchains are
Windows native toolchains. The CodeSourcey (for Linux) and NuttX buildroot
toolchains are Cygwin and/or Linux native toolchains. There are several limitations
to using a Windows based toolchain in a Cygwin environment. The three biggest are:
1. The Windows toolchain cannot follow Cygwin paths. Path conversions are
performed automatically in the Cygwin makefiles using the 'cygpath' utility
but you might easily find some new path problems. If so, check out 'cygpath -w'
2. Windows toolchains cannot follow Cygwin symbolic links. Many symbolic links
are used in Nuttx (e.g., include/arch). The make system works around these
problems for the Windows tools by copying directories instead of linking them.
But this can also cause some confusion for you: For example, you may edit
a file in a "linked" directory and find that your changes had not effect.
That is because you are building the copy of the file in the "fake" symbolic
directory. If you use a Windows toolchain, you should get in the habit of
making like this:
make clean_context all
An alias in your .bashrc file might make that less painful.
3. Dependencies are not made when using Windows versions of the GCC. This is
because the dependencies are generated using Windows pathes which do not
work with the Cygwin make.
Support has been added for making dependencies with the windows-native toolchains.
That support can be enabled by modifying your Make.defs file as follows:
- MKDEP = $(TOPDIR)/tools/mknulldeps.sh
+ MKDEP = $(TOPDIR)/tools/mkdeps.sh --winpaths "$(TOPDIR)"
If you have problems with the dependency build (for example, if you are not
building on C:), then you may need to modify tools/mkdeps.sh
NOTE 1: The CodeSourcery toolchain (2009q1) does not work with default optimization
level of -Os (See Make.defs). It will work with -O0, -O1, or -O2, but not with
-Os.
NOTE 2: The devkitARM toolchain includes a version of MSYS make. Make sure that
the paths to Cygwin's /bin and /usr/bin directories appear BEFORE the devkitARM
path or will get the wrong version of make.
IDEs
^^^^
NuttX is built using command-line make. It can be used with an IDE, but some
effort will be required to create the project (There is a simple RIDE project
in the RIDE subdirectory). Here are a few tip before you start that effort:
1) Select the toolchain that you will be using in your .config file
2) Start the NuttX build at least one time from the Cygwin command line
before trying to create your project. This is necessary to create
certain auto-generated files and directories that will be needed.
3) Set up include pathes: You will need include/, arch/arm/src/sam3u,
arch/arm/src/common, arch/arm/src/cortexm3, and sched/.
4) All assembly files need to have the definition option -D __ASSEMBLY__
on the command line.
Startup files will probably cause you some headaches. The NuttX startup file
is arch/arm/src/sam3u/sam3u_vectors.S. You may need to build NuttX
one time from the Cygwin command line in order to obtain the pre-built
startup object needed by RIDE.
NuttX buildroot Toolchain
^^^^^^^^^^^^^^^^^^^^^^^^^
A GNU GCC-based toolchain is assumed. The files */setenv.sh should
be modified to point to the correct path to the Cortex-M3 GCC toolchain (if
different from the default in your PATH variable).
If you have no Cortex-M3 toolchain, one can be downloaded from the NuttX
SourceForge download site (https://sourceforge.net/project/showfiles.php?group_id=189573).
This GNU toolchain builds and executes in the Linux or Cygwin environment.
1. You must have already configured Nuttx in <some-dir>/nuttx.
cd tools
./configure.sh sam3u-ek/<sub-dir>
2. Download the latest buildroot package into <some-dir>
3. unpack the buildroot tarball. The resulting directory may
have versioning information on it like buildroot-x.y.z. If so,
rename <some-dir>/buildroot-x.y.z to <some-dir>/buildroot.
4. cd <some-dir>/buildroot
5. cp configs/cortexm3-defconfig-4.3.3 .config
6. make oldconfig
7. make
8. Edit setenv.h, if necessary, so that the PATH variable includes
the path to the newly built binaries.
See the file configs/README.txt in the buildroot source tree. That has more
detailed PLUS some special instructions that you will need to follow if you are
building a Cortex-M3 toolchain for Cygwin under Windows.
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 interupts that result in the LED being illuminated
on a small proportion of the time.
*** LED2 may also flicker normally if signals are processed.
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=sam3u
CONFIG_ARCH_CHIP_name - For use in C code to identify the exact
chip:
CONFIG_ARCH_CHIP_AT91SAM3U4
CONFIG_ARCH_BOARD - Identifies the configs 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_DRAM_SIZE - Describes the installed DRAM (SRAM in this case):
CONFIG_DRAM_SIZE=0x0000c000 (48Kb)
CONFIG_DRAM_START - The start address of installed DRAM
CONFIG_DRAM_START=0x20000000
CONFIG_DRAM_END - Last address+1 of installed RAM
CONFIG_DRAM_END=(CONFIG_DRAM_START+CONFIG_DRAM_SIZE)
CONFIG_ARCH_IRQPRIO - The SAM3UF103Z supports interrupt prioritization
CONFIG_ARCH_IRQPRIO=y
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.
CONFIG_ARCH_CALIBRATION - Enables some build in instrumentation that
cause a 100 second delay during boot-up. This 100 second delay
serves no purpose other than it allows you to calibratre
CONFIG_ARCH_LOOPSPERMSEC. You simply use a stop watch to measure
the 100 second delay then adjust CONFIG_ARCH_LOOPSPERMSEC until
the delay actually is 100 seconds.
Individual subsystems can be enabled:
CONFIG_SAM3U_DMA
CONFIG_SAM3U_NAND
CONFIG_SAM3U_HSMCI
CONFIG_SAM3U_UART
CONFIG_SAM3U_USART0
CONFIG_SAM3U_USART1
CONFIG_SAM3U_USART2
CONFIG_SAM3U_USART3
Some subsystems can be configured to operate in different ways. The drivers
need to know how to configure the subsystem.
CONFIG_GPIOA_IRQ
CONFIG_GPIOB_IRQ
CONFIG_GPIOC_IRQ
CONFIG_USART0_ISUART
CONFIG_USART1_ISUART
CONFIG_USART2_ISUART
CONFIG_USART3_ISUART
AT91SAM3U 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
Configurations
^^^^^^^^^^^^^^
Each SAM3U-EK configuration is maintained in a sudirectory and
can be selected as follow:
cd tools
./configure.sh sam3u-ek/<subdir>
cd -
. ./setenv.sh
Where <subdir> is one of the following:
nsh:
Configures the NuttShell (nsh) located at examples/nsh. The
Configuration enables both the serial and telnetd NSH interfaces.
nx
Configures to use examples/nx using the HX834x LCD hardwar on
the SAM3U-EK development board.
ostest:
This configuration directory, performs a simple OS test using
examples/ostest. By default, this project assumes that you are
using the DFU bootloader.
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