README
^^^^^^
This README file discusses the port of NuttX to the Embedded Artists
EA3131 board.
Contents
^^^^^^^^
o Development Environment
o GNU Toolchain Options
o IDEs
o NuttX buildroot Toolchain
o Boot Sequence
o Image Format
o Image Download to ISRAM
o Using OpenOCD and GDB
o ARM/EA3131-specific Configuration Options
o 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.
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,
3. Raisonance GNU toolchain, or
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_LPC313X_CODESOURCERYW=y : CodeSourcery under Windows
CONFIG_LPC313X_CODESOURCERYL=y : CodeSourcery under Linux
CONFIG_LPC313X_DEVKITARM=y : devkitARM under Windows
CONFIG_LPC313X_RAISONANCE=y : Raisonance RIDE7 under Windows
CONFIG_LPC313X_BUILDROOT=y : NuttX buildroot under Linux or Cygwin (default)
If you are not using CONFIG_LPC313X_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/lpc313x,
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/lpc313x/lpc313x_vectors.S. With RIDE, I have 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 ea3131/<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/arm926t-defconfig-4.2.4 .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.
Boot Sequence
^^^^^^^^^^^^^
LPC313x has on chip bootrom which loads properly formatted images from multiple
sources into SRAM. These sources include including SPI Flash, NOR Flash, UART,
USB, SD Card, and NAND Flash.
In all configurations, NuttX is loaded directly into ISRAM. NuttX is linked
to execute from ISRAM, regardless of the boot source.
Image Format
^^^^^^^^^^^^
In order to use the bootrom bootloader, a special header must be added to the
beginning of the binary image that includes information about the binary (things
like the entry point, the size, and CRC's to verify the image.
NXP provides a Windows program to append such a header to the binary image.
However, (1) that program won't run under Linux, and (2) when I try it under
WinXP, Symantec immediately claims that the program is misbehaving and deletes
it!
To work around both of these issues, I have created a small program under
configs/ea3131/tools to add the header. This program can be built under
either Linux or Cygwin (and probably other tool environments as well). That
tool can be built as follows:
- cd configs/ea3131/tools
- make
Then, to build the NuttX binary ready to load with the bootloader, just
following these steps:
- cd tools/ # Configure Nuttx
- ./configure.sh ea3131/ostest # (using the ostest configuration for this example)
- cd .. # Set up environment
- . ./setenv.sh # (see notes below)
- make # Make NuttX. This will produce nuttx.bin
- mklpc.sh # Make the bootloader binary (nuttx.lpc)
NOTES:
1. setenv.sh just sets up pathes to the toolchain and also to
configs/ea3131/tools where mklpc.sh resides. Use of setenv.sh is optional.
If you don't use setenv.sh, then just set your PATH variable appropriately or
use the full path to mklpc.sh in the final step.
2. You can't instruct Symantec to ignore the errors and it will stop quarantining
the NXP program.
3. The CRC32 logic in configs/ea3131/tools doesn't seem to work. As a result,
the CRC is currently disabled in the header:
RCS file: /cvsroot/nuttx/nuttx/configs/ea3131/tools/lpchdr.c,v
retrieving revision 1.2
diff -r1.2 lpchdr.c
264c264
< g_hdr.imageType = 0x0000000b;
---
> g_hdr.imageType = 0x0000000a;
Image Download to ISRAM
^^^^^^^^^^^^^^^^^^^^^^^
Assuming that you already have the FTDI driver installed*, then here is the
are the steps that I use for loading new code into the EA3131:
- Create the bootloader binary, nuttx.lpc, as described above.
- Connected the EA3131 using the FTDI USB port (not the lpc3131 USB port)
This will power up the EA3131 and start the bootloader.
- Start a terminal emulator (such as TeraTerm) at 115200 8NI.
- Reset the EA3131 and you should see:
LPC31xx READY FOR PLAIN IMAGE>
- Send the nuttx.lpc file and you should see:
Download finished
That will load the NuttX binary into ISRAM and attempt to execute it.
*See the LPC313x documentation if you do not have the FTDI driver installed.
Using OpenOCD and GDB
^^^^^^^^^^^^^^^^^^^^^
I have been using the Olimex ARM-USB-OCD JTAG debugger with the EA3131
(http://www.olimex.com). The OpenOCD configuration file is here:
tools/armusbocb.cfg. There is also a script on the tools directory that
I used to start the OpenOCD daemon on my system called oocd.sh. That
script would probably require some modifications to work in another
environment:
- possibly the value of OPENOCD_PATH
- If you are working under Linux you will need to change any
occurances of `cygpath -w blablabla` to just blablabla
Then you should be able to start the OpenOCD daemon like:
configs/ea3131/tools/oocd.sh $PWD
Where it is assumed that you are executing oocd.sh from the top level
directory where NuttX is installed.
Once the OpenOCD daemon has been started, you can connect to it via
GDB using the following GDB command:
arm-elf-gdb
(gdb) target remote localhost:3333
And you can load the NuttX ELF file:
(gdb) symbol-file nuttx
(gdb) load nuttx
ARM/EA3131-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_ARM926EJS=y
CONFIG_ARCH_CHIP - Identifies the arch/*/chip subdirectory
CONFIG_ARCH_CHIP=lpc313x
CONFIG_ARCH_CHIP_name - For use in C code
CONFIG_ARCH_CHIP_LPC3131
CONFIG_ARCH_BOARD - Identifies the configs subdirectory and
hence, the board that supports the particular chip or SoC.
CONFIG_ARCH_BOARD=ea3131
CONFIG_ARCH_BOARD_name - For use in C code
CONFIG_ARCH_BOARD_EA3131
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 - For most ARM9 architectures, this describes the
size of installed DRAM. For the LPC313X, it is used only to
deterimine how to map the executable regions. It is SDRAM size
only if you are executing out of the external SDRAM; or it could
be NOR FLASH size, external SRAM size, or internal SRAM size.
CONFIG_DRAM_START - The start address of installed DRAM (physical)
CONFIG_DRAM_VSTART - The startaddress of DRAM (virtual)
CONFIG_ARCH_LEDS - Use LEDs to show state. Unique to boards that
have LEDs
CONFIG_ARCH_IRQPRIO - The LPC313x supports interrupt prioritization
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_BOOTLOADER - Set if you are using a bootloader.
CONFIG_ARCH_LEDS - Use LEDs to show state. Unique to board architecture.
CONFIG_ARCH_BUTTONS - Enable support for buttons. 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.
CONFIG_ARCH_DMA - Support DMA initialization
CONFIG_ARCH_LOWVECTORS - define if vectors reside at address 0x0000:00000
Undefine if vectors reside at address 0xffff:0000
CONFIG_ARCH_ROMPGTABLE - A pre-initialized, read-only page table is available.
If defined, then board-specific logic must also define PGTABLE_BASE_PADDR,
PGTABLE_BASE_VADDR, and all memory section mapping in a file named
board_memorymap.h.
Individual subsystems can be enabled:
CONFIG_LPC313X_MCI, CONFIG_LPC313X_SPI, CONFIG_LPC313X_UART
xernal memory available on the board (see also CONFIG_MM_REGIONS)
CONFIG_LPC313X_EXTSRAM0 - Select if external SRAM0 is present
CONFIG_LPC313X_EXTSRAM0HEAP - Select if external SRAM0 should be
configured as part of the NuttX heap.
CONFIG_LPC313X_EXTSRAM0SIZE - Size (in bytes) of the installed
external SRAM0 memory
CONFIG_LPC313X_EXTSRAM1 - Select if external SRAM1 is present
CONFIG_LPC313X_EXTSRAM1HEAP - Select if external SRAM1 should be
configured as part of the NuttX heap.
CONFIG_LPC313X_EXTSRAM1SIZE - Size (in bytes) of the installed
external SRAM1 memory
CONFIG_LPC313X_EXTSDRAM - Select if external SDRAM is present
CONFIG_LPC313X_EXTSDRAMHEAP - Select if external SDRAM should be
configured as part of the NuttX heap.
CONFIG_LPC313X_EXTSDRAMSIZE - Size (in bytes) of the installed
external SDRAM memory
CONFIG_LPC313X_EXTNAND - Select if external NAND is present
CONFIG_LPC313X_EXTSDRAMSIZE - Size (in bytes) of the installed
external NAND memory
LPC313X specific device driver settings
CONFIG_UART_SERIAL_CONSOLE - selects the UART for the
console and ttys0
CONFIG_UART_RXBUFSIZE - Characters are buffered as received.
This specific the size of the receive buffer
CONFIG_UART_TXBUFSIZE - Characters are buffered before
being sent. This specific the size of the transmit buffer
CONFIG_UART_BAUD - The configure BAUD of the UART. Must be
CONFIG_UART_BITS - The number of bits. Must be either 7 or 8.
CONFIG_UART_PARTIY - 0=no parity, 1=odd parity, 2=even parity
CONFIG_UART_2STOP - Two stop bits
Configurations
^^^^^^^^^^^^^^
Each EA3131 configuration is maintained in a sudirectory and can be
selected as follow:
cd tools
./configure.sh ea3131/<subdir>
cd -
. ./setenv.sh
Where <subdir> is one of the following:
nsh:
Configures the NuttShell (nsh) located at examples/nsh. The
Configuration enables only the serial NSH interface.
ostest:
This configuration directory, performs a simple OS test using
examples/ostest. By default, this project assumes that you are
using the DFU bootloader.
usbserial:
This configuration directory exercises the USB serial class
driver at examples/usbserial. See examples/README.txt for
more information.
usbstorage:
This configuration directory exercises the USB mass storage
class driver at examples/usbstorage. See examples/README.txt for
more information.
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