README
^^^^^^
This README discusses issues unique to NuttX configurations for the
MCU-123 LPC2148 development board.
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 NuttX buildroot Toolchain (see below).
2. The CodeSourcery GNU toolchain,
3. The devkitARM GNU toolchain, or
All testing has been conducted using the NuttX buildroot toolchain. To use
the CodeSourcery or devkitARM GNU toolchain, you simply need to build the
system as follows:
make # Will build for the NuttX buildroot toolchain
make CROSSDEV=arm-eabi- # Will build for the devkitARM toolchain
make CROSSDEV=arm-none-eabi- # Will build for the CodeSourcery toolchain
make CROSSDEV=arm-elf- # Will build for the NuttX buildroot toolchain
Of course, hard coding this CROSS_COMPILE value in Make.defs file will save
some repetitive typing.
NOTE: the CodeSourcery and devkitARM toolchains are Windows native toolchains.
The NuttX buildroot toolchain is a Cygwin toolchain. 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; make CROSSDEV=arm-none-eabi-
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 CodeSourcery toolchain.
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) may 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.
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 eagle100/<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.
Flash Tools
^^^^^^^^^^^
I use the lpc21isp tool to load NuttX into FLASH. That tool is available
in the files section at http://tech.groups.yahoo.com/group/lpc21isp/. In
order version 1.60 of lpc21isp for Linux, I had to make several changes.
This changes are shown in lpc21ips-1.60.diff.
I use the script lpc21isp.sh to perform the actual download. You will
probably have to make some changes to this script in order to use it.
For example, the path to the built lpc21isp binary will most likely
have to change. Then move this script to the top level NuttX
directory and simply execute it to load NuttX onto the board (after
entering ISP mode).
Here are the detailed steps I use:
1. Make sure you exit minicom (or whatever terminal emulator you are
using). It will interfere with the download.
2. On the MCU123 board, I need to put a jumper on JP3-INT. On that board,
JP3-INT is connected to P0.14 of LPC214x. When P0.14 is low and RTS is
changed from high to low, the LPC214x will enter ISP (In System Programming)
state.
3. start lpc21isp.sh
4. reset the board
ARM/LPC214X-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_ARM7TDMI=y
CONFIG_ARCH_CHIP - Identifies the arch/*/chip subdirectory
CONFIG_ARCH_CHIP=lpc214x
CONFIG_ARCH_CHIP_name - For use in C code
CONFIG_ARCH_CHIP_LPC214X
CONFIG_ARCH_BOARD - Identifies the configs subdirectory and
hence, the board that supports the particular chip or SoC.
CONFIG_ARCH_BOARD=mcu123-lpc214x
CONFIG_ARCH_BOARD_name - For use in C code
CONFIG_ARCH_BOARD_MCU123 (for the Spectrum Digital C5471 EVM)
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 RAM.
CONFIG_DRAM_START - The start address of installed RAM
CONFIG_DRAM_END - Should be (CONFIG_DRAM_START+CONFIG_DRAM_SIZE)
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_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.
LPC2148 specific chip initialization
These provide register setup values:
CONFIG_EXTMEM_MODE, CONFIG_RAM_MODE, CONFIG_CODE_BASE, CONFIG_PLL_SETUP,
CONFIG_MAM_SETUP, CONFIG_APBDIV_SETUP, CONFIG_EMC_SETUP, CONFIG_BCFG0_SETUP,
CONFIG_BCFG1_SETUP, CONFIG_BCFG2_SETUP, CONFIG_BCFG3_SETUP, CONFIG_ADC_SETUP
CONFIG_LPC214x_FIO - Enable fast GPIO (vs. legacy, "old" GPIO).
LPC214X specific device driver settings
CONFIG_UARTn_SERIAL_CONSOLE - selects the UARTn for the
console and ttys0 (default is the UART0).
CONFIG_UARTn_RXBUFSIZE - Characters are buffered as received.
This specific the size of the receive buffer
CONFIG_UARTn_TXBUFSIZE - Characters are buffered before
being sent. This specific the size of the transmit buffer
CONFIG_UARTn_BAUD - The configure BAUD of the UART.
CONFIG_UARTn_BITS - The number of bits. Must be either 7 or 8.
CONFIG_UARTn_PARTIY - 0=no parity, 1=odd parity, 2=even parity, 3=mark 1, 4=space 0
CONFIG_UARTn_2STOP - Two stop bits
LPC214X USB Configuration
CONFIG_LPC214X_USBDEV_FRAME_INTERRUPT
Handle USB Start-Of-Frame events.
Enable reading SOF from interrupt handler vs. simply reading on demand.
Probably a bad idea... Unless there is some issue with sampling the SOF
from hardware asynchronously.
CONFIG_LPC214X_USBDEV_EPFAST_INTERRUPT
Enable high priority interrupts. I have no idea why you might want to
do that
CONFIG_LPC214X_USBDEV_NDMADESCRIPTORS
Number of DMA descriptors to allocate in the 8Kb USB RAM. This is a
tradeoff between the number of DMA channels that can be supported vs
the size of the DMA buffers available.
CONFIG_LPC214X_USBDEV_DMA
Enable lpc214x-specific DMA support
Configurations
^^^^^^^^^^^^^^
Each NXP LPC214x configuration is maintained in a sudirectory and
can be selected as follow:
cd tools
./configure.sh mcu123-lpc214x/<subdir>
cd -
. ./setenv.sh
Where <subdir> is one of the following:
ostest:
This configuration directory, performs a simple OS test using
examples/ostest.
nsh:
Configures the NuttShell (nsh) located at examples/nsh. The
Configuration enables only the serial NSH interfaces.
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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