README
^^^^^^
README for NuttX port to the Zilogic's ZKIT-ARM-1769 [NXP-LPC1769]
board.
Contents
^^^^^^^^
ZKit-ARM LPC1769 Board
Development Environment
GNU Toolchain Options
NuttX buildroot Toolchain
LEDs
ZKit-ARM Configuration Options
Configurations
Zilogic's ZKit-ARM-1769 Board
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Pin Description On Board Connector
-------------------------------- ---------------- -------------
P0.0/RD1/TXD3/SDA1 RD1 CAN1
P0.1/TD1/RXD3/SCL1 TD1
P0.2/TXD0/AD0.7 TXD0 COM0
P0.3/RXD0/AD0.6 RXD0
P0.4/I2SRX_CLK/RD2/CAP2.0 GPIO0
P0.5/I2SRX_WS/TD2/CAP2.1 GPIO1
P0.6/I2SRX_SDA/SSEL1/MAT2.0 SSEL1 SPI
P0.7/I2STX_CLK/SCK1/MAT2.1 SCK1
P0.8/I2STX_WS/MISO1/MAT2.2 MISO1
P0.9/I2STX_SDA/MOSI1/MAT2.3 MOSI1
P0.10/TXD2/SDA2/MAT3.0 TXD2 COM2
P0.11/RXD2/SCL2/MAT3.1 RXD2
P0.15/TXD1/SCK0/SCK SD-SCK
P0.16/RXD1/SSEL0/SSEL SD-SSEL SD-CARD
P0.17/CTS1/MISO0/MISO SD-MISO
P0.18/DCD1/M0SI0/MOSI SD-MOSI
P0.19/DSR1/SDA1 LED1
P0.20/DTR1/SCL1 DTR1 COM1
P0.21/RI1/RD1 NC LED2
P0.22/RTS1/TD1 RTS1 COM1
P0.23/AD0.0/I2SRX_CLK/CAP3.0 AD0
P0.24/AD0.1/I2SRX_WS/CAP3.1 AD1 AIN
P0.25/AD0.2/I2SRX_SDA/TXD3 AD2
P0.26/AD0.3/AOUT/RXD3 AD3
P0.27/SDA0/USB_SDA SDA0 I2C0
P0.28/SCL0/USB_SCL SCL0
P0.29/USB_D+ USB-D+ USB
P0.30/USB_D- USB-D-
P1.0/ENET_TXD0 ETH-TXD0
P1.1/ENET_TXD1 ETH-TXD1
P1.4/ENET_TX_EN ETH-TXEN
P1.8/ENET_CRS ETH-CRS
P1.9/ENET_RXD0 ETH-RXD0 ETH
P1.10/ENET_RXD1 ETH-RXD1
P1.14/ENET_RX_ER ETH-RXER
P1.15/ENET_REF_CLK ETH-REFCLK
P1.16/ENET_MDC ETH-MDC
P1.17/ENET_MDIO ETH-MDIO
P1.18/USB_UP_LED/PWM1.1/CAP1.0 USB-UP-LED
P1.19/MCOA0/nUSB_PPWR/CAP1.1 KEY1
P1.20/MCFB0/PWM1.2/SCK0 LCD-SCK
P1.21/MCABORT/PWM1.3/SSEL0 LCD-SSEL
P1.22/MCOB0/USB_PWRD/MAT1.0 LCD-A0 LCD
P1.23/MCFB1/PWM1.4/MISO0 NC
P1.24/MCFB2/PWM1.5/MOSI0 LCD_MOSI
P1.25/MCOA1/MAT1.1 LCD-RST
P1.26/MCOB1/PWM1.6/CAP0.0 LCD-AO
P1.27/CLKOUT/nUSB_OVRCR/CAP0.1 KEY2
P1.28/MCOA2/MAT0.0 KEY3
P1.29/MCOB2/PCAP1.1/MAT0.1 CAP1 PWM-CON
P1.30/VBUS/AD0.4 VBUS USB
P1.31/SCK1/AD0.5 KEY4
P2.0/PWM1.1/TXD1 TXD1
P2.1/PWM1.2/RXD1 RXD1 COM1
P2.2/PWM1.3/CTS1/TRACEDATA3 CTS1
P2.3/PWM1.4/DCD1/TRACEDATA2 PWM4
P2.4/PWM1.5/DSR1/TRACEDATA1 PWM5 PWM
P2.5/PWM1.6/DTR1/TRACEDATA0 PWM6
P2.6/PCAP1.0/RI1/TRACECLK CAP0
P2.7/RD2/RTS1 RD2 CAN2
P2.8/TD2/TXD2 TD2
P2.9/USB_CONNECT/RXD2 USB_CONNECT USB
P2.10/nEINT0/NMI ISP
P2.11/nEINT1/I2STX_CLK INT1 I2C
P2.12/nEINT2/I2STX_WS SD-DET SD-CARD
P2.13/nEINT3/I2STX_SDA KEY5
P3.25/MAT0.0/PWM1.2 PWM2 PWM
P3.26/STCLK/MAT0.1/PWM1.3 PWM3
P4.28/RX_MCLK/MAT2.0/TXD3 GPIO2 SPI
P4.28/RX_MCLK/MAT2.0/TXD3 GPIO3
Zilogic's ZKit-ARM-1769 Board
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
SD Slot
-------
Board LPC1768
SD Signal Pin
--- ----------- ----------
CS SD-SSEL P0.16 SSEL0
DIN SD-MOSI P0.18 MOSI0
DOUT SD-MISO P0.17 MISO0
CLK SD-SCK P0.15 SCK0
CD SD-DET P2.12
USB Device
----------
Board LPC1768
Signal Pin
----------------- -----------------
USB_CONNECT P2.9 USB_CONNECT
USB_DM P0.29 USB_D-
USB_DP P0.30 USB_D+
USB_VBUS P1.30 USB_VBUS
USB_UPLED P1.18 USB_UPLED
128x64 LCD with SPI interface
---------------------------------------
The LCD display is connected to the SPI-bus.
ZKit-ARM Signals
----------------------------+--------------- -------------------------------------------
LPC1758 Pin | Board Signal Description
----------------------------+--------------- -------------------------------------------
P1.20/MCFB0/PWM1.2/SCK0 | LCD-SCK LCD Clock signal (D6)
P1.21/MCABORT/PWM1.3/SSEL0 | LCD-SSEL LCD Chip Select (CSB)
P1.22/MCOB0/USB_PWRD/MAT1.0 | LCD-A0 LCD-A0 (A0)
P1.23/MCFB1/PWM1.4/MISO0 | N.C
P1.24/MCFB2/PWM1.5/MOSI0 | LCD-MOSI LCD Data (D7)
P1.25/MCOA1/MAT1.1 | LCD-RST LCD Reset (RSTB) - Resets Everything in LCD
----------------------------+--------------- -------------------------------------------
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 Code Red GNU toolchain
2. The CodeSourcery GNU toolchain,
3. The devkitARM GNU toolchain,
4. The NuttX buildroot Toolchain (see below).
All testing has been conducted using the Code Red toolchain and the
make system is setup to default to use the Code Red Linux toolchain. To use
the other toolchain, you simply need add one of the following configuration
options to your .config (or defconfig) file:
CONFIG_ARMV7M_TOOLCHAIN_CODESOURCERYW=y : CodeSourcery under Windows
CONFIG_ARMV7M_TOOLCHAIN_CODESOURCERYL=y : CodeSourcery under Linux
CONFIG_ARMV7M_TOOLCHAIN_DEVKITARM=y : devkitARM under Windows
CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : NuttX buildroot under Linux or Cygwin (default)
CONFIG_ARMV7M_TOOLCHAIN_CODEREDW=y : Code Red toolchain under Windows
CONFIG_ARMV7M_TOOLCHAIN_CODEREDL=y : Code Red toolchain under Linux
CONFIG_ARMV7M_TOOLCHAIN_ATOLLIC=y : The Atollic toolchain
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 Code Red (for Windoes)
are Windows native toolchains. The CodeSourcey (for Linux), Code Red (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 no 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.
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/projects/nuttx/files/).
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 zkit-arm-1769/<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.
NOTE: The cortexm3-defconfig-4.3.3 produces an older-style is OABI toolchain.
There is another configuration, cortexm3-eabi-defconfig-4.6.3, that will
build a newer, EABI, toolchain. Unfortunately, the 4.6.3 EABI toolchain is
not compatible with the NXFLAT tools. See the top-level TODO file (under
"Binary loaders") for more information about this problem. If you plan to
use NXFLAT, please do not use the GCC 4.6.3 EABI toochain; instead use the
GCC 4.3.3 OABI toolchain.
NXFLAT Toolchain
^^^^^^^^^^^^^^^^
If you are *not* using the NuttX buildroot toolchain and you want to use
the NXFLAT tools, then you will still have to build a portion of the buildroot
tools -- just the NXFLAT tools. The buildroot with the NXFLAT tools can
be downloaded from the NuttX SourceForge download site
(https://sourceforge.net/projects/nuttx/files/).
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 zkit-arm-1769/<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-nxflat .config
6. make oldconfig
7. make
8. Edit setenv.h, if necessary, so that the PATH variable includes
the path to the newly builtNXFLAT binaries.
LEDs
^^^^
If CONFIG_ARCH_LEDS is defined, then support for the ZKit-ARM LEDs will be
included in the build. See:
- configs/zkit-arm-1769/include/board.h - Defines LED constants, types and
prototypes the LED interface functions.
- configs/zkit-arm-1769/src/zkitarm_internal.h - GPIO settings for the LEDs.
- configs/zkit-arm-1769/src/up_leds.c - LED control logic.
The ZKit-ARM LPC1768 has a single LEDs (there are more on the Embedded Artists
base board, but those are not controlled by NuttX). Usage this single LED by NuttX
is as follows:
- The LED is not illuminated until the ZKit-ARM completes initialization.
If the LED is stuck in the OFF state, this means that the ZKit-ARM did not
complete intialization.
- Each time the OS enters an interrupt (or a signal) it will turn the LED OFF and
restores its previous stated upon return from the interrupt (or signal).
The normal state, after initialization will be a dull glow. The brightness of
the glow will be inversely related to the proportion of time spent within interrupt
handling logic. The glow may decrease in brightness when the system is very
busy handling device interrupts and increase in brightness as the system becomes
idle.
Stuck in the OFF state suggests that that the system never completed
initialization; Stuck in the ON state would indicated that the system
intialialized, but is not takint interrupts.
- If a fatal assertion or a fatal unhandled exception occurs, the LED will flash
strongly as a slow, 2Hz rate.
ZKit-ARM Configuration Options
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
General Architecture Settings:
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=lpc17xx
CONFIG_ARCH_CHIP_name - For use in C code to identify the exact
chip:
CONFIG_ARCH_CHIP_LPC1768=y
CONFIG_ARCH_BOARD - Identifies the configs subdirectory and
hence, the board that supports the particular chip or SoC.
CONFIG_ARCH_BOARD=zkit-arm-1769
CONFIG_ARCH_BOARD_name - For use in C code
CONFIG_ARCH_BOARD_ZKITARM=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 (CPU SRAM in this case):
CONFIG_DRAM_SIZE=(32*1024) (32Kb)
There is an additional 32Kb of SRAM in AHB SRAM banks 0 and 1.
CONFIG_DRAM_START - The start address of installed DRAM
CONFIG_DRAM_START=0x10000000
CONFIG_ARCH_IRQPRIO - The LPC17xx 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_LPC17_MAINOSC=y
CONFIG_LPC17_PLL0=y
CONFIG_LPC17_PLL1=n
CONFIG_LPC17_ETHERNET=n
CONFIG_LPC17_USBHOST=n
CONFIG_LPC17_USBOTG=n
CONFIG_LPC17_USBDEV=n
CONFIG_LPC17_UART0=y
CONFIG_LPC17_UART1=n
CONFIG_LPC17_UART2=n
CONFIG_LPC17_UART3=n
CONFIG_LPC17_CAN1=n
CONFIG_LPC17_CAN2=n
CONFIG_LPC17_SPI=n
CONFIG_LPC17_SSP0=n
CONFIG_LPC17_SSP1=n
CONFIG_LPC17_I2C0=n
CONFIG_LPC17_I2C1=n
CONFIG_LPC17_I2S=n
CONFIG_LPC17_TMR0=n
CONFIG_LPC17_TMR1=n
CONFIG_LPC17_TMR2=n
CONFIG_LPC17_TMR3=n
CONFIG_LPC17_RIT=n
CONFIG_LPC17_PWM0=n
CONFIG_LPC17_MCPWM=n
CONFIG_LPC17_QEI=n
CONFIG_LPC17_RTC=n
CONFIG_LPC17_WDT=n
CONFIG_LPC17_ADC=n
CONFIG_LPC17_DAC=n
CONFIG_LPC17_GPDMA=n
CONFIG_LPC17_FLASH=n
LPC17xx 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. Must be
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
CONFIG_UARTn_2STOP - Two stop bits
LPC17xx specific CAN device driver settings. These settings all
require CONFIG_CAN:
CONFIG_CAN_EXTID - Enables support for the 29-bit extended ID. Default
Standard 11-bit IDs.
CONFIG_CAN1_BAUD - CAN1 BAUD rate. Required if CONFIG_LPC17_CAN1 is defined.
CONFIG_CAN2_BAUD - CAN1 BAUD rate. Required if CONFIG_LPC17_CAN2 is defined.
CONFIG_CAN1_DIVISOR - CAN1 is clocked at CCLK divided by this number.
(the CCLK frequency is divided by this number to get the CAN clock).
Options = {1,2,4,6}. Default: 4.
CONFIG_CAN2_DIVISOR - CAN2 is clocked at CCLK divided by this number.
(the CCLK frequency is divided by this number to get the CAN clock).
Options = {1,2,4,6}. Default: 4.
CONFIG_CAN_TSEG1 - The number of CAN time quanta in segment 1. Default: 6
CONFIG_CAN_TSEG2 = the number of CAN time quanta in segment 2. Default: 7
LPC17xx specific PHY/Ethernet device driver settings. These setting
also require CONFIG_NET and CONFIG_LPC17_ETHERNET.
CONFIG_PHY_KS8721 - Selects Micrel KS8721 PHY
CONFIG_PHY_AUTONEG - Enable auto-negotion
CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM. Default: 16Kb
CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
CONFIG_NET_PRIORITY - Ethernet interrupt priority. The is default is
the higest priority.
CONFIG_NET_WOL - Enable Wake-up on Lan (not fully implemented).
CONFIG_NET_REGDEBUG - Enabled low level register debug. Also needs
CONFIG_DEBUG.
CONFIG_NET_DUMPPACKET - Dump all received and transmitted packets.
Also needs CONFIG_DEBUG.
CONFIG_NET_HASH - Enable receipt of near-perfect match frames.
CONFIG_NET_MULTICAST - Enable receipt of multicast (and unicast) frames.
Automatically set if CONFIG_NET_IGMP is selected.
LPC17xx USB Device Configuration
CONFIG_LPC17_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_LPC17_USBDEV_EPFAST_INTERRUPT
Enable high priority interrupts. I have no idea why you might want to
do that
CONFIG_LPC17_USBDEV_NDMADESCRIPTORS
Number of DMA descriptors to allocate in SRAM.
CONFIG_LPC17_USBDEV_DMA
Enable lpc17xx-specific DMA support
CONFIG_LPC17_USBDEV_NOVBUS
Define if the hardware implementation does not support the VBUS signal
CONFIG_LPC17_USBDEV_NOLED
Define if the hardware implementation does not support the LED output
LPC17xx USB Host Configuration (the ZKit-ARM does not support USB Host)
CONFIG_USBHOST_OHCIRAM_SIZE
Total size of OHCI RAM (in AHB SRAM Bank 1)
CONFIG_USBHOST_NEDS
Number of endpoint descriptors
CONFIG_USBHOST_NTDS
Number of transfer descriptors
CONFIG_USBHOST_TDBUFFERS
Number of transfer descriptor buffers
CONFIG_USBHOST_TDBUFSIZE
Size of one transfer descriptor buffer
CONFIG_USBHOST_IOBUFSIZE
Size of one end-user I/O buffer. This can be zero if the
application can guarantee that all end-user I/O buffers
reside in AHB SRAM.
Configurations
^^^^^^^^^^^^^^
Each ZKit-ARM configuration is maintained in a sudirectory and can be
selected as follow:
cd tools
./configure.sh zkit-arm-1769/<subdir>
cd -
. ./setenv.sh
Where <subdir> is one of the following:
hello:
This builds an example application using apps/examples/hello. See
apps/examples/README.txt for information about the examples.
NOTES:
1. This configuration uses the mconf-based configuration tool. To
change this configuration using that tool, you should:
a. Build and install the kconfig-mconf tool. See nuttx/README.txt
and misc/tools/
b. Execute 'make menuconfig' in nuttx/ in order to start the
reconfiguration process.
2. Default toolchain:
CONFIG_HOST_LINUX=y : Builds under Windows (or Cygwin)
CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : NuttX buildroot toolchain
thttpd:
This builds the THTTPD web server example using the THTTPD and
the apps/examples/thttpd application.
NOTES:
1. This configuration uses the mconf-based configuration tool. To
change this configuration using that tool, you should:
a. Build and install the kconfig-mconf tool. See nuttx/README.txt
and misc/tools/
b. Execute 'make menuconfig' in nuttx/ in order to start the
reconfiguration process.
2. Default toolchain:
CONFIG_HOST_LINUX=y : Builds under Windows (or Cygwin)
CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : NuttX buildroot toolchain
3. TCP/IP (only) networking is enabled with this configuration:
CONFIG_EXAMPLES_THTTPD_NOMAC=y : Will use MAC 00:e0:de:ad:be:ef
CONFIG_EXAMPLES_THTTPD_DRIPADDR=0xac100002 : Gateway 172.16.00.02
CONFIG_EXAMPLES_THTTPD_NETMASK=0xffffff00 : Netmask 255.255.255.0
4. You will need to build the NXFLAT toolchain as described above in
order to use this example.
