Files
nuttx/configs/lpcxpresso-lpc1768
patacongo 7e6395346b Fix some issues with LPC17xx UART2 and 3 configurations
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3498 42af7a65-404d-4744-a932-0658087f49c3
2011-04-13 14:49:21 +00:00
..
2011-04-12 19:37:33 +00:00
2011-04-13 03:12:51 +00:00

README

^^^^^^



README for NuttX port to the Embedded Artists' LPCXpresso base board with

the LPCXpresso daughter board.



Contents

^^^^^^^^



  LCPXpresso LPC1768 Board

  Development Environment

  GNU Toolchain Options

  NuttX buildroot Toolchain

  Code Red IDE

  LEDs

  LPCXpresso Configuration Options

  Configurations



LCPXpresso LPC1768 Board

^^^^^^^^^^^^^^^^^^^^^^^^



  Pin Description                  Connector On Board       Base Board

  -------------------------------- --------- -------------- ---------------------



  P0[0]/RD1/TXD3/SDA1               J6-9     I2C E2PROM SDA TXD3/SDA1

  P0[1]/TD1/RXD3/SCL                J6-10                   RXD3/SCL1

  P0[2]/TXD0/AD0[7]                 J6-21    

  P0[3]/RXD0/AD0[6]                 J6-22    

  P0[4]/I2SRX-CLK/RD2/CAP2.0        J6-38                   CAN_RX2

  P0[5]/I2SRX-WS/TD2/CAP2.1         J6-39                   CAN_TX2

  P0[6]/I2SRX_SDA/SSEL1/MAT2[0]     J6-8                    SSEL1

  P0[7]/I2STX_CLK/SCK1/MAT2[1]      J6-7                    SCK1

  P0[8]/I2STX_WS/MISO1/MAT2[2]      J6-6                    MISO1

  P0[9]/I2STX_SDA/MOSI1/MAT2[3]     J6-5                    MOSI1

  P0[10]                            J6-40                   TXD2/SDA2

  P0[11]                            J6-41                   RXD2/SCL2

  P0[15]/TXD1/SCK0/SCK              J6-13                   TXD1/SCK0

  P0[16]/RXD1/SSEL0/SSEL            J6-14                   RXD1/SSEL0

  P0[17]/CTS1/MISO0/MISO            J6-12                   MISO0

  P0[18]/DCD1/MOSI0/MOSI            J6-11                   MOSI0

  P0[19]/DSR1/SDA1                  PAD17                   N/A

  P0[20]/DTR1/SCL1                  PAD18    I2C E2PROM SCL N/A

  P0[21]/RI1/MCIPWR/RD1             J6-23                  

  P0[22]/RTS1/TD1                   J6-24    LED            

  P0[23]/AD0[0]/I2SRX_CLK/CAP3[0]   J6-15                   AD0.0

  P0[24]/AD0[1]/I2SRX_WS/CAP3[1]    J6-16                   AD0.1

  P0[25]/AD0[2]/I2SRX_SDA/TXD3      J6-17                   AD0.2

  P0[26]/AD0[3]/AOUT/RXD3           J6-18                   AD0.3/AOUT / RGB LED

  P0[27]/SDA0/USB_SDA               J6-25                   

  P0[28]/SCL0                       J6-26                   

  P0[29]/USB_D+                     J6-37                   USB_D+

  P0[30]/USB_D-                     J6-36                   USB_D-



  P1[0]/ENET-TXD0                   J6-34?  TXD0            TX-(Ethernet PHY)

  P1[1]/ENET_TXD1                   J6-35?  TXD1            TX+(Ethernet PHY)

  P1[4]/ENET_TX_EN                          TXEN            N/A

  P1[8]/ENET_CRS                            CRS_DV/MODE2    N/A

  P1[9]/ENET_RXD0                   J6-32?  RXD0/MODE0      RD-(Ethernet PHY)

  P1[10]/ENET_RXD1                  J6-33?  RXD1/MODE1      RD+(Ethernet PHY)

  P1[14]/ENET_RX_ER                         RXER/PHYAD0     N/A

  P1[15]/ENET_REF_CLK                       REFCLK          N/A

  P1[16]/ENET_MDC                           MDC             N/A

  P1[17]/ENET_MDIO                          MDIO            N/A

  P1[18]/USB_UP_LED/PWM1[1]/CAP1[0] PAD1                    N/A

  P1[19]/MC0A/USB_PPWR/N_CAP1.1     PAD2                    N/A

  P1[20]/MCFB0/PWM1.2/SCK0          PAD3                    N/A

  P1[21]/MCABORT/PWM1.3/SSEL0       PAD4                    N/A

  P1[22]/MC0B/USB-PWRD/MAT1.0       PAD5                    N/A

  P1[23]/MCFB1/PWM1.4/MISO0         PAD6                    N/A

  P1[24]/MCFB2/PWM1.5/MOSI0         PAD7                    N/A

  P1[25]/MC1A/MAT1.1                PAD8                    N/A

  P1[26]/MC1B/PWM1.6/CAP0.0         PAD9                    N/A

  P1[27]/CLKOUT/USB-OVRCR-N/CAP0.1  PAD10                   N/A

  P1[28]/MC2A/PCAP1.0/MAT0.0        PAD11                   N/A

  P1[29]/MC2B/PCAP1.1/MAT0.1        PAD12                   N/A

  P1[30]/VBUS/AD0[4]                J6-19                   AD0.4

  P1[31]/SCK1/AD0[5]                J6-20                   AD0.5



  P2[0]/PWM1.1/TXD1                 J6-42                   PWM1.1 / RGB LED / RS422 RX

  P2[1]/PWM1.2/RXD1                 J6-43                   PWM1.2 / OLED voltage / RGB LED

  P2[2]/PWM1.3/CTS1/TRACEDATA[3]    J6-44                   PWM1.3

  P2[3]/PWM1.4/DCD1/TRACEDATA[2]    J6-45                   PWM1.4

  P2[4]/PWM1.5/DSR1/TRACEDATA[1]    J6-46                   PWM1.5

  P2[5]/PWM1[6]/DTR1/TRACEDATA[0]   J6-47                   PWM1.6

  P2[6]/PCAP1[0]/RI1/TRACECLK       J6-48    

  P2[7]/RD2/RTS1                    J6-49    

  P2[8]/TD2/TXD2                    J6-50    

  P2[9]/USB_CONNECT/RXD2            PAD19   USB Pullup      N/A

  P2[10]/EINT0/NMI                  J6-51    

  P2[11]/EINT1/I2STX_CLK            J6-52    

  P2[12]/EINT2/I2STX_WS             j6-53    

  P2[13]/EINT3/I2STX_SDA            J6-27                 



  P3[25]/MAT0.0/PWM1.2              PAD13                   N/A

  P3[26]/STCLK/MAT0.1/PWM1.3        PAD14                   N/A



  P4[28]/RX-MCLK/MAT2.0/TXD3        PAD15                   N/A

  P4[29]/TX-MCLK/MAT2.1/RXD3        PAD16                   N/A



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,

  3. 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 or devkitARM toolchain, you simply need add one of the

  following configuration options to your .config (or defconfig) file:



    CONFIG_LPC17_CODESOURCERYW=y   : CodeSourcery under Windows

    CONFIG_LPC17_CODESOURCERYL=y   : CodeSourcery under Linux

    CONFIG_LPC17_DEVKITARM=y       : devkitARM under Windows

    CONFIG_LPC17_BUILDROOT=y       : NuttX buildroot under Linux or Cygwin (default)



  If you are not using CONFIG_LPC17_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)and devkitARM 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.



Code Red IDE

^^^^^^^^^^^^



  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).

  

  Makefile Build

  --------------

  Under Eclipse, it is pretty easy to set up an "empty makefile project" and

  simply use the NuttX makefile to build the system.  That is almost for free

  under Linux.  Under Windows, you will need to set up the "Cygwin GCC" empty

  makefile project in order to work with Windows (Google for "Eclipse Cygwin" -

  there is a lot of help on the internet).



  Native Build

  ------------

  Here are a few tips 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/lpc17xx,

     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/lpc17x/lpc17_vectors.S.



  Using Code Red GNU Tools from Cygwin

  ------------------------------------



  Under Cygwin, the Code Red command line tools (e.g., arm-non-eabi-gcc) cannot

  be executed because the they only have execut privileges for Administrators.  I

  worked around this by:

  

  Opening a native Cygwin RXVT as Administrator (Right click, "Run as administrator"),

  then executing 'chmod 755 *.exe' in the following directories:



  /cygdrive/c/nxp/lpcxpreeso_3.6/bin, and

  /cygdrive/c/nxp/lpcxpreeso_3.6/Tools/bin



  Command Line Flash Programming

  ------------------------------



  If using LPCLink as your debug connection, first of all boot the LPC-Link using

  the script:



    bin\Scripts\bootLPCXpresso type



  where type = winusb for Windows XP, or type = hid for Windows Vista / 7.



  Now run the flash programming utility with the following options



    flash_utility wire -ptarget -flash-load[-exec]=filename [-load-base=base_address]



  Where flash_utility is one of:



    crt_emu_lpc11_13 (for LPC11xx or LPC13xx parts)

    crt_emu_cm3_nxp (for LPC17xx parts)

    crt_emu_a7_nxp (for LPC21/22/23/24 parts)

    crt_emu_a9_nxp (for LPC31/32 and LPC29xx parts)

    crt_emu_cm3_lmi (for TI Stellaris LM3S parts



  wire is one of:



    (empty) (for Red Probe+, Red Probe, RDB1768v1, or TI Stellaris evaluation boards)

    -wire=hid (for RDB1768v2 without upgraded firmware)

    -wire=winusb (for RDB1768v2 with upgraded firmware)

    -wire=winusb (for LPC-Link on Windows XP)

    -wire=hid (for LPC-Link on Windows Vista/ Windows 7)



  target is the target chip name. For example LPC1343, LPC1114/301, LPC1768 etc.



  filename is the file to flash program. It may be an executable (axf) or a binary

  (bin) file. If using a binary file, the base_address must be specified.



  base_address is the base load address when flash programming a binary file. It

  should be specified as a hex value with a leading 0x.



  Note:

  - flash-load will leave the processor in a stopped state

  - flash-load-exec will start execution of application as soon as download has

    completed.



  Examples

    To load the executable file app.axf and start it executing on an LPC1758

	target using Red Probe, use the following command line:



      crt_emu_cm3_nxp -pLPC1758 -flash-load-exec=app.axf



    To load the binary file binary.bin to address 0x1000 to an LPC1343 target

	using LPC-Link on Windows XP, use the following command line:



      crt_emu_lpc11_13_nxp -wire=hid -pLPC1343 -flash-load=binary.bin -load-base=0x1000



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 lpcxpresso-lpc1768/<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: This is an OABI toolchain.



LEDs

^^^^



  If CONFIG_ARCH_LEDS is defined, then support for the LPCXpresso LEDs will be

  included in the build.  See:



  - configs/lpcxpresso-lpc1768/include/board.h - Defines LED constants, types and

    prototypes the LED interface functions.



  - configs/lpcxpresso-lpc1768/src/lpcxpresso_internal.h - GPIO settings for the LEDs.



  - configs/lpcxpresso-lpc1768/src/up_leds.c - LED control logic.



  The LPCXpresso 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 LPCXpresso completes initialization.

  

    If the LED is stuck in the OFF state, this means that the LPCXpresso 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, 1Hz rate.



LPCXpresso 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=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=lpcxpresso-lpc1768



	CONFIG_ARCH_BOARD_name - For use in C code



	   CONFIG_ARCH_BOARD_LPCEXPRESSO=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_DRAM_END - Last address+1 of installed RAM



	   CONFIG_DRAM_END=(CONFIG_DRAM_START+CONFIG_DRAM_SIZE)



	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_PWM=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 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



  LPC17xx USB Host Configuration (the LPCXpresso 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 LPCXpresso configuration is maintained in a sudirectory and can be

selected as follow:



	cd tools

	./configure.sh lpcxpresso-lpc1768/<subdir>

	cd -

	. ./setenv.sh



Where <subdir> is one of the following:



  ostest:

    This configuration directory, performs a simple OS test using

    examples/ostest.