README ^^^^^^ This README discusses issues unique to NuttX configurations for the Atmel SAM4L Xplained Pro development board. This board features the ATSAM4LC4C MCU Contents ^^^^^^^^ - Development Environment - GNU Toolchain Options - IDEs - NuttX EABI "buildroot" Toolchain - NuttX OABI "buildroot" Toolchain - NXFLAT Toolchain - LEDs - Virtual COM Port - SAM4L Xplained Pro-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_SAM34_CODESOURCERYW=y : CodeSourcery under Windows CONFIG_SAM34_CODESOURCERYL=y : CodeSourcery under Linux CONFIG_SAM34_DEVKITARM=y : devkitARM under Windows CONFIG_SAM34_BUILDROOT=y : NuttX buildroot under Linux or Cygwin (default) If you are not using CONFIG_SAM34_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 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. MKDEP = $(TOPDIR)/tools/mknulldeps.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). 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/sam34, arch/arm/src/common, arch/arm/src/armv7-m, 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/sam34/sam_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 EABI "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/buildroot/). This GNU toolchain builds and executes in the Linux or Cygwin environment. 1. You must have already configured Nuttx in /nuttx. cd tools ./configure.shsam4l-xplained/ 2. Download the latest buildroot package into 3. unpack the buildroot tarball. The resulting directory may have versioning information on it like buildroot-x.y.z. If so, rename /buildroot-x.y.z to /buildroot. 4. cd /buildroot 5. cp configs/cortexm3-eabi-defconfig-4.6.3 .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 details PLUS some special instructions that you will need to follow if you are building a Cortex-M3 toolchain for Cygwin under Windows. NOTE: Unfortunately, the 4.6.3 EABI toolchain is not compatible with the 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. See instructions below. NuttX OABI "buildroot" Toolchain ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The older, OABI buildroot toolchain is also available. To use the OABI toolchain: 1. When building the buildroot toolchain, either (1) modify the cortexm3-eabi-defconfig-4.6.3 configuration to use EABI (using 'make menuconfig'), or (2) use an exising OABI configuration such as cortexm3-defconfig-4.3.3 2. Modify the Make.defs file to use the OABI conventions: +CROSSDEV = arm-nuttx-elf- +ARCHCPUFLAGS = -mtune=cortex-m3 -march=armv7-m -mfloat-abi=soft +NXFLATLDFLAGS2 = $(NXFLATLDFLAGS1) -T$(TOPDIR)/binfmt/libnxflat/gnu-nxflat-gotoff.ld -no-check-sections -CROSSDEV = arm-nuttx-eabi- -ARCHCPUFLAGS = -mcpu=cortex-m3 -mthumb -mfloat-abi=soft -NXFLATLDFLAGS2 = $(NXFLATLDFLAGS1) -T$(TOPDIR)/binfmt/libnxflat/gnu-nxflat-pcrel.ld -no-check-sections 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 /nuttx. cd tools ./configure.sh lpcxpresso-lpc1768/ 2. Download the latest buildroot package into 3. unpack the buildroot tarball. The resulting directory may have versioning information on it like buildroot-x.y.z. If so, rename /buildroot-x.y.z to /buildroot. 4. cd /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 ^^^^ There are three LEDs on board the SAM4L Xplained Pro board: The EDBG controls two of the LEDs, a power LED and a status LED. There is only one user controllable LED, a yellow LED labeled LED0 near the SAM4L USB connector. This LED is controlled by PC07 and LED0 can be activated by driving the PC07 to GND. When CONFIG_ARCH_LEDS is defined in the NuttX configuration, NuttX will control LED0 as follows: SYMBOL Meaning LED0 ------------------- ----------------------- ------ LED_STARTED NuttX has been started OFF LED_HEAPALLOCATE Heap has been allocated OFF LED_IRQSENABLED Interrupts enabled OFF LED_STACKCREATED Idle stack created ON LED_INIRQ In an interrupt N/C LED_SIGNAL In a signal handler N/C LED_ASSERTION An assertion failed N/C LED_PANIC The system has crashed FLASH Thus is LED0 is statically on, NuttX has successfully booted and is, apparently, running normmally. If LED0 is flashing at approximately 2Hz, then a fatal error has been detected and the system has halted. Virtual COM Port ^^^^^^^^^^^^^^^^ The SAM4L Xplained Pro contains an Embedded Debugger (EDBG) that can be used to program and debug the ATSAM4LC4C using Serial Wire Debug (SWD). The Embedded debugger also include a Virtual Com port interface over USART1. Virtual COM port connections: PC26 USART1 RXD PC27 USART1 TXD SAM4L Xplained Pro-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="sam34" CONFIG_ARCH_CHIP_name - For use in C code to identify the exact chip: CONFIG_ARCH_CHIP_SAM34 CONFIG_ARCH_CHIP_SAM3U 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=sam4l-xplained (for the SAM4L Xplained Pro development board) CONFIG_ARCH_BOARD_name - For use in C code CONFIG_ARCH_BOARD_SAM4L_XPLAINED=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_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_SAM34_DMA CONFIG_SAM34_HSMCI CONFIG_SAM34_NAND CONFIG_SAM34_SPI CONFIG_SAM34_UART CONFIG_SAM34_USART0 CONFIG_SAM34_USART1 CONFIG_SAM34_USART2 CONFIG_SAM34_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 LCD Options. Other than the standard LCD configuration options (see configs/README.txt), the SAM4L Xplained Pro driver also supports: CONFIG_LCD_PORTRAIT - Present the display in the standard 240x320 "Portrait" orientation. Default: The display is rotated to support a 320x240 "Landscape" orientation. Configurations ^^^^^^^^^^^^^^ Each SAM4L Xplained Pro configuration is maintained in a sub-directory and can be selected as follow: cd tools ./configure.shsam4l-xplained/ cd - . ./setenv.sh Before sourcing the setenv.sh file above, you should examine it and perform edits as necessary so that BUILDROOT_BIN is the correct path to the directory than holds your toolchain binaries. And then build NuttX by simply typing the following. At the conclusion of the make, the nuttx binary will reside in an ELF file called, simply, nuttx. make The that is provided above as an argument to the tools/configure.sh must be is one of the following: ostest: This configuration directory, performs a simple OS test using examples/ostest.