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README ^^^^^^ This README discusses issues unique to NuttX configurations for the Arduino DUE board featuring the Atmel ATSAM3X8E MCU running at 84 MHz. Contents ^^^^^^^^ - PIO Pin Usage - Development Environment - GNU Toolchain Options - IDEs - NuttX EABI "buildroot" Toolchain - NuttX OABI "buildroot" Toolchain - NXFLAT Toolchain - Buttons and LEDs - Serial Consoles - SAM4S Xplained-specific Configuration Options - Configurations PIO Pin Usage ^^^^^^^^^^^^^ PORTA PORTB PORTC ------------------------------ ------------------------------ -------------------------------- PIO SIGNAL CONN PIN PIO SIGNAL CONN PIN PIO SIGNAL CONN PIN ----- ---------- ---- -------- ----- ------------ ---- ------ ----- ----------- ---- --------- PA0 CANTX0 ADCH 8 PB0 ETX_CLK ETH 1 PC0 ERASE N/A PA1 CANRX0 ACDH 7 PB1 ETX_EN ETH 3 PC1 PIN33 XIO 14 PA2 AD7 ADCL 7 PB2 ETXD0 ETH 5 PC2 PIN34 XIO 15 PA3 AD6 ADCL 6 PB3 ETXD1 ETH 7 PC3 PIN35 XIO 16 PA4 AD5 ADCL 5 PB4 ERX_DV ETH 10 PC4 PIN36 XIO 17 PA5 EEXTINT ETH 8 PB5 ERXD0 ETH 9 PC5 PIN37 XIO 18 PA6 AD4 ADCL 4 PB6 ERXD1 ETH 11 PC6 PIN38 XIO 19 PA7 PIN31 XIO 12 PB7 ERX_ER ETH 13 PC7 PIN39 XIO 20 PA8 [U]RX PWML 1 PB8 EMDC ETH 14 PC8 PIN40 XIO 21 PA9 [U]TX PWML 2 PB9 EMDIO ETH 12 PC9 PIN41 XIO 22 PA10 RXD2 COMM 6 PB10 UOTGVBOF Vbus power PC10 N/C N/A PA11 TXD2 COMM 5 PB11 UOTGID USB1 4 PC11 N/C N/A PA12 RXD1 COMM 4 PB12 SDA0-3 COMM 7 PC12 PIN51 XIO 32 PA13 TXD1 COMM 3 PB13 SCL0-3 COMM 8 PC13 PIN50 XIO 31 PA14 PIN23 XIO 4 PB14 CANTX1/IO XIO 34 PC14 PIN49 XIO 30 PA15 PIN24 XIO 5 PB15 DAC0(CANRX1) ADCH 5 PC15 PIN48 XIO 29 PA16 AD0 ADCL 0 PB16 DAC1 ADCH 6 PC16 PIN47 XIO 28 PA17 SDA1 PWMH 9 PB17 AD8 ADCH 1 PC17 PIN46 XIO 27 PA18 SCL1 PWMH 10 PB18 AD9 ADCH 2 PC18 PIN45 XIO 26 PA19 PIN42 XIO 23 PB19 AD10 ADCH 3 PC19 PIN44 XIO 25 PA20 PIN43 XIO 24 PB20 AD11(TXD3) ADCH 4 PC20 N/C N/A PA21 TXL TX YELLOW LED PB21 AD14(RXD3) XIO 33 PC21 PWM9 PWMH 2 PA22 AD3 ADCL 3 PB22 N/C N/A PC22 PWM8 PWMH 1 PA23 AD2 ADCL 2 PB23 SS3 ??? PC23 PWM7 PWML 8 PA24 AD1 ADCL 1 PB24 N/C N/A PC24 PWM6 PWML 7 PA25 MISO SPI 1 PB25 PWM2 PWML 3 PC25 PWM5 PWML 6 PA26 MOSI SPI 4 PB26 PIN22 ??? PC26 SS1/PWM4 ??? (there are two) PA27 SPCK SPI 3 PB27 PWM13 PWMH 6 PC27 N/C N/A PA28 SS0/PWM10 (ETH) PB28 JTAG_TCK JTAG 4 PC28 PWM3 PWML 4 PA29 SS1/PWM4 (SD) PB29 JTAG_TDI JTAG 8 PC29 SS0/PWM10 ??? (there are two) PA30 N/A N/A PB30 JTAG_TDO JTAG 6 PC30 RXL RX YELLOW LED PA31 N/A N/A PB31 JTAG_TMS JTAG 2 PC31 N/A N/A ----- ---------- ---- -------- ----- ------------ ---- ------ ----- ----------- ---- --------- PORTA PORTB PORTC ------------------------------ ------------------------------ -------------------------------- PIO SIGNAL CONN PIN PIO SIGNAL CONN PIN PIO SIGNAL CONN PIN ----- ---------- ---- -------- ----- ------------ ---- ------ ----- ----------- ---- --------- PA0 PIN25 XIO 6 PE0 N/A N/A PF0 N/A N/A PD1 PIN26 XIO 7 PE1 N/A N/A PF1 N/A N/A PD2 PIN27 XIO 8 PE2 N/A N/A PF2 N/A N/A PD3 PIN28 XIO 9 PE3 N/A N/A PF3 N/A N/A PD4 TXD0 COMM 1 PE4 N/A N/A PF4 N/A N/A PD5 RXD0 COMM 2 PE5 N/A N/A PF5 N/A N/A PD6 PIN29 XIO 10 PE6 N/A N/A PF6 N/A N/A PD7 PWM11 PWMH 4 PE7 N/A N/A PF7 N/A N/A PD8 PWM12 PWMH 5 PE8 N/A N/A PF8 N/A N/A PD9 PIN30 XIO 11 PE9 N/A N/A PF9 N/A N/A PD10 PIN32 XIO 13 PE10 N/A N/A PF10 N/A N/A PD11 N/A N/A PE11 N/A N/A PF11 N/A N/A PD12 N/A N/A PE12 N/A N/A PF12 N/A N/A PD13 N/A N/A PE13 N/A N/A PF13 N/A N/A PD14 N/A N/A PE14 N/A N/A PF14 N/A N/A PD15 N/A N/A PE15 N/A N/A PF15 N/A N/A PD16 N/A N/A PE16 N/A N/A PF16 N/A N/A PD17 N/A N/A PE17 N/A N/A PF17 N/A N/A PD18 N/A N/A PE18 N/A N/A PF18 N/A N/A PD19 N/A N/A PE19 N/A N/A PF19 N/A N/A PD20 N/A N/A PE20 N/A N/A PF20 N/A N/A PD21 N/A N/A PE21 N/A N/A PF21 N/A N/A PD22 N/A N/A PE22 N/A N/A PF22 N/A N/A PD23 N/A N/A PE23 N/A N/A PF23 N/A N/A PD24 N/A N/A PE24 N/A N/A PF24 N/A N/A PD25 N/A N/A PE25 N/A N/A PF25 N/A N/A PD26 N/A N/A PE26 N/A N/A PF26 N/A N/A PD27 N/A N/A PE27 N/A N/A PF27 N/A N/A PD28 N/A N/A PE28 N/A N/A PF28 N/A N/A PD29 N/A N/A PE29 N/A N/A PF29 N/A N/A PD30 N/A N/A PE30 N/A N/A PF30 N/A N/A PD31 N/A5 N/A PE31 N/A N/A PF31 N/A 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, 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_ARMV7M_TOOLCHAIN_CODESOURCERYW=y : CodeSourcery under Windows CONFIG_ARMV7M_TOOLCHAIN_CODESOURCERYL=y : CodeSourcery under Linux CONFIG_ARMV7M_TOOLCHAIN_ATOLLIC=y : Atollic toolchain for Windos CONFIG_ARMV7M_TOOLCHAIN_DEVKITARM=y : devkitARM under Windows CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : NuttX buildroot under Linux or Cygwin (default) CONFIG_ARMV7M_TOOLCHAIN_GNU_EABIL=y : Generic GCC ARM EABI toolchain for Linux CONFIG_ARMV7M_TOOLCHAIN_GNU_EABIW=y : Generic GCC ARM EABI toolchain for Windows If you are not using CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT, then you may also have to modify the PATH in the setenv.h file if your make cannot find the tools. NOTE about Windows native toolchains ------------------------------------ The CodeSourcery (for Windows), Atollic, and devkitARM toolchains are Windows native toolchains. The CodeSourcery (for Linux), NuttX buildroot, and, perhaps, the generic GCC 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 <some-dir>/nuttx. cd tools ./configure.shsam4s-xplained/<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-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 <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-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. Buttons and LEDs ^^^^^^^^^^^^^^^^ Buttons ------- There are no buttons on the Arduino Due board. LEDs ---- There are two user-controllable LEDs on board the Arduino Due board: LED GPIO ---------------- ----- TX Yellow LED PA21 RX Yellow LED PC30 Both are pulled high and can be illuminated by driving the corresponding GPIO output to low. These LEDs are not used by the board port unless CONFIG_ARCH_LEDS is defined. In that case, the usage by the board port is defined in include/board.h and src/sam_leds.c. The LEDs are used to encode OS-related events as follows: SYMBOL Meaning LED state RX TX ------------------- ----------------------- -------- -------- LED_STARTED NuttX has been started OFF OFF LED_HEAPALLOCATE Heap has been allocated OFF OFF LED_IRQSENABLED Interrupts enabled OFF OFF LED_STACKCREATED Idle stack created ON OFF LED_INIRQ In an interrupt No change LED_SIGNAL In a signal handler No change LED_ASSERTION An assertion failed No change LED_PANIC The system has crashed OFF Blinking LED_IDLE MCU is is sleep mode Not used Thus if RX is statically on, NuttX has successfully booted and is, apparently, running normmally. If TX is flashing at approximately 2Hz, then a fatal error has been detected and the system has halted. Serial Consoles ^^^^^^^^^^^^^^^ Any of UART and USART0-3 may be used as a serial console. By default, the UART is used as the serial console in all configurations. But that is easily changed by modifying the configuration as described under "Configurations" below. ------------------------------ PIO SIGNAL CONN PIN ----- ---------- ---- -------- PA8 [U]RX PWML 1 PA9 [U]TX PWML 2 PD4 TXD0 COMM 1 PD5 RXD0 COMM 2 PA12 RXD1 COMM 4 PA13 TXD1 COMM 3 PA10 RXD2 COMM 6 PA11 TXD2 COMM 5 PB20 AD11(TXD3) ADCH 4 PB21 AD14(RXD3) XIO 33 The outputs from these pins is 3.3V. You will need to connect RS232 transceiver to get the signals to RS232 levels (or connect the pins to the USB virual COM port. Arduino DUE-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_SAM3X CONFIG_ARCH_CHIP_ATSAM3X8E CONFIG_ARCH_BOARD - Identifies the configs subdirectory and hence, the board that supports the particular chip or SoC. CONFIG_ARCH_BOARD=arduino-due (for the Arduino Due development board) CONFIG_ARCH_BOARD_name - For use in C code CONFIG_ARCH_BOARD_ARDUINO_DUE=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=0x00008000 (32Kb) 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_RTC - Real Time Clock CONFIG_SAM34_RTT - Real Time Timer CONFIG_SAM34_WDT - Watchdog Timer CONFIG_SAM34_UART0 - UART 0 CONFIG_SAM34_SMC - Static Memory Controller CONFIG_SAM34_SDRAMC - SDRAM Controller CONFIG_SAM34_USART0 - USART 0 CONFIG_SAM34_USART1 - USART 1 CONFIG_SAM34_USART2 - USART 2 CONFIG_SAM34_USART3 - USART 3 CONFIG_SAM34_HSMCI - High Speed Multimedia Card Interface CONFIG_SAM34_TWI0 - Two-Wire Interface 0 (master/slave) CONFIG_SAM34_TWI1 - Two-Wire Interface 1 (master/slave) CONFIG_SAM34_SPI0 - Serial Peripheral Interface 0 CONFIG_SAM34_SPI1 - Serial Peripheral Interface 1 CONFIG_SAM34_SSC - Synchronous Serial Controller CONFIG_SAM34_TC0 - Timer Counter 0 CONFIG_SAM34_TC1 - Timer Counter 1 CONFIG_SAM34_TC2 - Timer Counter 2 CONFIG_SAM34_TC3 - Timer Counter 3 CONFIG_SAM34_TC4 - Timer Counter 4 CONFIG_SAM34_TC5 - Timer Counter 5 CONFIG_SAM34_TC6 - Timer Counter 6 CONFIG_SAM34_TC7 - Timer Counter 7 CONFIG_SAM34_TC8 - Timer Counter 8 CONFIG_SAM34_PWM - Pulse Width Modulation CONFIG_SAM34_ADC12B - 12-bit Analog To Digital Converter CONFIG_SAM34_DACC - Digital To Analog Converter CONFIG_SAM34_DMA - DMA Controller CONFIG_SAM34_UOTGHS - USB OTG High Speed CONFIG_SAM34_TRNG - True Random Number Generator CONFIG_SAM34_EMAC - Ethernet MAC CONFIG_SAM34_CAN0 - CAN Controller 0 CONFIG_SAM34_CAN1 - CAN Controller 1 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_GPIOD_IRQ CONFIG_GPIOE_IRQ CONFIG_GPIOF_IRQ CONFIG_USART0_ISUART CONFIG_USART1_ISUART CONFIG_USART2_ISUART CONFIG_USART3_ISUART ST91SAM4S 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 Configurations ^^^^^^^^^^^^^^ Each SAM4S Xplained configuration is maintained in a sub-directory and can be selected as follow: cd tools ./configure.sh arduino-due/<subdir> 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 <subdir> that is provided above as an argument to the tools/configure.sh must be is one of the following. NOTES: 1. These configurations use the mconf-based configuration tool. To change any of these configurations 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. Unless stated otherwise, all configurations generate console output on UART1 which is available on J1 or J4 (see the section "Serial Consoles" above). USART1 or the virtual COM port on UART0 are options. The virtual COM port could be used, for example, by reconfiguring to use UART0 like: System Type -> AT91SAM3/4 Peripheral Support CONFIG_SAM_UART0=y CONFIG_SAM_UART1=n Device Drivers -> Serial Driver Support -> Serial Console CONFIG_UART0_SERIAL_CONSOLE=y Device Drivers -> Serial Driver Support -> UART0 Configuration CONFIG_UART0_2STOP=0 CONFIG_UART0_BAUD=115200 CONFIG_UART0_BITS=8 CONFIG_UART0_PARITY=0 CONFIG_UART0_RXBUFSIZE=256 CONFIG_UART0_TXBUFSIZE=256 3. Unless otherwise stated, the configurations are setup for Linux (or any other POSIX environment like Cygwin under Windows): Build Setup: CONFIG_HOST_LINUX=y : Linux or other POSIX environment 4. These configurations use the older, OABI, buildroot toolchain. But that is easily reconfigured: System Type -> Toolchain: CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : Buildroot toolchain CONFIG_ARMV7M_OABI_TOOLCHAIN=y : Older, OABI toolchain If you want to use the Atmel GCC toolchain, here are the steps to do so: Build Setup: CONFIG_HOST_WINDOWS=y : Windows CONFIG_HOST_CYGWIN=y : Using Cygwin or other POSIX environment System Type -> Toolchain: CONFIG_ARMV7M_TOOLCHAIN_GNU_EABIW=y : General GCC EABI toolchain under windows This re-configuration should be done before making NuttX or else the subsequent 'make' will fail. If you have already attempted building NuttX then you will have to 1) 'make distclean' to remove the old configuration, 2) 'cd tools; ./configure.sh sam3u-ek/ksnh' to start with a fresh configuration, and 3) perform the configuration changes above. Also, make sure that your PATH variable has the new path to your Atmel tools. Try 'which arm-none-eabi-gcc' to make sure that you are selecting the right tool. setenv.sh is available for you to use to set or PATH variable. The path in the that file may not, however, be correct for your installation. See also the "NOTE about Windows native toolchains" in the section call "GNU Toolchain Options" above. Configuration sub-directories ----------------------------- ostest: This configuration directory performs a simple OS test using examples/ostest. See NOTES above. nsh: This configuration directory will built the NuttShell. See NOTES above. NOTES: 1. The configuration configuration can be modified to include support for the on-board SRAM (1MB). System Type -> External Memory Configuration CONFIG_ARCH_EXTSRAM0=y : Select SRAM on CS0 CONFIG_ARCH_EXTSRAM0SIZE=1048576 : Size=1MB Now what are you going to do with the SRAM. There are two choices: a) To enable the NuttX RAM test that may be used to verify the external SRAM: System Type -> External Memory Configuration CONFIG_ARCH_EXTSRAM0HEAP=n : Don't add to heap Application Configuration -> System NSH Add-Ons CONFIG_SYSTEM_RAMTEST=y : Enable the RAM test built-in In this configuration, the SDRAM is not added to heap and so is not excessible to the applications. So the RAM test can be freely executed against the SRAM memory beginning at address 0x6000:0000 (CS0). nsh> ramtest -h Usage: <noname> [-w|h|b] <hex-address> <decimal-size> Where: <hex-address> starting address of the test. <decimal-size> number of memory locations (in bytes). -w Sets the width of a memory location to 32-bits. -h Sets the width of a memory location to 16-bits (default). -b Sets the width of a memory location to 8-bits. To test the entire external SRAM: nsh> ramtest 60000000 1048576 RAMTest: Marching ones: 60000000 1048576 RAMTest: Marching zeroes: 60000000 1048576 RAMTest: Pattern test: 60000000 1048576 55555555 aaaaaaaa RAMTest: Pattern test: 60000000 1048576 66666666 99999999 RAMTest: Pattern test: 60000000 1048576 33333333 cccccccc RAMTest: Address-in-address test: 60000000 1048576 b) To add this RAM to the NuttX heap, you would need to change the configuration as follows: System Type -> External Memory Configuration CONFIG_ARCH_EXTSRAM0HEAP=y : Add external RAM to heap Memory Management -CONFIG_MM_REGIONS=1 : Only the internal SRAM +CONFIG_MM_REGIONS=2 : Also include external SRAM