README ====== This README discusses issues unique to NuttX configurations for the STMicro STM32F3Discovery development board. Contents ======== - Development Environment - GNU Toolchain Options - IDEs - NuttX EABI "buildroot" Toolchain - NuttX OABI "buildroot" Toolchain - NXFLAT Toolchain - LEDs - Serial Console - FPU - Debugging - STM32F3Discovery-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. GNU Toolchain Options ===================== Toolchain Configurations ------------------------ The NuttX make system has been modified to support the following different toolchain options. 1. The CodeSourcery GNU toolchain, 2. The Atollic Toolchain, 3. The devkitARM GNU toolchain, 4. Raisonance GNU toolchain, or 5. The NuttX buildroot Toolchain (see below). All testing has been conducted using the CodeSourcery toolchain for Windows. To use the Atollic, devkitARM, Raisonance GNU, or NuttX buildroot 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 : The Atollic toolchain under Windows CONFIG_ARMV7M_TOOLCHAIN_DEVKITARM=y : devkitARM under Windows CONFIG_ARMV7M_TOOLCHAIN_RAISONANCE=y : Raisonance RIDE7 under Windows CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : NuttX buildroot under Linux or Cygwin (default) If you change the default toolchain, 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), Atollic, 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 The CodeSourcery Toolchain (2009q1) ----------------------------------- 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. The Atollic "Pro" and "Lite" Toolchain -------------------------------------- One problem that I had with the Atollic toolchains is that the provide a gcc.exe and g++.exe in the same bin/ file as their ARM binaries. If the Atollic bin/ path appears in your PATH variable before /usr/bin, then you will get the wrong gcc when you try to build host executables. This will cause to strange, uninterpretable errors build some host binaries in tools/ when you first make. Also, the Atollic toolchains are the only toolchains that have built-in support for the FPU in these configurations. If you plan to use the Cortex-M4 FPU, you will need to use the Atollic toolchain for now. See the FPU section below for more information. The Atollic "Lite" Toolchain ---------------------------- The free, "Lite" version of the Atollic toolchain does not support C++ nor does it support ar, nm, objdump, or objdcopy. If you use the Atollic "Lite" toolchain, you will have to set: CONFIG_HAVE_CXX=n In order to compile successfully. Otherwise, you will get errors like: "C++ Compiler only available in TrueSTUDIO Professional" The make may then fail in some of the post link processing because of some of the other missing tools. The Make.defs file replaces the ar and nm with the default system x86 tool versions and these seem to work okay. Disable all of the following to avoid using objcopy: CONFIG_RRLOAD_BINARY=n CONFIG_INTELHEX_BINARY=n CONFIG_MOTOROLA_SREC=n CONFIG_RAW_BINARY=n devkitARM --------- The devkitARM toolchain includes a version of MSYS make. Make sure that the 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. 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/stm32, 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/stm32/stm32_vectors.S. With RIDE, I have 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.sh STM32F3Discovery/ 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 ==== The STM32F3Discovery board has ten LEDs. Two of these are controlled by logic on the board and are not available for software control: LD1 PWR: red LED indicates that the board is powered. LD2 COM: LD2 default status is red. LD2 turns to green to indicate that communications are in progress between the PC and the ST-LINK/V2. And eight can be controlled by software: User LD3: red LED is a user LED connected to the I/O PE9 of the STM32F303VCT6. User LD4: blue LED is a user LED connected to the I/O PE8 of the STM32F303VCT6. User LD5: orange LED is a user LED connected to the I/O PE10 of the STM32F303VCT6. User LD6: green LED is a user LED connected to the I/O PE15 of the STM32F303VCT6. User LD7: green LED is a user LED connected to the I/O PE11 of the STM32F303VCT6. User LD8: orange LED is a user LED connected to the I/O PE14 of the STM32F303VCT6. User LD9: blue LED is a user LED connected to the I/O PE12 of the STM32F303VCT6. User LD10: red LED is a user LED connected to the I/O PE13 of the STM32F303VCT6. 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/up_leds.c. The LEDs are used to encode OS-related events as follows: SYMBOL Meaning LED state Initially all LEDs are OFF ------------------- ----------------------- ------------- ------------ LED_STARTED NuttX has been started LD3 ON LED_HEAPALLOCATE Heap has been allocated LD4 ON LED_IRQSENABLED Interrupts enabled LD4 ON LED_STACKCREATED Idle stack created LD6 ON LED_INIRQ In an interrupt LD7 should glow LED_SIGNAL In a signal handler LD8 might glow LED_ASSERTION An assertion failed LD9 ON while handling the assertion LED_PANIC The system has crashed LD10 Blinking at 2Hz LED_IDLE STM32 is is sleep mode (Optional, not used) Serial Console ============== The STM32F3Discovery has no on-board RS-232 driver, however USART2 is configuration as the serial console in all configurations that use a serial console. There are many options for USART2 RX and TX pins. They configured to use PA2 (TX) and PA3 (RX) for connection to an external serial device because of the following settings in the include/board.h file: #define GPIO_USART2_RX GPIO_USART2_RX_2 #define GPIO_USART2_TX GPIO_USART2_TX_2 This can be found on the board at: TX, PA2, Connector P1, pin 14 RX, PA3, Connector P1, pin 11 FPU === FPU Configuration Options ------------------------- There are two version of the FPU support built into the STM32 port. 1. Lazy Floating Point Register Save. This is an untested implementation that saves and restores FPU registers only on context switches. This means: (1) floating point registers are not stored on each context switch and, hence, possibly better interrupt performance. But, (2) since floating point registers are not saved, you cannot use floating point operations within interrupt handlers. This logic can be enabled by simply adding the following to your .config file: CONFIG_ARCH_FPU=y 2. Non-Lazy Floating Point Register Save Mike Smith has contributed an extensive re-write of the ARMv7-M exception handling logic. This includes verified support for the FPU. These changes have not yet been incorporated into the mainline and are still considered experimental. These FPU logic can be enabled with: CONFIG_ARCH_FPU=y CONFIG_ARMV7M_CMNVECTOR=y You will probably also changes to the ld.script in if this option is selected. This should work: -ENTRY(_stext) +ENTRY(__start) /* Treat __start as the anchor for dead code stripping */ +EXTERN(_vectors) /* Force the vectors to be included in the output */ CFLAGS ------ Only recent GCC toolchains have built-in support for the Cortex-M4 FPU. You will see the following lines in each Make.defs file: ifeq ($(CONFIG_ARCH_FPU),y) ARCHCPUFLAGS = -mcpu=cortex-m4 -mthumb -march=armv7e-m -mfpu=fpv4-sp-d16 -mfloat-abi=hard else ARCHCPUFLAGS = -mcpu=cortex-m3 -mthumb -mfloat-abi=soft endif Configuration Changes --------------------- Below are all of the configuration changes that I had to make to configs/stm3240g-eval/nsh2 in order to successfully build NuttX using the Atollic toolchain WITH FPU support: -CONFIG_ARCH_FPU=n : Enable FPU support +CONFIG_ARCH_FPU=y -CONFIG_ARMV7M_TOOLCHAIN_CODESOURCERYW=y : Disable the CodeSourcery toolchain +CONFIG_ARMV7M_TOOLCHAIN_CODESOURCERYW=n -CONFIG_ARMV7M_TOOLCHAIN_ATOLLIC=n : Enable the Atollic toolchain +CONFIG_ARMV7M_TOOLCHAIN_ATOLLIC=y : -CONFIG_INTELHEX_BINARY=y : Suppress generation FLASH download formats +CONFIG_INTELHEX_BINARY=n : (Only necessary with the "Lite" version) -CONFIG_HAVE_CXX=y : Suppress generation of C++ code +CONFIG_HAVE_CXX=n : (Only necessary with the "Lite" version) See the section above on Toolchains, NOTE 2, for explanations for some of the configuration settings. Some of the usual settings are just not supported by the "Lite" version of the Atollic toolchain. Debugging ========= STM32 ST-LINK Utility --------------------- For simply writing to FLASH, I use the STM32 ST-LINK Utility. At least version 2.4.0 is required (older versions do not recognize the STM32 F3 device). This utility is available from free from the STMicro website. Debugging --------- If you are going to use a debugger, you should make sure that the following settings are selection in your configuration file: CONFIG_DEBUG_SYMBOLS=y : Enable debug symbols in the build CONFIG_ARMV7M_USEBASEPRI=y : Use the BASEPRI register to disable interrupts OpenOCD ------- I am told that OpenOCD will work with the ST-Link, but I have never tried it. https://github.com/texane/stlink -------------------------------- This is an open source server for the ST-Link that I have never used. Atollic GDB Server ------------------ You can use the Atollic IDE, but I have never done that either. STM32F3Discovery-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_CORTEXM4=y CONFIG_ARCH_CHIP - Identifies the arch/*/chip subdirectory CONFIG_ARCH_CHIP=stm32 CONFIG_ARCH_CHIP_name - For use in C code to identify the exact chip: CONFIG_ARCH_CHIP_STM32F303VC=y CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG - Enables special STM32 clock configuration features. CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG=n CONFIG_ARCH_BOARD - Identifies the configs subdirectory and hence, the board that supports the particular chip or SoC. CONFIG_ARCH_BOARD=STM32F3Discovery (for the STM32F3Discovery development board) CONFIG_ARCH_BOARD_name - For use in C code CONFIG_ARCH_BOARD_STM32F3_DISCOVERY=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_RAM_SIZE - Describes the installed DRAM (SRAM in this case): CONFIG_RAM_SIZE=0x00010000 (64Kb) CONFIG_RAM_START - The start address of installed DRAM CONFIG_RAM_START=0x20000000 CONFIG_STM32_CCMEXCLUDE - Exclude CCM SRAM from the HEAP CONFIG_ARCH_IRQPRIO - The STM32F3Discovery supports interrupt prioritization CONFIG_ARCH_IRQPRIO=y CONFIG_ARCH_FPU - The STM32F3Discovery supports a floating point unit (FPU) CONFIG_ARCH_FPU=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: AHB1 ---- CONFIG_STM32_DMA1 CONFIG_STM32_DMA2 CONFIG_STM32_CRC CONFIG_STM32_TSC AHB2 ---- (GPIOs are always enabled) AHB3 ---- CONFIG_STM32_ADC1 CONFIG_STM32_ADC2 CONFIG_STM32_ADC3 CONFIG_STM32_ADC4 APB1 ---- CONFIG_STM32_TIM2 CONFIG_STM32_TIM3 CONFIG_STM32_TIM4 CONFIG_STM32_TIM6 CONFIG_STM32_TIM7 CONFIG_STM32_WWDG CONFIG_STM32_IWDG CONFIG_STM32_SPI2 CONFIG_STM32_SPI3 CONFIG_STM32_USART2 CONFIG_STM32_USART3 CONFIG_STM32_UART4 CONFIG_STM32_UART5 CONFIG_STM32_I2C1 CONFIG_STM32_I2C2 CONFIG_STM32_USB CONFIG_STM32_CAN1 CONFIG_STM32_PWR -- Required for RTC CONFIG_STM32_DAC1 APB2 ---- CONFIG_STM32_SYSCFG CONFIG_STM32_TIM1 CONFIG_STM32_SPI1 CONFIG_STM32_TIM8 CONFIG_STM32_USART1 CONFIG_STM32_TIM15 CONFIG_STM32_TIM16 CONFIG_STM32_TIM17 Timer devices may be used for different purposes. One special purpose is to generate modulated outputs for such things as motor control. If CONFIG_STM32_TIMn is defined (as above) then the following may also be defined to indicate that the timer is intended to be used for pulsed output modulation, ADC conversion, or DAC conversion. Note that ADC/DAC require two definition: Not only do you have to assign the timer (n) for used by the ADC or DAC, but then you also have to configure which ADC or DAC (m) it is assigned to. CONFIG_STM32_TIMn_PWM Reserve timer n for use by PWM, n=1,..,14 CONFIG_STM32_TIMn_ADC Reserve timer n for use by ADC, n=1,..,14 CONFIG_STM32_TIMn_ADCm Reserve timer n to trigger ADCm, n=1,..,14, m=1,..,3 CONFIG_STM32_TIMn_DAC Reserve timer n for use by DAC, n=1,..,14 CONFIG_STM32_TIMn_DACm Reserve timer n to trigger DACm, n=1,..,14, m=1,..,2 For each timer that is enabled for PWM usage, we need the following additional configuration settings: CONFIG_STM32_TIMx_CHANNEL - Specifies the timer output channel {1,..,4} NOTE: The STM32 timers are each capable of generating different signals on each of the four channels with different duty cycles. That capability is not supported by this driver: Only one output channel per timer. JTAG Enable settings (by default only SW-DP is enabled): CONFIG_STM32_JTAG_FULL_ENABLE - Enables full SWJ (JTAG-DP + SW-DP) CONFIG_STM32_JTAG_NOJNTRST_ENABLE - Enables full SWJ (JTAG-DP + SW-DP) but without JNTRST. CONFIG_STM32_JTAG_SW_ENABLE - Set JTAG-DP disabled and SW-DP enabled STM32F3Discovery specific device driver settings CONFIG_U[S]ARTn_SERIAL_CONSOLE - selects the USARTn (n=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 STM32F3Discovery CAN Configuration CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or CONFIG_STM32_CAN2 must also be defined) CONFIG_CAN_EXTID - Enables support for the 29-bit extended ID. Default Standard 11-bit IDs. CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages. Default: 8 CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests. Default: 4 CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback mode for testing. The STM32 CAN driver does support loopback mode. CONFIG_CAN1_BAUD - CAN1 BAUD rate. Required if CONFIG_STM32_CAN1 is defined. CONFIG_CAN2_BAUD - CAN1 BAUD rate. Required if CONFIG_STM32_CAN2 is defined. 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 CONFIG_CAN_REGDEBUG - If CONFIG_DEBUG is set, this will generate an dump of all CAN registers. STM32F3Discovery SPI Configuration CONFIG_STM32_SPI_INTERRUPTS - Select to enable interrupt driven SPI support. Non-interrupt-driven, poll-waiting is recommended if the interrupt rate would be to high in the interrupt driven case. CONFIG_STM32_SPI_DMA - Use DMA to improve SPI transfer performance. Cannot be used with CONFIG_STM32_SPI_INTERRUPT. Configurations ============== Each STM32F3Discovery configuration is maintained in a sub-directory and can be selected as follow: cd tools ./configure.sh STM32F3Discovery/ cd - . ./setenv.sh If this is a Windows native build, then configure.bat should be used instead of configure.sh: configure.bat STM32F3Discovery\ Where is one of the following: nsh: --- Configures the NuttShell (nsh) located at apps/examples/nsh. The Configuration enables the serial interfaces on USART2. Support for builtin applications is enabled, but in the base configuration no builtin applications are selected (see NOTES below). 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. By default, this configuration uses the CodeSourcery toolchain for Windows and builds under Cygwin (or probably MSYS). That can easily be reconfigured, of course. CONFIG_HOST_WINDOWS=y : Builds under Windows CONFIG_WINDOWS_CYGWIN=y : Using Cygwin CONFIG_ARMV7M_TOOLCHAIN_CODESOURCERYW=y : CodeSourcery for Windows 3. This configuration includes USB Support (CDC/ACM device) CONFIG_STM32_USB=y : STM32 USB device support CONFIG_USBDEV=y : USB device support must be enabled CONFIG_CDCACM=y : The CDC/ACM driver must be built CONFIG_NSH_BUILTIN_APPS=y : NSH built-in application support must be enabled CONFIG_NSH_ARCHINIT=y : To perform USB initialization The CDC/ACM example is included as two NSH "built-in" commands.\ CONFIG_SYSTEM_CDCACM=y : Enable apps/system/cdcacm The two commands are: sercon : Connect the serial device a create /dev/ttyACM0 serdis : Disconnect the serial device. NOTE: The serial connections/disconnections do not work as advertised. This is because the STM32F3Discovery board does not provide circuitry for control of the "soft connect" USB pullup. As a result, the host PC does not know the USB has been logically connected or disconnected. You have to follow these steps to use USB: 1) Start NSH with USB disconnected 2) enter to 'sercon' command to start the CDC/ACM device, then 3) Connect the USB device to the host. and to close the connection: 4) Disconnect the USB device from the host 5) Enter the 'serdis' command 4. This example can support the watchdog timer test (apps/examples/watchdog) but this must be enabled by selecting: CONFIG_EXAMPLES_WATCHDOG=y : Enable the apps/examples/watchdog CONFIG_WATCHDOG=y : Enables watchdog timer driver support CONFIG_STM32_WWDG=y : Enables the WWDG timer facility, OR CONFIG_STM32_IWDG=y : Enables the IWDG timer facility (but not both) The WWDG watchdog is driven off the (fast) 42MHz PCLK1 and, as result, has a maximum timeout value of 49 milliseconds. for WWDG watchdog, you should also add the fillowing to the configuration file: CONFIG_EXAMPLES_WATCHDOG_PINGDELAY=20 CONFIG_EXAMPLES_WATCHDOG_TIMEOUT=49 The IWDG timer has a range of about 35 seconds and should not be an issue. usbnsh: ------- This is another NSH example. If differs from other 'nsh' configurations in that this configurations uses a USB serial device for console I/O. Such a configuration is useful on the stm32f3discovery which has no builtin RS-232 drivers. Status: As of this writing, this configuration has not ran properly. There appears to be some kind of driver-related issue. 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. By default, this configuration uses the CodeSourcery toolchain for Windows and builds under Cygwin (or probably MSYS). That can easily be reconfigured, of course. Build Setup: CONFIG_HOST_WINDOWS=y : Builds under Windows CONFIG_WINDOWS_CYGWIN=y : Using Cygwin System Type: CONFIG_ARMV7M_TOOLCHAIN_CODESOURCERYW=y : CodeSourcery for Windows 3. This configuration does have USART2 output enabled and set up as the system logging device: Device Drivers -> System Logging Device Options: CONFIG_SYSLOG=y : Enable output to syslog, not console CONFIG_SYSLOG_CHAR=y : Use a character device for system logging CONFIG_SYSLOG_DEVPATH="/dev/ttyS0" : USART2 will be /dev/ttyS0 However, there is nothing to generate SYLOG output in the default configuration so nothing should appear on USART2 unless you enable some debug output or enable the USB monitor. NOTE: Using the SYSLOG to get debug output has limitations. Among those are that you cannot get debug output from interrupt handlers. So, in particularly, debug output is not a useful way to debug the USB device controller driver. Instead, use the USB monitor with USB debug off and USB trance on (see below). 4. Enabling USB monitor SYSLOG output. If tracing is enabled, the USB device will save encoded trace output in in-memory buffer; if the USB monitor is enabled, that trace buffer will be periodically emptied and dumped to the system loggin device (USART2 in this configuraion): Device Drivers -> "USB Device Driver Support: CONFIG_USBDEV_TRACE=y : Enable USB trace feature CONFIG_USBDEV_TRACE_NRECORDS=256 : Buffer 128 records in memory Application Configuration -> NSH LIbrary: CONFIG_NSH_USBDEV_TRACE=n : No builtin tracing from NSH CONFIG_NSH_ARCHINIT=y : Automatically start the USB monitor Application Configuration -> System NSH Add-Ons: CONFIG_SYSTEM_USBMONITOR=y : Enable the USB monitor daemon CONFIG_SYSTEM_USBMONITOR_STACKSIZE=2048 : USB monitor daemon stack size CONFIG_SYSTEM_USBMONITOR_PRIORITY=50 : USB monitor daemon priority CONFIG_SYSTEM_USBMONITOR_INTERVAL=1 : Dump trace data every second CONFIG_SYSTEM_USBMONITOR_TRACEINIT=y : Enable TRACE output CONFIG_SYSTEM_USBMONITOR_TRACECLASS=y CONFIG_SYSTEM_USBMONITOR_TRACETRANSFERS=y CONFIG_SYSTEM_USBMONITOR_TRACECONTROLLER=y CONFIG_SYSTEM_USBMONITOR_TRACEINTERRUPTS=y NOTE: USB debug output also be enabled in this case. Both will appear on the serial SYSLOG output. However, the debug output will be asynchronous with the trace output and, hence, difficult to interpret. 5. The STM32F3Discovery board does not provide circuitry for control of the "soft connect" USB pullup. As a result, the host PC does not know the USB has been logically connected or disconnected. You have to follow these steps to use USB: 1) Start NSH with USB disconnected, then 2) Connect the USB device to the host. 6. Using the Prolifics PL2303 Emulation You could also use the non-standard PL2303 serial device instead of the standard CDC/ACM serial device by changing: Drivers->USB Device Driver Support CONFIG_CDCACM=n : Disable the CDC/ACM serial device class CONFIG_CDCACM_CONSOLE=n : The CDC/ACM serial device is NOT the console CONFIG_PL2303=y : The Prolifics PL2303 emulation is enabled CONFIG_PL2303_CONSOLE=y : The PL2303 serial device is the console