README ====== This README discusses issues unique to NuttX configurations for the HY-MiniSTM32V development board. Contents ======== - Development Environment - GNU Toolchain Options - IDEs - NuttX EABI "buildroot" Toolchain - NuttX OABI "buildroot" Toolchain - NXFLAT Toolchain - ST Bootloader - LEDs - RTC - HY-Mini 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, 3. Raisonance GNU toolchain, or 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_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 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: 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. 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. You many have to build NuttX one time from the Cygwin command line in order to obtain the pre-built startup object needed by an IDE. 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 hymini-stm32v/ 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 hymini-stm32v/ 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. ST Bootloader ============= A bootloader code is available in an internal boot ROM memory (called 'system memory' in STM documentation) in all STM32 MCUs. For the F103xx this bootloader can be used to upload & flash a firmware image through the USART1. Notes: - The bootloader is activated by the BOOT0 / BOOT1 pins after a MCU reset. See STM application note 2606 for more details. - On the hymini-stm32 board the USART1 is connected to a PL2303 USB<->serial converter. To enter bootloader mode in the hymini-stm32 board: - Press the 'boot0' button (located next to 'reset' button) - While boot0 button is pressed, reset the board through the reset button. - Once you pressed / released the 'reset' button, the MCU has (re)started in bootloader mode (and you can then release the boot0 button). A flash utility must be used on your development workstation to upload / flash a firmware image. (The 'stm32flash' open source tool, available at http://stm32flash.googlecode.com/ has been used sucessfully). LEDs ==== The HY-MiniSTM32 board provides only two controlable LEDs labeled LED1 and LED2. Usage of these LEDs is defined in include/board.h and src/up_leds.c. They are encoded as follows: SYMBOL Meaning LED1* LED2 ------------------- ----------------------- ------- ------- LED_STARTED NuttX has been started OFF OFF LED_HEAPALLOCATE Heap has been allocated ON OFF LED_IRQSENABLED Interrupts enabled OFF ON LED_STACKCREATED Idle stack created ON OFF LED_INIRQ In an interrupt** OFF N/C LED_SIGNAL In a signal handler*** N/C ON LED_ASSERTION An assertion failed ON ON LED_PANIC The system has crashed BLINK BLINK LED_IDLE STM32 is is sleep mode (Optional, not used) * If Nuttx starts correctly, normal state is to have LED1 on and LED2 off. ** LED1 is turned off during interrupt. *** LED2 is turned on during signal handler. RTC === The STM32 RTC may configured using the following settings. CONFIG_RTC - Enables general support for a hardware RTC. Specific architectures may require other specific settings. CONFIG_RTC_HIRES - The typical RTC keeps time to resolution of 1 second, usually supporting a 32-bit time_t value. In this case, the RTC is used to "seed" the normal NuttX timer and the NuttX timer provides for higher resoution time. If CONFIG_RTC_HIRES is enabled in the NuttX configuration, then the RTC provides higher resolution time and completely replaces the system timer for purpose of date and time. CONFIG_RTC_FREQUENCY - If CONFIG_RTC_HIRES is defined, then the frequency of the high resolution RTC must be provided. If CONFIG_RTC_HIRES is not defined, CONFIG_RTC_FREQUENCY is assumed to be one. CONFIG_RTC_ALARM - Enable if the RTC hardware supports setting of an alarm. A callback function will be executed when the alarm goes off In hi-res mode, the STM32 RTC operates only at 16384Hz. Overflow interrupts are handled when the 32-bit RTC counter overflows every 3 days and 43 minutes. A BKP register is incremented on each overflow interrupt creating, effectively, a 48-bit RTC counter. In the lo-res mode, the RTC operates at 1Hz. Overflow interrupts are not handled (because the next overflow is not expected until the year 2106. WARNING: Overflow interrupts are lost whenever the STM32 is powered down. The overflow interrupt may be lost even if the STM32 is powered down only momentarily. Therefore hi-res solution is only useful in systems where the power is always on. HY-Mini 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=stm32 CONFIG_ARCH_CHIP_name - For use in C code to identify the exact chip: CONFIG_ARCH_CHIP_STM32F103VC 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=hymini-stm32v (for the HY-Mini development board) CONFIG_ARCH_BOARD_name - For use in C code CONFIG_ARCH_BOARD_HYMINI_STM32V=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=0x0000C000 (48Kb) CONFIG_RAM_START - The start address of installed DRAM CONFIG_RAM_START=0x20000000 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: AHB --- CONFIG_STM32_DMA1 CONFIG_STM32_DMA2 CONFIG_STM32_CRC CONFIG_STM32_FSMC CONFIG_STM32_SDIO APB1 ---- CONFIG_STM32_TIM2 CONFIG_STM32_TIM3 (required for PWM control of LCD backlight) CONFIG_STM32_TIM4 CONFIG_STM32_TIM5 CONFIG_STM32_TIM6 CONFIG_STM32_TIM7 CONFIG_STM32_IWDG CONFIG_STM32_WWDG CONFIG_STM32_IWDG CONFIG_STM32_SPI2 CONFIG_STM32_SPI4 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_BKP CONFIG_STM32_PWR CONFIG_STM32_DAC CONFIG_STM32_USB APB2 ---- CONFIG_STM32_ADC1 CONFIG_STM32_ADC2 CONFIG_STM32_TIM1 CONFIG_STM32_SPI1 CONFIG_STM32_TIM8 CONFIG_STM32_USART1 CONFIG_STM32_ADC3 Timer and I2C devices may need to the following to force power to be applied unconditionally at power up. (Otherwise, the device is powered when it is initialized). CONFIG_STM32_FORCEPOWER The Timer3 alternate mapping is required for PWM control of LCD backlight CONFIG_STM32_TIM3_PARTIAL_REMAP=y 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,..,8 CONFIG_STM32_TIMn_ADC Reserve timer n for use by ADC, n=1,..,8 CONFIG_STM32_TIMn_ADCm Reserve timer n to trigger ADCm, n=1,..,8, m=1,..,3 CONFIG_STM32_TIMn_DAC Reserve timer n for use by DAC, n=1,..,8 CONFIG_STM32_TIMn_DACm Reserve timer n to trigger DACm, n=1,..,8, m=1,..,2 Others alternate pin mappings available: CONFIG_STM32_TIM1_FULL_REMAP CONFIG_STM32_TIM1_PARTIAL_REMAP CONFIG_STM32_TIM2_FULL_REMAP CONFIG_STM32_TIM2_PARTIAL_REMAP_1 CONFIG_STM32_TIM2_PARTIAL_REMAP_2 CONFIG_STM32_TIM3_FULL_REMAP CONFIG_STM32_TIM3_PARTIAL_REMAP CONFIG_STM32_TIM4_REMAP CONFIG_STM32_USART1_REMAP CONFIG_STM32_USART2_REMAP CONFIG_STM32_USART3_FULL_REMAP CONFIG_STM32_USART3_PARTIAL_REMAP CONFIG_STM32_SPI1_REMAP CONFIG_STM32_SPI3_REMAP CONFIG_STM32_I2C1_REMAP CONFIG_STM32_CAN1_REMAP1 CONFIG_STM32_CAN1_REMAP2 CONFIG_STM32_CAN2_REMAP STM32F103V 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). Note: USART1 is connected to a PL2303 serial to USB converter. So USART1 is available through USB port labeled CN3 on the board. 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 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. CONFIG_SDIO_DMA - Support DMA data transfers. Requires CONFIG_STM32_SDIO and CONFIG_STM32_DMA2. CONFIG_SDIO_PRI - Select SDIO interrupt prority. Default: 128 CONFIG_SDIO_DMAPRIO - Select SDIO DMA interrupt priority. Default: Medium CONFIG_SDIO_WIDTH_D1_ONLY - Select 1-bit transfer mode. Default: 4-bit transfer mode. CONFIG_MMCSD_HAVECARDDETECT - Select if SDIO driver card detection is 100% accurate (it is on the HY-MiniSTM32V) HY-MiniSTM32V 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. HY-MiniSTM32V LCD Hardware Configuration. The HY-Mini board may be delivered with either an SSD1289 or an R61505U LCD controller. CONFIG_LCD_R61505U - Selects the R61505U LCD controller. CONFIG_LCD_SSD1289 - Selects the SSD1289 LCD controller. The following options apply for either LCD controller: CONFIG_NX_LCDDRIVER - To be defined to include LCD driver CONFIG_LCD_LANDSCAPE - Define for 320x240 display "landscape" support. In this orientation, the HY-MiniSTM32V's LCD used connector is at the right of the display. Default is this 320x240 "landscape" orientation CONFIG_LCD_PORTRAIT - Define for 240x320 display "portrait" orientation support. In this orientation, the HY-MiniSTM32V's LCD used connector is at the bottom of the display. Default is 320x240 "landscape" orientation. CONFIG_LCD_RPORTRAIT - Define for 240x320 display "reverse portrait" orientation support. In this orientation, the HY-MiniSTM32V's LCD used connector is at the top of the display. Default is 320x240 "landscape" orientation. CONFIG_LCD_BACKLIGHT - Define to support an adjustable backlight using timer 3. The granularity of the settings is determined by CONFIG_LCD_MAXPOWER. Requires CONFIG_STM32_TIM3. Configurations ============== NOTES: - All configurations described below are using the mconf-based configuration tool. To change their 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. - All configurations use a generic GNU EABI toolchain for Linux by default. - They are all configured to generate a binary image that can be flashed through the STM32 internal bootloader. Each HY-MiniSTM32V configuration is maintained in a sub-directory and can be selected as follow: cd tools ./configure.sh hymini-stm32v/ cd - . ./setenv.sh Where is one of the following: buttons: -------- Uses apps/examples/buttons to exercise HY-MiniSTM32V buttons and button interrupts. CONFIG_ARMV7M_TOOLCHAIN_GNU_EABIL=y : Generic GNU EABI toolchain nsh and nsh2: ------------ Configure the NuttShell (nsh) located at examples/nsh. Differences between the two NSH configurations: =========== ======================= ================================ nsh nsh2 =========== ======================= ================================ Serial Debug output: USART1 Debug output: USART1 Console: NSH output: USART1 NSH output: USART1 (2) ----------- ----------------------- -------------------------------- microSD Yes (5) Yes (5) Support ----------- ----------------------- -------------------------------- FAT FS CONFIG_FAT_LCNAMES=y CONFIG_FAT_LCNAMES=y Config CONFIG_FAT_LFN=n CONFIG_FAT_LFN=y (3) ----------- ----------------------- -------------------------------- LCD Driver No Yes Support ----------- ----------------------- -------------------------------- RTC Support No Yes ----------- ----------------------- -------------------------------- Support for No Yes Built-in Apps ----------- ----------------------- -------------------------------- Built-in None apps/examples/nx Apps apps/examples/nxhello apps/system/usbmsc (4) apps/examples/buttons apps/examples/nximage =========== ======================= ================================ (1) You will probably need to modify nsh/setenv.sh or nsh2/setenv.sh to set up the correct PATH variable for whichever toolchain you may use. (2) When any other device other than /dev/console is used for a user interface, (1) linefeeds (\n) will not be expanded to carriage return / linefeeds \r\n). You will need to configure your terminal program to account for this. And (2) input is not automatically echoed so you will have to turn local echo on. (3) Microsoft holds several patents related to the design of long file names in the FAT file system. Please refer to the details in the top-level COPYING file. Please do not use FAT long file name unless you are familiar with these patent issues. (4) When built as an NSH add-on command (CONFIG_NSH_BUILTIN_APPS=y), Caution should be used to assure that the SD drive is not in use when the USB storage device is configured. Specifically, the SD driver should be unmounted like: nsh> mount -t vfat /dev/mmcsd0 /mnt/sdcard # Card is mounted in NSH ... nsh> umount /mnd/sdcard # Unmount before connecting USB!!! nsh> msconn # Connect the USB storage device ... nsh> msdis # Disconnect USB storate device nsh> mount -t vfat /dev/mmcsd0 /mnt/sdcard # Restore the mount Failure to do this could result in corruption of the SD card format. (5) Option CONFIG_NSH_ARCHINIT must be enabled in order to call the SDIO slot initialization code. usbmsc: ------- This configuration directory exercises the USB mass storage class driver at system/usbmsc. See examples/README.txt for more information. 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. NOTES: 1. This configuration does have UART2 output enabled and set up as the system logging device: 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" : UART2 will be /dev/ttyS0 However, there is nothing to generate SYLOG output in the default configuration so nothing should appear on UART2 unless you enable some debug output or enable the USB monitor. 2. 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 (UART2 in this configuraion): CONFIG_USBDEV_TRACE=y : Enable USB trace feature CONFIG_USBDEV_TRACE_NRECORDS=128 : Buffer 128 records in memory CONFIG_NSH_USBDEV_TRACE=n : No builtin tracing from NSH CONFIG_NSH_ARCHINIT=y : Automatically start the USB monitor 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=2 : Dump trace data every 2 seconds 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 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: CONFIG_CDCACM=y : Disable the CDC/ACM serial device class CONFIG_CDCACM_CONSOLE=y : 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 usbserial: --------- This configuration directory exercises the USB serial class driver at examples/usbserial. See examples/README.txt for more information. CONFIG_HOST_LINUX=y : Linux host CONFIG_ARMV7M_TOOLCHAIN_CODESOURCERYL=y : CodeSourcery toolchain under Linux USB debug output can be enabled as by changing the following settings in the configuration file: -CONFIG_DEBUG=n -CONFIG_DEBUG_VERBOSE=n -CONFIG_DEBUG_USB=n +CONFIG_DEBUG=y +CONFIG_DEBUG_VERBOSE=y +CONFIG_DEBUG_USB=y -CONFIG_EXAMPLES_USBSERIAL_TRACEINIT=n -CONFIG_EXAMPLES_USBSERIAL_TRACECLASS=n -CONFIG_EXAMPLES_USBSERIAL_TRACETRANSFERS=n -CONFIG_EXAMPLES_USBSERIAL_TRACECONTROLLER=n -CONFIG_EXAMPLES_USBSERIAL_TRACEINTERRUPTS=n +CONFIG_EXAMPLES_USBSERIAL_TRACEINIT=y +CONFIG_EXAMPLES_USBSERIAL_TRACECLASS=y +CONFIG_EXAMPLES_USBSERIAL_TRACETRANSFERS=y +CONFIG_EXAMPLES_USBSERIAL_TRACECONTROLLER=y +CONFIG_EXAMPLES_USBSERIAL_TRACEINTERRUPTS=y By default, the usbserial example uses the Prolific PL2303 serial/USB converter emulation. The example can be modified serial/USB converter emulation. The example can be modified to use the CDC/ACM serial class by making the following changes to the configuration file: -CONFIG_PL2303=y +CONFIG_PL2303=n -CONFIG_CDCACM=n +CONFIG_CDCACM=y The example can also be converted to use the alternative USB serial example at apps/examples/usbterm by changing the following: -CONFIG_EXAMPLES_USBSERIAL=y +CONFIG_EXAMPLES_USBSERIAL=n -CONFIG_EXAMPLES_USBTERM=n +CONFIG_EXAMPLES_USBTERM=y