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)

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.

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 PATH environment variable 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
Bitbucket download site (https://bitbucket.org/nuttx/buildroot/downloads/).
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. Make sure 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 Bitbucket download site
(https://bitbucket.org/nuttx/nuttx/downloads/).

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. Make sure that the PATH variable includes the path to the newly built
NXFLAT 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.

It is also possible to use an external debugger such as the Segger JLink
(EDU or commercial models) provided:

1) The CN4 jumpers are removed to disconnect the on-board STLinkV2 from
the STM32F3.

2) The appropriate (20 pin connector to flying wire) adapter is used to connect
the debugger to the required pins on the expansion headers (see below).

Note that the 1x6 header on the STLinkV2 side of the board labeled "SWD"
is for the STLink micro (STM32F1) and is not connected to the STM32F3.

3) OpenOCD version 0.9.0 or later is used. Earlier versions support either
JTAG only or are buggy for SWD.

The signals used with external (SWD) debugging are:

VREF (3V)
GROUND (GND)
SWCLK (PA14)
SWIO (PA13)
SWO (PB3)
RESET (NRST)

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_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_STM32_CAN_REGDEBUG - If CONFIG_DEBUG_FEATURES 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 -

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
see additional README.txt files in the NuttX tools repository.

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
see additional README.txt files in the NuttX tools repository.

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_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_USBMONITOR=y : Enable the USB monitor daemon
CONFIG_USBMONITOR_STACKSIZE=2048 : USB monitor daemon stack size
CONFIG_USBMONITOR_PRIORITY=50 : USB monitor daemon priority
CONFIG_USBMONITOR_INTERVAL=1 : Dump trace data every second
CONFIG_USBMONITOR_TRACEINIT=y : Enable TRACE output
CONFIG_USBMONITOR_TRACECLASS=y
CONFIG_USBMONITOR_TRACETRANSFERS=y
CONFIG_USBMONITOR_TRACECONTROLLER=y
CONFIG_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