README
======
This README discusses issues unique to NuttX configurations for the
STMicro STM32F3Discovery development board.
Contents
========
- LEDs
- Serial Console
- FPU
- Debugging
- STM32F3Discovery-specific Configuration Options
- Configurations
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. Non-Lazy Floating Point Register Save
In this configuration floating point register save and restore is
implemented on interrupt entry and return, respectively. In this
case, you may use floating point operations for interrupt handling
logic if necessary. This FPU behavior logic is enabled by default
with:
CONFIG_ARCH_FPU=y
2. Lazy Floating Point Register Save.
An alternative implementation only 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
CONFIG_ARMV7M_LAZYFPU=y
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
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)
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 boards/ 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.
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_STM32_CAN1_BAUD - CAN1 BAUD rate. Required if CONFIG_STM32_CAN1
is defined.
CONFIG_STM32_CAN2_BAUD - CAN1 BAUD rate. Required if CONFIG_STM32_CAN2
is defined.
CONFIG_STM32_CAN_TSEG1 - The number of CAN time quanta in segment 1.
Default: 6
CONFIG_STM32_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:
tools/configure.sh STM32F3Discovery:<subdir>
Where <subdir> 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 ARM EABI 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_GNU_EABIW=y : GNU EABI toolchain 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 following 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 ARM EABI 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_GNU_EABIW=y : GNU EABI toolchain 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 SYSLOG 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 logging device (USART2 in this
configuration):
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
