ST Nucleo F401RE

This page discusses issues unique to NuttX configurations for the ST NucleoF401RE boards from ST Micro. See

NucleoF401RE:

  • Microprocessor: 32-bit ARM Cortex M4 at 84MHz STM32F104RE

  • Memory: 512 KB Flash and 96 KB SRAM

  • ADC: 1×12-bit, 2.4 MSPS A/D converter: up to 10 channels

  • DMA: 16-stream DMA controllers with FIFOs and burst support

  • Timers: Up to 11 timers: up to six 16-bit, two 32-bit timers, two watchdog timers, and a SysTick timer

  • GPIO: Up to 81 I/O ports with interrupt capability

  • I2C: Up to 3 × I2C interfaces

  • USARTs: Up to 3 USARTs

  • SPIs: Up to 4 SPIs (2 I2S)

  • SDIO interface

  • USB: USB 2.0 full-speed device/host/OTG controller with on-chip PHY

  • CRC calculation unit

  • RTC

Board features, however, are identical:

  • Peripherals: 1 led, 1 push button

  • Debug: Serial wire debug and JTAG interfaces

  • Expansion I/F Ardino and Morpho Headers

Uses a STM32F103 to provide a ST-Link for programming, debug similar to the OpenOcd FTDI function - USB to JTAG front-end.

See http://mbed.org/platforms/ST-Nucleo-F401RE for more information about these boards.

mbed

The Nucleo-F401RE includes boot loader from mbed:

Using the mbed loader:

  1. Connect the Nucleo-F401RE to the host PC using the USB connector.

  2. A new file system will appear called NUCLEO; open it with Windows Explorer (assuming that you are using Windows).

  3. Drag and drop nuttx.bin into the MBED window. This will load the nuttx.bin binary into the Nucleo-F401RE. The NUCLEO window will close then re-open and the Nucleo-F401RE will be running the new code.

Hardware

GPIO

SERIAL_TX=PA_2    USER_BUTTON=PC_13
SERIAL_RX=PA_3    LED1       =PA_5

A0=PA_0  USART2RX D0=PA_3            D8 =PA_9
A1=PA_1  USART2TX D1=PA_2            D9 =PC_7
A2=PA_4           D2=PA_10   WIFI_CS=D10=PB_6 SPI_CS
A3=PB_0  WIFI_INT=D3=PB_3            D11=PA_7 SPI_MOSI
A4=PC_1      SDCS=D4=PB_5            D12=PA_6 SPI_MISO
A5=PC_0   WIFI_EN=D5=PB_4       LED1=D13=PA_5 SPI_SCK
             LED2=D6=PB_10  I2C1_SDA=D14=PB_9 Probe
                  D7=PA_8   I2C1_SCL=D15=PB_8 Probe

From: https://mbed.org/platforms/ST-Nucleo-F401RE/

Buttons

B1 USER: the user button is connected to the I/O PC13 (pin 2) of the STM32 microcontroller.

LEDs

The Nucleo F401RE provides a single user LED, LD2. LD2 is the green LED connected to Arduino signal D13 corresponding to MCU I/O PA5 (pin 21) or PB13 (pin 34) depending on the STM32target.

  • When the I/O is HIGH value, the LED is on.

  • When the I/O is LOW, the LED is off.

These LEDs are not used by the board port unless CONFIG_ARCH_LEDS is defined. In that case, the usage by the board port is defined in include/board.h and src/sam_leds.c. The LEDs are used to encode OS-related events as follows when the red LED (PE24) is available:

SYMBOL

Meaning

LD2

LED_STARTED

NuttX has been started

OFF

LED_HEAPALLOCATE

Heap has been allocated

OFF

LED_IRQSENABLED

Interrupts enabled

OFF

LED_STACKCREATED

Idle stack created

ON

LED_INIRQ

In an interrupt

No change

LED_SIGNAL

In a signal handler

No change

LED_ASSERTION

An assertion failed

No change

LED_PANIC

The system has crashed

Blinking

LED_IDLE

MCU is is sleep mode

Not used

Thus if LD2, NuttX has successfully booted and is, apparently, running normally. If LD2 is flashing at approximately 2Hz, then a fatal error has been detected and the system has halted.

Serial Consoles

USART1

Pins and Connectors:

RXD: PA11  CN10 pin 14
     PB7   CN7 pin 21
TXD: PA10  CN9 pin 3, CN10 pin 33
     PB6   CN5 pin 3, CN10 pin 17

NOTE: You may need to edit the include/board.h to select different USART1 pin selections.

TTL to RS-232 converter connection:

Nucleo CN10 STM32F401RE
----------- ------------
Pin 21 PA9  USART1_RX   *Warning you make need to reverse RX/TX on
Pin 33 PA10 USART1_TX    some RS-232 converters
Pin 20 GND
Pin 8  U5V

To configure USART1 as the console:

CONFIG_STM32_USART1=y
CONFIG_USART1_SERIALDRIVER=y
CONFIG_USART1_SERIAL_CONSOLE=y
CONFIG_USART1_RXBUFSIZE=256
CONFIG_USART1_TXBUFSIZE=256
CONFIG_USART1_BAUD=115200
CONFIG_USART1_BITS=8
CONFIG_USART1_PARITY=0
CONFIG_USART1_2STOP=0

USART2

Pins and Connectors:

RXD: PA3   CN9 pin 1 (See SB13, 14, 62, 63). CN10 pin 37
     PD6
TXD: PA2   CN9 pin 2(See SB13, 14, 62, 63). CN10 pin 35
     PD5

UART2 is the default in all of these configurations.

TTL to RS-232 converter connection:

Nucleo CN9  STM32F401RE
----------- ------------
Pin 1  PA3  USART2_RX   *Warning you make need to reverse RX/TX on
Pin 2  PA2  USART2_TX    some RS-232 converters

Solder Bridges. This configuration requires:

  • SB62 and SB63 Closed: PA2 and PA3 on STM32 MCU are connected to D1 and D0 (pin 7 and pin 8) on Arduino connector CN9 and ST Morpho connector CN10 as USART signals. Thus SB13 and SB14 should be OFF.

  • SB13 and SB14 Open: PA2 and PA3 on STM32F103C8T6 (ST-LINK MCU) are disconnected to PA3 and PA2 on STM32 MCU.

To configure USART2 as the console:

CONFIG_STM32_USART2=y
CONFIG_USART2_SERIALDRIVER=y
CONFIG_USART2_SERIAL_CONSOLE=y
CONFIG_USART2_RXBUFSIZE=256
CONFIG_USART2_TXBUFSIZE=256
CONFIG_USART2_BAUD=115200
CONFIG_USART2_BITS=8
CONFIG_USART2_PARITY=0
CONFIG_USART2_2STOP=0

USART6

Pins and Connectors:

RXD: PC7    CN5 pin2, CN10 pin 19
     PA12   CN10, pin 12
TXD: PC6    CN10, pin 4
     PA11   CN10, pin 14

To configure USART6 as the console:

CONFIG_STM32_USART6=y
CONFIG_USART6_SERIALDRIVER=y
CONFIG_USART6_SERIAL_CONSOLE=y
CONFIG_USART6_RXBUFSIZE=256
CONFIG_USART6_TXBUFSIZE=256
CONFIG_USART6_BAUD=115200
CONFIG_USART6_BITS=8
CONFIG_USART6_PARITY=0
CONFIG_USART6_2STOP=0

Virtual COM Port

Yet another option is to use UART2 and the USB virtual COM port. This option may be more convenient for long term development, but is painful to use during board bring-up.

Solder Bridges. This configuration requires:

  • SB62 and SB63 Open: PA2 and PA3 on STM32 MCU are disconnected to D1 and D0 (pin 7 and pin 8) on Arduino connector CN9 and ST Morpho connector CN10.

  • SB13 and SB14 Closed: PA2 and PA3 on STM32F103C8T6 (ST-LINK MCU) are connected to PA3 and PA2 on STM32 MCU to have USART communication between them. Thus SB61, SB62 and SB63 should be OFF.

Configuring USART2 is the same as given above.

Question: What BAUD should be configure to interface with the Virtual COM port? 115200 8N1?

Default

As shipped, SB62 and SB63 are open and SB13 and SB14 closed, so the virtual COM port is enabled.

Shields

RS-232 from Cutedigi.com

Supports a single RS-232 connected via:

Nucleo CN9  STM32F401RE  Cutedigi
----------- ------------ --------
Pin 1  PA3  USART2_RX    RXD
Pin 2  PA2  USART2_TX    TXD

Support for this shield is enabled by selecting USART2 and configuring SB13, 14, 62, and 63 as described above under “Serial Consoles”

Itead Joystick Shield

See http://imall.iteadstudio.com/im120417014.html for more information about this joystick.

Itead Joystick Connection:

--------- ----------------- ---------------------------------
ARDUINO   ITEAD             NUCLEO-F401
PIN NAME  SIGNAL            SIGNAL
--------- ----------------- ---------------------------------
 D3       Button E Output   PB3
 D4       Button D Output   PB5
 D5       Button C Output   PB4
 D6       Button B Output   PB10
 D7       Button A Output   PA8
 D8       Button F Output   PA9
 D9       Button G Output   PC7
 A0       Joystick Y Output PA0  ADC1_0
 A1       Joystick X Output PA1  ADC1_1
--------- ----------------- ---------------------------------

All buttons are pulled on the shield.  A sensed low value indicates
when the button is pressed.

NOTE: Button F cannot be used with the default USART1 configuration
because PA9 is configured for USART1_RX by default.  Use select
different USART1 pins in the board.h file or select a different
USART or select CONFIG_NUCLEO_F401RE_AJOY_MINBUTTONS which will
eliminate all but buttons A, B, and C.

Itead Joystick Signal interpretation:

--------- ----------------------- ---------------------------
BUTTON     TYPE                    NUTTX ALIAS
--------- ----------------------- ---------------------------
Button A  Large button A          JUMP/BUTTON 3
Button B  Large button B          FIRE/BUTTON 2
Button C  Joystick select button  SELECT/BUTTON 1
Button D  Tiny Button D           BUTTON 6
Button E  Tiny Button E           BUTTON 7
Button F  Large Button F          BUTTON 4
Button G  Large Button G          BUTTON 5
--------- ----------------------- ---------------------------

Itead Joystick configuration settings:

System Type -> STM32 Peripheral Support
  CONFIG_STM32_ADC1=y              : Enable ADC1 driver support

Drivers
  CONFIG_ANALOG=y                  : Should be automatically selected
  CONFIG_ADC=y                     : Should be automatically selected
  CONFIG_INPUT=y                   : Select input device support
  CONFIG_INPUT_AJOYSTICK=y         : Select analog joystick support

There is nothing in the configuration that currently uses the joystick. For testing, you can add the following configuration options to enable the analog joystick example at apps/examples/ajoystick:

CONFIG_NSH_ARCHINIT=y
CONFIG_EXAMPLES_AJOYSTICK=y
CONFIG_EXAMPLES_AJOYSTICK_DEVNAME="/dev/ajoy0"

STATUS:

2014-12-04:

  • Without ADC DMA support, it is not possible to sample both X and Y with a single ADC. Right now, only one axis is being converted.

  • There is conflicts with some of the Arduino data pins and the default USART1 configuration. I am currently running with USART1 but with CONFIG_NUCLEO_F401RE_AJOY_MINBUTTONS to eliminate the conflict.

  • Current showstopper: I appear to be getting infinite interrupts as soon as joystick button interrupts are enabled.

Configurations

nsh:

Configures the NuttShell (nsh) located at apps/examples/nsh for the Nucleo-F401RE board. The Configuration enables the serial interfaces on UART2. 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:

    1. Build and install the kconfig-mconf tool. See nuttx/README.txt see additional README.txt files in the NuttX tools repository.

    2. Execute ‘make menuconfig’ in nuttx/ in order to start the

      reconfiguration process.

  2. By default, this configuration uses the ARM EABI toolchain for Linux. That can easily be reconfigured, of course.:

    CONFIG_HOST_LINUX=y : Builds under Linux CONFIG_ARM_TOOLCHAIN_GNU_EABI=y : GNU EABI toolchain for Linux

  3. Although the default console is USART2 (which would correspond to the Virtual COM port) I have done all testing with the console device configured for USART1 (see instruction above under “Serial Consoles). I have been using a TTL-to-RS-232 converter connected as shown below:

    Nucleo CN10 STM32F401RE
    ----------- ------------
    Pin 21 PA9  USART1_RX   *Warning you make need to reverse RX/TX on
    Pin 33 PA10 USART1_TX    some RS-232 converters
    Pin 20 GND
    Pin 8  U5V