ST Nucleo L476RG

This page discusses issues unique to NuttX configurations for the ST NucleoL476RG board from ST Micro. See

http://www.st.com/nucleo-l476rg

NucleoL476RG:

Microprocessor: 32-bit ARM Cortex M4 at 80MHz STM32L476RGT6
Memory: 1024 KB Flash and 96+32 KB SRAM
ADC: 2×12-bit, 2.4 MSPS A/D converter: up to 24 channels
DMA: 16-stream DMA controllers with FIFOs and burst support
Timers: Up to 11 timers: up to eight 16-bit, two 32-bit timers, two watchdog timers, and a SysTick timer
GPIO: Up to 51 I/O ports with interrupt capability
I2C: Up to 3 × I2C interfaces
USARTs: Up to 3 USARTs, 2 UARTs, 1 LPUART
SPIs: Up to 3 SPIs
SAIs: Up to 2 dual-channel audio interfaces
CAN interface
SDIO interface
QSPI interface
USB: USB 2.0 full-speed device/host/OTG controller with on-chip PHY
CRC calculation unit
RTC

Board features:

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-L476RG for more information about these boards.

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.

The NuttX buildroot Toolchain (see below), or
Any generic arm-none-eabi GNU toolchain.

All testing has been conducted using the NuttX Codesourcery toolchain. To use a different toolchain, you simply need to modify the configuration. As an example:

CONFIG_ARM_TOOLCHAIN_GNU_EABI : Generic arm-none-eabi toolchain

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).

Using Sourcery CodeBench from http://www.mentor.com/embedded-software/sourcery-tools/sourcery-codebench/overview Download and install the latest version (as of this writing it was sourceryg++-2013.05-64-arm-none-eabi)

Import the project from git. File->import->Git-URI, then import a Exiting code as a Makefile progject from the working directory the git clone was done to.

Select the Sourcery CodeBench for ARM EABI. N.B. You must do one command line build, before the make will work in CodeBench.

Native Build

Here are a few tips before you start that effort:

Select the toolchain that you will be using in your .config file
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.
Set up include paths: You will need include/, arch/arm/src/stm32, arch/arm/src/common, arch/arm/src/armv7-m, and sched/.
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.

You must have already configured NuttX in <some-dir>/nuttx.:

$ tools/configure.sh nucleo-l476rg:nsh
$ make qconfig
$ V=1 make context all 2>&1 | tee mout

Download the latest buildroot package into <some-dir>
unpack the buildroot tarball. The resulting directory may have versioning information on it like buildroot-x.y.z. If so, rename <some-dir>/buildroot-x.y.z to <some-dir>/buildroot.
cd <some-dir>/buildroot
cp boards/cortexm3-eabi-defconfig-4.6.3 .config
make oldconfig
make
Make sure that the PATH variable includes the path to the newly built binaries.

See the file boards/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 toolchain; instead use the GCC 4.3.3 EABI toolchain.

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.

You must have already configured NuttX in <some-dir>/nuttx.

tools/configure.sh lpcxpresso-lpc1768:<sub-dir>
Download the latest buildroot package into <some-dir>
unpack the buildroot tarball. The resulting directory may have versioning information on it like buildroot-x.y.z. If so, rename <some-dir>/buildroot-x.y.z to <some-dir>/buildroot.
cd <some-dir>/buildroot
cp boards/cortexm3-defconfig-nxflat .config
make oldconfig
make
Make sure that the PATH variable includes the path to the newly built NXFLAT binaries.

mbed

The Nucleo-L476RG includes boot loader from mbed:

https://mbed.org/platforms/ST-Nucleo-L476RG/ https://mbed.org/handbook/Homepage

Using the mbed loader:

Connect the Nucleo-F4x1RE to the host PC using the USB connector.
A new file system will appear called NUCLEO; open it with Windows Explorer (assuming that you are using Windows).
Drag and drop nuttx.bin into the MBED window. This will load the nuttx.bin binary into the Nucleo-F4x1RE. The NUCLEO window will close then re-open and the Nucleo-F4x1RE 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-L476RG/

Buttons

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

LEDs

The Nucleo L476RG 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 STM32F4x1RE
----------- ------------
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  STM32F4x1RE
----------- ------------
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

STM32F4x1RE

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=F4x1

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_L476RG_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_L476RG_AJOY_MINBUTTONS to eliminate the conflict.
Current showstopper: I appear to be getting infinite interrupts as soon as joystick button interrupts are enabled.

Other External Hardware/Devices

Using external SPI SDCard

It is possible to use external SDCard over SPI with the nucleo-stm32l476rg Cortex-M4. This option will or can broaden the functionality in your project, solution or application.

In this NuttX project we attach an MH-SD Card Module (SPI). [http://www.geeetech.com/wiki/index.php/Arduino_SD_card_Module]

Configurations

nsh

Configures the NuttShell (nsh) located at apps/examples/nsh for the Nucleo-L476RG 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:

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.
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
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 STM32F4x1RE
----------- ------------
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
```

nxdemo

This is an NSH configuration that enables the NX graphics demo at apps/examples/nxdemo. It uses the PCD8544 display on SPI1.

Nucleo CN10	STM32L4x6RG
Pin 31 PB3	SLCK
Pin 27 PB4	MISO
Pin 29 PB5	MOSI
Pin 25 PB10	CS

Nucleo CN7	STM32L4x6RG
Pin 18 +5V	5V
Pin 22 GND	GND