ST STM32L4R9AI-DISCO

This page discusses issues unique to NuttX configurations for the ST STM32L4R9AI Discovery board from ST Micro. See

https://www.st.com/content/st_com/en/products/evaluation-tools/product-evaluation-tools/mcu-eval-tools/stm32-mcu-eval-tools/stm32-mcu-discovery-kits/32l4r9idiscovery.html

STM32L4R9AI:

• Microprocessor: 32-bit ARM Cortex M4 at 120MHz STM32L4R9AI

• Memory: 2048 KB Flash and 192+64+384 KB SRAM

• ADC: 1x12-bit, 5 MSPS A/D converter: up to 14 external channels

• DAC: 2 channels

• DFSDM: 4 filters, 8 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 131 I/O ports with interrupt capability

• I2C: Up to 4 x 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

• OCTOSPI interface

• Camera interface

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

• CRC calculation unit

• RTC

Board features:

• Peripherals: 1 d-pad joystick, 2 x LED, AMOLED display, USC OTG FS, 2 x MEMS Digital Microphones, SAI codec, 16 Mbit PSRAM, 512 Mbit OCTOSPI Flash, current ammeter

• Debug: Serial wire debug and JTAG interfaces

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

mbed

The STM32L4R9AI-DISCO includes boot loader from mbed:

https://mbed.org/handbook/Homepage

Using the mbed loader:

1. Connect the board to the host PC using the USB connector.

2. A new file system will appear called DIS_L4R9AI; 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 board. The DIS_L49RAIO window will close then re-open and the board will be running the new code.

Hardware

Buttons

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

LEDs

The STM32L4R9AI-DISCO board provides two user LEDs, LD1 (orange) and LD2 (green). PB0 is LD1 (orange) PH4 is LD2 (green) - 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/stm32_autoleds.c. The LEDs are used to encode OS-related events as follows when the green LED (PH4) 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 is on, 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.

U[S]ARTs and 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
  Pin 33 PA10 USART1_TX
  Pin 20 GND
  Pin 8  U5V
  =========== ============

  Warning you make need to reverse RX/TX on some RS-232 converters

To configure USART1 as the console::

  CONFIG_STM32L4_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

TTL to RS-232 converter connection:

  =========== ============
  Nucleo CN9  STM32F4x1RE
  =========== ============
  Pin 1  PA3  USART2_RX
  Pin 2  PA2  USART2_TX
  =========== ============

  Warning you make need to reverse RX/TX on 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_STM32L4_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

UART4

Pins and Connectors:

RXD: PA1 -> CN11 D5
TXD: PA0 -> CN17 A4

To configure USART4 as the console:

CONFIG_STM32L4_UART4=y
CONFIG_USART4_SERIALDRIVER=y
CONFIG_USART4_SERIAL_CONSOLE=y
CONFIG_USART4_RXBUFSIZE=512
CONFIG_USART4_TXBUFSIZE=256
CONFIG_USART4_BAUD=2000000
CONFIG_USART4_BITS=8
CONFIG_USART4_PARITY=0
CONFIG_USART4_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.

Segger J-Link

Reference: https://www.segger.com/downloads/application-notes/AN00021

1. Connect J-Link VTref (1) to pin VDD

2. Connect J-Link SWDIO (7) to pin PA13

3. Connect J-Link SWCLK (9) to pin PA14

4. Connect J-Link SWO (13) to pin PB3

5. Connect J-Link RESET (15) to pin NRST

6. Connect J-Link 5V-Supply (19) to pin 5V

7. Connect J-Link GND (4) to pin GND

Jumpers on CN4 (ST-Link) must be removed for external debug.

Configurations

knsh

This is identical to the nsh configuration below except that (1) NuttX is built as a PROTECTED mode, monolithic module and the user applications are built separately and, as a consequence, (2) some features that are only available in the FLAT build are disabled.

It is recommends to use a special make command; not just ‘make’ but make with the following two arguments:

make pass1 pass2

In the normal case (just ‘make’), make will attempt to build both user- and kernel-mode blobs more or less interleaved. That actual works! However, for me it is very confusing so I prefer the above make command: Make the user-space binaries first (pass1), then make the kernel-space binaries (pass2)

NOTES:

1. At the end of the build, there will be several files in the top-level NuttX build directory:

   PASS1:

   nuttx_user.elf - The pass1 user-space ELF file nuttx_user.hex - The pass1 Intel HEX format file (selected in defconfig) User.map - Symbols in the user-space ELF file

   PASS2:

   nuttx - The pass2 kernel-space ELF file nuttx.hex - The pass2 Intel HEX file (selected in defconfig) System.map - Symbols in the kernel-space ELF file

   The J-Link programmer will except files in .hex, .mot, .srec, and .bin formats.

2. Combining .hex files. If you plan to use the .hex files with your debugger or FLASH utility, then you may need to combine the two hex files into a single .hex file. Here is how you can do that.

   1. The ‘tail’ of the nuttx.hex file should look something like this (with my comments added):

        $ tail nuttx.hex
        # 00, data records
        ...
        :10 9DC0 00 01000000000800006400020100001F0004
        :10 9DD0 00 3B005A0078009700B500D400F300110151
        :08 9DE0 00 30014E016D0100008D
        # 05, Start Linear Address Record
        :04 0000 05 0800 0419 D2
        # 01, End Of File record
        :00 0000 01 FF
      
      Use an editor such as vi to remove the 05 and 01 records.
      

   2. The ‘head’ of the nuttx_user.hex file should look something like this (again with my comments added):

        $ head nuttx_user.hex
        # 04, Extended Linear Address Record
        :02 0000 04 0801 F1
        # 00, data records
        :10 8000 00 BD89 01084C800108C8110208D01102087E
        :10 8010 00 0010 00201C1000201C1000203C16002026
        :10 8020 00 4D80 01085D80010869800108ED83010829
        ...
      
      Nothing needs to be done here.  The nuttx_user.hex file should
      be fine.
      

   3. Combine the edited nuttx.hex and un-edited nuttx_user.hex file to produce a single combined hex file:

      $ cat nuttx.hex nuttx_user.hex >combined.hex

      Then use the combined.hex file with the to write the FLASH image. If you do this a lot, you will probably want to invest a little time to develop a tool to automate these steps.

nsh

Configures the NuttShell (nsh) located at apps/examples/nsh for the STM32L4R9AI-DISCO board. The Configuration enables the serial interfaces on UART4. 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:

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

2. By default, this configuration uses the Generic 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  : Generic EABI toolchain for Linux
   

3. The default console is UART4

4. This example can be used to verify the OTGFS functionality. USB is not enabled in the default configuration but can be enabled with the following settings: (TODO: need to test!):

   CONFIG_STM32L4_OTGFS=y
   
   CONFIG_USBDEV=y
   CONFIG_USBDEV_SELFPOWERED=y
   

   These will enable the USB CDC/ACM serial device:

   CONFIG_CDCACM=y
   CONFIG_CDCACM_EP0MAXPACKET=64
   CONFIG_CDCACM_EPINTIN=1
   CONFIG_CDCACM_EPINTIN_FSSIZE=64
   CONFIG_CDCACM_EPINTIN_HSSIZE=64
   CONFIG_CDCACM_EPBULKOUT=3
   CONFIG_CDCACM_EPBULKOUT_FSSIZE=64
   CONFIG_CDCACM_EPBULKOUT_HSSIZE=512
   CONFIG_CDCACM_EPBULKIN=2
   CONFIG_CDCACM_EPBULKIN_FSSIZE=64
   CONFIG_CDCACM_EPBULKIN_HSSIZE=512
   CONFIG_CDCACM_NRDREQS=4
   CONFIG_CDCACM_NWRREQS=4
   CONFIG_CDCACM_BULKIN_REQLEN=96
   CONFIG_CDCACM_RXBUFSIZE=257
   CONFIG_CDCACM_TXBUFSIZE=193
   CONFIG_CDCACM_VENDORID=0x0525
   CONFIG_CDCACM_PRODUCTID=0xa4a7
   CONFIG_CDCACM_VENDORSTR="NuttX"
   CONFIG_CDCACM_PRODUCTSTR="CDC/ACM Serial"
   
   CONFIG_SERIAL_REMOVABLE=y
   

   These will enable the USB serial example at apps/examples/usbserial:

   CONFIG_BOARDCTL_USBDEVCTRL=y
   
   CONFIG_EXAMPLES_USBSERIAL=y
   CONFIG_EXAMPLES_USBSERIAL_BUFSIZE=512
   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
   

   Optional USB debug features::

   CONFIG_DEBUG_FEATURES=y
   CONFIG_DEBUG_USB=y
   CONFIG_ARCH_USBDUMP=y
   CONFIG_USBDEV_TRACE=y
   CONFIG_USBDEV_TRACE_NRECORDS=128
   CONFIG_USBDEV_TRACE_STRINGS=y
   CONFIG_USBDEV_TRACE_INITIALIDSET=y
   
   CONFIG_NSH_USBDEV_TRACE=y
   CONFIG_NSH_USBDEV_TRACEINIT=y
   CONFIG_NSH_USBDEV_TRACECLASS=y
   CONFIG_NSH_USBDEV_TRACETRANSFERS=y
   CONFIG_NSH_USBDEV_TRACECONTROLLER=y
   CONFIG_NSH_USBDEV_TRACEINTERRUPTS=y
   

nxhello

A simple NSH example using apps/examples/nxhello, a very simply test of basic NX functionality.