boards: st: add nucleo_u031r8 board support

add board support for nucleo_u031r8

Signed-off-by: Fabrice DJIATSA <fabrice.djiatsa-ext@st.com>

boards/st/nucleo_u031r8/Kconfig.nucleo_u031r8

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+# Copyright (c) 2024 STMicroelectronics
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_NUCLEO_U031R8
+	select SOC_STM32U031XX

boards/st/nucleo_u031r8/arduino_r3_connector.dtsi

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+/*
+ * Copyright (c) 2024 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	arduino_header: connector {
+		compatible = "arduino-header-r3";
+		#gpio-cells = <2>;
+		gpio-map-mask = <0xffffffff 0xffffffc0>;
+		gpio-map-pass-thru = <0 0x3f>;
+		gpio-map = <0 0 &gpioa 0 0>,	/* A0 */
+			   <1 0 &gpioa 1 0>,	/* A1 */
+			   <2 0 &gpioa 4 0>,	/* A2 */
+			   <3 0 &gpiob 0 0>,	/* A3 */
+			   <4 0 &gpioc 1 0>,	/* A4 */
+			   <5 0 &gpioc 0 0>,	/* A5 */
+			   <6 0 &gpioa 3 0>,	/* D0 */
+			   <7 0 &gpioa 2 0>,	/* D1 */
+			   <8 0 &gpioa 10 0>,	/* D2 */
+			   <9 0 &gpiob 3 0>,	/* D3 */
+			   <10 0 &gpiob 5 0>,	/* D4 */
+			   <11 0 &gpiob 4 0>,	/* D5 */
+			   <12 0 &gpiob 10 0>,	/* D6 */
+			   <13 0 &gpioa 8 0>,	/* D7 */
+			   <14 0 &gpioa 9 0>,	/* D8 */
+			   <15 0 &gpioc 7 0>,	/* D9 */
+			   <16 0 &gpiob 6 0>,	/* D10 */
+			   <17 0 &gpioa 7 0>,	/* D11 */
+			   <18 0 &gpioa 6 0>,	/* D12 */
+			   <19 0 &gpioa 5 0>,	/* D13 */
+			   <20 0 &gpiob 9 0>,	/* D14 */
+			   <21 0 &gpiob 8 0>;	/* D15 */
+	};
+};
+
+arduino_serial: &usart1 {};

boards/st/nucleo_u031r8/board.cmake

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+board_runner_args(stm32cubeprogrammer "--port=swd" "--reset-mode=hw")
+
+board_runner_args(pyocd "--target=stm32u031r8tx")
+
+board_runner_args(jlink "--device=STM32U031R8" "--reset-after-load")
+
+include(${ZEPHYR_BASE}/boards/common/stm32cubeprogrammer.board.cmake)
+include(${ZEPHYR_BASE}/boards/common/pyocd.board.cmake)
+include(${ZEPHYR_BASE}/boards/common/jlink.board.cmake)

boards/st/nucleo_u031r8/board.yml

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+board:
+  name: nucleo_u031r8
+  vendor: st
+  socs:
+    - name: stm32u031xx

boards/st/nucleo_u031r8/doc/index.rst

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+.. _nucleo_u031r8_board:
+
+ST Nucleo U031R8
+################
+
+Overview
+********
+
+The Nucleo U031R8 board, featuring an ARM Cortex-M0+ based STM32U031R8 MCU,
+provides an affordable and flexible way for users to try out new concepts and
+build prototypes by choosing from the various combinations of performance and
+power consumption features. Here are some highlights of the Nucleo U031R8
+board:
+
+
+- STM32U031R8 microcontroller in LQFP48 package
+- Two types of extension resources:
+
+  - Arduino Uno V3 connectivity
+  - ST morpho extension pin headers for full access to all STM32U0 I/Os
+
+- On-board STLINK-V2EC debugger/programmer with USB re-enumeration
+  capability: mass storage, Virtual COM port, and debug port
+- Flexible board power supply:
+
+  - USB VBUS or external source(3.3V, 5V, 7 - 12V)
+
+- User LED shared with ARDUINO |reg| Uno V3
+- Two push-buttons: USER and RESET
+- USB Type-C |reg| connector for the ST-LINK
+
+Hardware
+********
+
+The STM32U031x4/6/8 devices are an ultra-low-power microcontrollers family (STM32U0
+Series) based on the high-performance Arm |reg| Cortex |reg|-M0+ 32-bit RISC core.
+They operate at a frequency of up to 56 MHz.
+
+- Includes ST state-of-the-art patented technology
+- Ultra-low-power with FlexPowerControl:
+
+  - 1.71 V to 3.6 V power supply
+  - -40 °C to +85/125 °C temperature range
+  - 130 nA VBAT mode: supply for RTC, 9 x 32-bit backup registers
+  - 16 nA Shutdown mode (4 wake-up pins)
+  - 30 nA Standby mode (6 wake-up pins) without RTC
+  - 160 nA Standby mode with RTC
+  - 630 nA Stop 2 mode with RTC
+  - 515 nA Stop 2 mode without RTC
+  - 4 µA wake-up from Stop mode
+  - 52 µA/MHz Run mode
+  - Brownout reset
+
+- Core:
+
+  - 32-bit Arm |reg| Cortex |reg|-M0+ CPU, frequency up to 56 MHz
+
+- ART Accelerator:
+
+  - 1-Kbyte instruction cache allowing 0-wait-state execution from flash memory
+
+- Benchmarks:
+
+  - 1.13 DMIPS/MHz (Drystone 2.1)
+  - 134 CoreMark |reg| (2.4 CoreMark/MHz at 56 MHz)
+  - 430 ULPMark™-CP
+  - 167 ULPMark™-PP
+  - 20.3 ULPMark™-CM
+
+- Memories:
+
+  - 64-Kbyte single bank flash memory, proprietary code readout protection
+  - 12-Kbyte SRAM with hardware parity check
+
+- General-purpose input/outputs:
+
+  - Up to 53 fast I/Os, most of them 5 V‑tolerant
+
+- Clock management:
+
+  - 4 to 48 MHz crystal oscillator
+  - 32 kHz crystal oscillator for RTC (LSE)
+  - Internal 16 MHz factory-trimmed RC (±1%)
+  - Internal low-power 32 kHz RC (±5%)
+  - Internal multispeed 100 kHz to 48 MHz oscillator,
+    auto-trimmed by LSE (better than ±0.25 % accuracy)
+  - PLL for system clock, ADC
+
+- Security:
+
+  - Customer code protection
+  - Robust read out protection (RDP): 3 protection level states
+    and password-based regression (128-bit PSWD)
+  - Hardware protection feature (HDP)
+  - Secure boot
+  - True random number generation, candidate for NIST SP 800-90B certification
+  - Candidate for Arm |reg| PSA level 1 and SESIP level 3 certifications
+  - 5 passive anti-tamper pins
+  - 96-bit unique ID
+
+- Up to 9 timers, RTC, and 2 watchdogs :
+
+  - 1x 16-bit advanced motor-control, 1x 32-bit and 3x 16-bit general purpose,
+    2x 16-bit basic, 2x low-power 16-bit timers (available in Stop mode),
+    2x watchdogs, SysTick timer
+  - RTC with hardware calendar, alarms and calibration
+
+- Up to 16 communication peripherals:
+
+  - 6x USARTs/LPUARTs (SPI, ISO 7816, LIN, IrDA, modem)
+  - 3x I2C interfaces supporting Fast-mode and Fast-mode Plus (up to 1 Mbit/s)
+  - 2x SPIs, plus 4x USARTs in SPI mode
+  - IRTIM (Infrared interface)
+
+- Rich analog peripherals (independent supply):
+
+  - 1x 12-bit ADC (0.4 µs conversion time), up to 16-bit with hardware oversampling
+  - 1x 12-bit DAC output channel, low-power sample and hold
+  - 1x general-purpose operational amplifier with built-in PGA (variable gain up to 16)
+  - 1x ultra-low-power comparator
+
+- ECOPACK2 compliant packages
+
+More information about STM32U031R8 can be found here:
+
+- `STM32U031R8 on www.st.com`_
+- `STM32U031R8 reference manual`_
+
+Supported Features
+==================
+
+The Zephyr _nucleo_u031r8_ board configuration supports the following hardware features:
+
++-----------+------------+-------------------------------------+
+| Interface | Controller | Driver/Component                    |
++===========+============+=====================================+
+| CLOCK     | on-chip    | reset and clock control             |
++-----------+------------+-------------------------------------+
+| GPIO      | on-chip    | gpio                                |
++-----------+------------+-------------------------------------+
+| NVIC      | on-chip    | nested vector interrupt controller  |
++-----------+------------+-------------------------------------+
+
+
+Other hardware features are not yet supported on this Zephyr port.
+
+The default configuration can be found in the defconfig file:
+:zephyr_file:`boards/st/nucleo_u031r8/nucleo_u031r8_defconfig`
+
+
+Connections and IOs
+===================
+
+Nucleo U031R8 Board has 10 GPIO controllers. These controllers are responsible
+for pin muxing, input/output, pull-up, etc.
+
+For more details please refer to `STM32U031 User Manual`_.
+
+Default Zephyr Peripheral Mapping:
+----------------------------------
+
+- LD1 : PA5
+- UART_1_TX : PA9
+- UART_1_RX : PA10
+- UART_2_TX : PA2
+- UART_2_RX : PA3
+- USER_PB : PC13
+
+System Clock
+------------
+
+Nucleo U031R8 System Clock could be driven by internal or external oscillator,
+as well as main PLL clock. By default System clock is driven by PLL clock at
+48MHz, driven by 4MHz medium speed internal oscillator.
+
+Serial Port
+-----------
+
+Nucleo U031R8 board has 4 U(S)ARTs. The Zephyr console output is assigned to
+USART2. Default settings are 115200 8N1.
+
+
+Programming and Debugging
+*************************
+
+Nucleo U031R8 board includes an ST-LINK/V3 embedded debug tool interface.
+This probe allows to flash the board using various tools.
+
+Flashing
+========
+
+Board is configured to be flashed using west STM32CubeProgrammer runner.
+Installation of `STM32CubeProgrammer`_ is then required to flash the board.
+
+Alternatively, pyocd or jlink via an external probe can also be used to flash
+and debug the board if west is told to use it as runner, which can be done by
+passing either or ``-r pyocd``, or ``-r jlink``.
+
+For pyocd additional target information needs to be installed.
+This can be done by executing the following commands.
+
+.. code-block:: console
+
+   $ pyocd pack --update
+   $ pyocd pack --install stm32u0
+
+
+Flashing an application to Nucleo U031R8
+------------------------------------------
+
+Connect the Nucleo U031R8 to your host computer using the USB port.
+Then build and flash an application. Here is an example for the
+:ref:`hello_world` application.
+
+Run a serial host program to connect with your Nucleo board:
+
+.. code-block:: console
+
+   $ minicom -D /dev/ttyACM0
+
+Then build and flash the application.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/hello_world
+   :board: nucleo_u031r8
+   :goals: build flash
+
+You should see the following message on the console:
+
+.. code-block:: console
+
+   Hello World! nucleo_u031r8
+
+Debugging
+=========
+
+Default flasher for this board is openocd. It could be used in the usual way.
+Here is an example for the :zephyr:code-sample:`blinky` application.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/basic/blinky
+   :board: nucleo_u031r8
+   :goals: debug
+
+Note: Check the ``build/tfm`` directory to ensure that the commands required by these scripts
+(``readlink``, etc.) are available on your system. Please also check ``STM32_Programmer_CLI``
+(which is used for initialization) is available in the PATH.
+
+.. _NUCLEO_U031R8 website:
+  https://www.st.com/en/evaluation-tools/nucleo-u031r8.html
+
+.. _STM32U031 User Manual:
+   https://www.st.com/resource/en/user_manual/um3261-stm32u0-series-safety-manual-stmicroelectronics.pdf
+
+.. _STM32U031R8 on www.st.com:
+   https://www.st.com/en/microcontrollers-microprocessors/stm32u031r8
+
+.. _STM32U031R8 reference manual:
+   https://www.st.com/resource/en/reference_manual/rm0503-stm32u0-series-advanced-armbased-32bit-mcus-stmicroelectronics.pdf
+
+.. _STM32CubeProgrammer:
+   https://www.st.com/en/development-tools/stm32cubeprog.html

boards/st/nucleo_u031r8/nucleo_u031r8.dts

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+/*
+ * Copyright (c) 2024 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+#include <st/u0/stm32u031X8.dtsi>
+#include <st/u0/stm32u031r8tx-pinctrl.dtsi>
+#include "arduino_r3_connector.dtsi"
+#include <zephyr/dt-bindings/input/input-event-codes.h>
+
+/ {
+	model = "STMicroelectronics STM32U83RC-NUCLEO board";
+	compatible = "st,stm32u031r8-nucleo";
+
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	chosen {
+		zephyr,console = &usart2;
+		zephyr,shell-uart = &usart2;
+		zephyr,sram = &sram0;
+		zephyr,flash = &flash0;
+	};
+
+	leds: leds {
+		compatible = "gpio-leds";
+		green_led_1: led_1 {
+			gpios = <&gpioa 5 GPIO_ACTIVE_HIGH>;
+			label = "User LD4";
+		};
+	};
+
+	gpio_keys {
+		compatible = "gpio-keys";
+		user_button: button {
+			label = "User";
+			gpios = <&gpioc 13 GPIO_ACTIVE_HIGH>;
+			zephyr,code = <INPUT_KEY_0>;
+		};
+	};
+
+	aliases {
+		led0 = &green_led_1;
+		sw0 = &user_button;
+	};
+};
+
+&usart1 {
+	pinctrl-0 = <&usart1_tx_pa9 &usart1_rx_pa10>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	status = "okay";
+};
+
+&usart2 {
+	pinctrl-0 = <&usart2_tx_pa2 &usart2_rx_pa3>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	status = "okay";
+};
+
+&clk_hsi {
+	status = "okay";
+};
+
+&pll {
+	div-m = <1>;
+	mul-n = <6>;
+	div-p = <2>;
+	div-q = <2>;
+	div-r = <2>;
+	clocks = <&clk_hsi>;
+	status = "okay";
+};
+
+&rcc {
+	clocks = <&pll>;
+	clock-frequency = <DT_FREQ_M(48)>;
+	ahb-prescaler = <1>;
+	apb1-prescaler = <1>;
+};

boards/st/nucleo_u031r8/nucleo_u031r8.yaml

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+identifier: nucleo_u031r8
+name: ST Nucleo U031R8
+type: mcu
+arch: arm
+toolchain:
+  - zephyr
+supported:
+  - arduino_gpio
+  - gpio
+  - usart
+ram: 12
+flash: 64

boards/st/nucleo_u031r8/nucleo_u031r8_defconfig

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+# SPDX-License-Identifier: Apache-2.0
+
+# Enable MPU
+CONFIG_ARM_MPU=y
+
+# Serial Drivers
+CONFIG_SERIAL=y
+CONFIG_UART_INTERRUPT_DRIVEN=y
+
+# enable console
+CONFIG_CONSOLE=y
+CONFIG_UART_CONSOLE=y
+
+# GPIO Controller
+CONFIG_GPIO=y
+
+# Enable Clocks
+CONFIG_CLOCK_CONTROL=y
+
+# enable pin controller
+CONFIG_PINCTRL=y