.. zephyr:board:: nucleo_h755zi_q

Overview
********

The NUCLEO-H755ZI-Q board, based on the MB1363 reference board, provides an affordable and
flexible way for users to try out new concepts and build prototypes on the STM32H755ZIT6
microcontroller.

The ST Zio connector, which extends the ARDUINO® Uno V3 connectivity, and
the ST morpho headers provide an easy means of expanding the functionality of the Nucleo
open development platform with a wide choice of specialized shields.
The NUCLEO-H755ZI-Q board does not require any separate probe as it integrates
the ST-LINK V3 debugger/programmer.

Key Features

- STM32H755ZIT6 microcontroller in LQFP144 package
- Ethernet compliant with IEEE-802.3-2002 (depending on STM32 support)
- USB OTG or full-speed device (depending on STM32 support)
- 3 user LEDs
- 2 user and reset push-buttons
- 32.768 kHz crystal oscillator
- Board connectors:

 - USB with Micro-AB
 - Ethernet RJ45 (depending on STM32 support)
 - SWDST Zio connector including Arduino* Uno V3ST
 - ST morpho expansion

- Flexible power-supply options: ST-LINK USB VBUS or external sources
- External or internal SMPS to generate Vcore logic supply
- On-board ST-LINK/V3 debugger/programmer with USB re-enumeration
- capability: mass storage, virtual COM port and debug port
- USB OTG full speed or device only

More information about the board can be found at the `Nucleo H755ZI-Q website`_.

Hardware
********

Nucleo H755ZI-Q provides the following hardware components:

- STM32H755ZI in LQFP144 package
- ARM 32-bit Cortex-M7 CPU with FPU
- ARM 32-bit Cortex-M4 CPU with FPU
- Chrom-ART Accelerator
- Hardware JPEG Codec
- 480 MHz max CPU frequency
- VDD from 1.62 V to 3.6 V
- 2 MB Flash
- 1 MB SRAM
- High-resolution timer (2.1 ns)
- 32-bit timers(2)
- 16-bit timers(12)
- SPI(6)
- I2C(4)
- I2S (3)
- USART(4)
- UART(4)
- USB OTG Full Speed and High Speed(1)
- USB OTG Full Speed(1)
- CAN-FD(2)
- SAI(2)
- SPDIF_Rx(4)
- HDMI_CEC(1)
- Dual Mode Quad SPI(1)
- Camera Interface
- GPIO (up to 114) with external interrupt capability
- 16-bit ADC(3) with 36 channels / 3.6 MSPS
- 12-bit DAC with 2 channels(2)
- True Random Number Generator (RNG)
- 16-channel DMA
- LCD-TFT Controller with XGA resolution
- CRYPT and HASH peripherals

Supported Features
==================

.. zephyr:board-supported-hw::

For more details please refer to `STM32 Nucleo-144 board User Manual`_.

Default Zephyr Peripheral Mapping:
----------------------------------

The Nucleo H755ZI board features a ST Zio connector (extended Arduino Uno V3)
and a ST morpho connector. Board is configured as follows:

- USART_3 TX/RX : PD8/PD9 (ST-Link Virtual Port Com)
- USER_PB : PC13
- LD1 : PA5
- LD2 : PE1
- LD3 : PB14
- I2C : PB8, PB9
- CAN/CANFD : PD0, PD1

System Clock
------------

Nucleo H755ZI-Q System Clock can be driven by an internal or external
oscillator, as well as the main PLL clock. By default, the System clock is
driven by the PLL clock at 480MHz, driven by an 8MHz high-speed external clock.

Serial Port
-----------

Nucleo H755ZI-Q board has 4 UARTs and 4 USARTs. The Zephyr console output is
assigned to USART3. Default settings are 115200 8N1.

CAN, CANFD
----------

Requires an external CAN or CANFD transceiver.

Resources sharing
-----------------

The dual core nature of STM32H755 SoC requires sharing HW resources between the
two cores. This is done in 3 ways:

- **Compilation**: Clock configuration is only accessible to M7 core. M4 core only
  has access to bus clock activation and deactivation.
- **Static pre-compilation assignment**: Peripherals such as a UART are assigned in
  devicetree before compilation. The user must ensure peripherals are not assigned
  to both cores at the same time.
- **Run time protection**: Interrupt-controller and GPIO configurations could be
  accessed by both cores at run time. Accesses are protected by a hardware semaphore
  to avoid potential concurrent access issues.

Programming and Debugging
*************************

.. zephyr:board-supported-runners::

Nucleo H755ZI-Q board includes an ST-LINK/V3 embedded debug tool interface.

Applications for the ``nucleo_h755zi_q`` board should be built per core target,
using either ``nucleo_h755zi_q/stm32h755xx/m7`` or ``nucleo_h755zi_q/stm32h755xx/m4``
as the target (see :ref:`build_an_application` and :ref:`application_run` for more
details).

.. note::

   Check if the board's ST-LINK/V3 has the newest firmware version. It can be
   updated with `STM32CubeProgrammer`_

Flashing
========

The board is configured to be flashed using west `STM32CubeProgrammer`_ runner
for both cores, so its :ref:`installation <stm32cubeprog-flash-host-tools>` is required.
The target core is detected automatically.

It is advised to use `STM32CubeProgrammer`_ to check and update option bytes
configuration and flash ``nucleo_h755zi_q/stm32h755xx/m7`` and
``nucleo_h755zi_q/stm32h755xx/m4`` board targets.

By default:

  - CPU0 (Cortex-M7) boot address is set to 0x08000000 (OB: BOOT_CM7_ADD0)
  - CPU1 (Cortex-M4) boot address is set to 0x08100000 (OB: BOOT_CM4_ADD0)

Also, default out of the box board configuration enables CM7 and CM4 boot when
board is powered (Option bytes BCM7 and BCM4 are checked).
In that configuration, Kconfig boot option ``STM32H7_BOOT_CM4_CM7`` should be selected.
Zephyr flash configuration has been set to meet these default settings.

Alternatively, OpenOCD or JLink can also be used to flash the board using
the ``--runner`` (or ``-r``) option:

.. code-block:: console

   $ west flash --runner openocd
   $ west flash --runner jlink

Flashing an application to STM32H755ZI M7 Core
----------------------------------------------
First, connect the NUCLEO-H755ZI-Q to your host computer using
the USB port to prepare it for flashing. Then build and flash your application.

Here is an example for the :zephyr:code-sample:`hello_world` application.

Run a serial host program to connect with your NUCLEO-H755ZI-Q board.

.. code-block:: console

   $ minicom -b 115200 -D /dev/ttyACM0

or use screen:

.. code-block:: console

   $ screen /dev/ttyACM0 115200

Build and flash the application:

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: nucleo_h755zi_q/stm32h755xx/m7
   :goals: build flash

You should see the following message on the console:

.. code-block:: console

   $ Hello World! nucleo_h755zi_q/stm32h755xx/m7

.. note::
  Sometimes, flashing via OpenOCD does not work. It is necessary to erase the flash
  (with STM32CubeProgrammer for example) to make it work again.

Similarly, you can build and flash samples on the M4 target. For this, please
take care of the resource sharing (UART port used for console for instance).

Here is an example for the :zephyr:code-sample:`blinky` application on M4 core.

.. zephyr-app-commands::
   :zephyr-app: samples/basic/blinky
   :board: nucleo_h755zi_q/stm32h755xx/m4
   :goals: build flash

.. note::

   Flashing both M4 and M7 and pushing RESTART button on the board leads
   to LD1 and LD2 flashing simultaneously.

Debugging
=========

You can debug an application on the Cortex M7 core in the usual way.
Here is an example for the :zephyr:code-sample:`hello_world` application.

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: nucleo_h755zi_q/stm32h755xx/m7
   :maybe-skip-config:
   :goals: debug

Debugging a Zephyr application on Cortex M4 side with west is currently not
available. As a workaround, `STM32CubeIDE`_ can be used.

.. _Nucleo H755ZI-Q website:
   https://www.st.com/en/evaluation-tools/nucleo-h755zi-q.html

.. _STM32 Nucleo-144 board User Manual:
   https://www.st.com/resource/en/user_manual/dm00499171-stm32h7-nucleo144-boards-mb1363-stmicroelectronics.pdf

.. _STM32H755ZI on www.st.com:
   https://www.st.com/en/microcontrollers-microprocessors/stm32h755zi.html

.. _STM32H755 reference manual:
   https://www.st.com/resource/en/reference_manual/dm00176879-stm32h745755-and-stm32h747757-advanced-armbased-32bit-mcus-stmicroelectronics.pdf

.. _OpenOCD installing Debug Version:
   https://github.com/zephyrproject-rtos/openocd

.. _OpenOCD installing with ST-LINK V3 support:
   https://mbd.kleier.net/integrating-st-link-v3.html

.. _STM32CubeIDE:
   https://www.st.com/en/development-tools/stm32cubeide.html

.. _STM32CubeProgrammer:
   https://www.st.com/en/development-tools/stm32cubeprog.html
