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libraries/lvgl/docs/integration/os/nuttx.rst

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+==========
+NuttX RTOS
+==========
+
+What is NuttX?
+--------------
+
+`NuttX <https://nuttx.apache.org/>`__ is a mature and secure real-time
+operating system (RTOS) with an emphasis on technical standards
+compliance and small size. It is scalable from 8-bit to 64-bit
+microcontrollers and microprocessors and compliant with the Portable
+Operating System Interface (POSIX) and the American National Standards
+Institute (ANSI) standards and with many Linux-like subsystems. The best
+way to think about NuttX is to think of it as a small Unix/Linux for
+microcontrollers.
+
+Highlights of NuttX
+~~~~~~~~~~~~~~~~~~~
+
+-  **Small** - Fits and runs in microcontrollers as small as 32 kB Flash
+   and 8 kB of RAM.
+-  **Compliant** - Strives to be as compatible as possible with POSIX
+   and Linux.
+-  **Versatile** - Supports many architectures (ARM, ARM Thumb, AVR,
+   MIPS, OpenRISC, RISC-V 32-bit and 64-bit, RX65N, x86-64, Xtensa,
+   Z80/Z180, etc.).
+-  **Modular** - Its modular design allows developers to select only
+   what really matters and use modules to include new features.
+-  **Popular** - NuttX is used by many companies around the world.
+   Probably you already used a product with NuttX without knowing it was
+   running NuttX.
+-  **Predictable** - NuttX is a preemptible Realtime kernel, so you can
+   use it to create predictable applications for realtime control.
+
+--------------
+
+Why NuttX + LVGL?
+-----------------
+
+Although NuttX has its own graphic library called
+`NX <https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=139629474>`__,
+LVGL is a good alternative because users could find more eye-candy demos
+and they can reuse code from previous projects. LVGL is an
+`Object-Oriented Component
+Based <https://blog.lvgl.io/2018-12-13/extend-lvgl-objects>`__
+high-level GUI library, that could fit very well for a RTOS with
+advanced features like NuttX. LVGL is implemented in C and its APIs are
+in C.
+
+Here are some advantages of using LVGL in NuttX
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+-  Develop GUI in Linux first and when it is done just compile it for
+   NuttX. Nothing more, no wasting of time.
+-  Usually, GUI development for low level RTOS requires multiple
+   iterations to get things right, where each iteration consists of
+   **``Change code`` > ``Build`` > ``Flash`` > ``Run``**. Using LVGL,
+   Linux and NuttX you can reduce this process and just test everything
+   on your computer and when it is done, compile it on NuttX and that is
+   it.
+
+NuttX + LVGL could be used for
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+-  GUI demos to demonstrate your board graphics capacities.
+-  Fast prototyping GUI for MVP (Minimum Viable Product) presentation.
+-  visualize sensor data directly and easily on the board without using
+   a computer.
+-  Final products with a GUI without a touchscreen (i.e. 3D Printer
+   Interface using Rotary Encoder to Input data).
+-  Final products with a touchscreen (and all sorts of bells and
+   whistles).
+
+--------------
+
+How to get started with NuttX and LVGL?
+---------------------------------------
+
+There are many boards in the `NuttX
+mainline <https://github.com/apache/incubator-nuttx>`__ with support for
+LVGL. Let's use the
+`STM32F429IDISCOVERY <https://www.st.com/en/evaluation-tools/32f429idiscovery.html>`__
+as an example because it is a very popular board.
+
+First you need to install the pre-requisites on your system
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Let's use the `Windows Subsystem for
+Linux <https://acassis.wordpress.com/2018/01/10/how-to-build-nuttx-on-windows-10/>`__
+
+.. code:: shell
+
+   $ sudo apt-get install automake bison build-essential flex gcc-arm-none-eabi gperf git libncurses5-dev libtool libusb-dev libusb-1.0.0-dev pkg-config kconfig-frontends openocd
+
+Now let's create a workspace to save our files
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code:: shell
+
+   $ mkdir ~/nuttxspace
+   $ cd ~/nuttxspace
+
+Clone the NuttX and Apps repositories:
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code:: shell
+
+   $ git clone https://github.com/apache/incubator-nuttx nuttx
+   $ git clone https://github.com/apache/incubator-nuttx-apps apps
+
+Configure NuttX to use the stm32f429i-disco board and the LVGL Demo
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code:: shell
+
+   $ ./tools/configure.sh stm32f429i-disco:lvgl
+   $ make
+
+If everything went fine you should have now the file ``nuttx.bin`` to
+flash on your board:
+
+.. code:: shell
+
+   $ ls -l nuttx.bin
+   -rwxrwxr-x 1 alan alan 287144 Jun 27 09:26 nuttx.bin
+
+Flashing the firmware in the board using OpenOCD:
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code:: shell
+
+   $ sudo openocd -f interface/stlink-v2.cfg -f target/stm32f4x.cfg -c init -c "reset halt" -c "flash write_image erase nuttx.bin 0x08000000"
+
+Reset the board and using the 'NSH>' terminal start the LVGL demo:
+
+.. code:: shell
+
+   nsh> lvgldemo
+
+Where can I find more information?
+----------------------------------
+
+-  This blog post: `LVGL on
+   LPCXpresso54628 <https://acassis.wordpress.com/2018/07/19/running-nuttx-on-lpcxpresso54628-om13098/>`__
+-  NuttX mailing list: `Apache NuttX Mailing
+   List <http://nuttx.incubator.apache.org/community/>`__