docs(NuttX): Add more NuttX docs (#8235)

This commit is contained in:
Liam Howatt
2025-05-13 10:44:12 +08:00
committed by GitHub
parent e0b65f78cc
commit f11f1322d9
+169 -19
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@@ -3,7 +3,7 @@ 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
@@ -15,7 +15,7 @@ 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.
@@ -32,10 +32,8 @@ Highlights of 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>`__,
@@ -48,19 +46,19 @@ 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,
**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.
@@ -71,10 +69,8 @@ NuttX + LVGL could be used for
- 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
@@ -83,7 +79,7 @@ LVGL. Let's use the
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/>`__
@@ -93,21 +89,62 @@ Linux <https://acassis.wordpress.com/2018/01/10/how-to-build-nuttx-on-windows-10
$ 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-block:: shell
$ mkdir ~/nuttxspace
$ cd ~/nuttxspace
Clone the NuttX and Apps repositories:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Clone the NuttX and Apps repositories
-------------------------------------
.. code-block:: shell
$ git clone https://github.com/apache/incubator-nuttx nuttx
$ git clone https://github.com/apache/incubator-nuttx-apps apps
NuttX Simulator
---------------
The NuttX simulator allows you to run NuttX and LVGL on your PC.
This can be especially useful for developing LVGL UIs with immediate
visual feedback, and also developing platform independent NuttX apps.
Configure NuttX to use the ``sim`` board and the LVGL Demo
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. code-block:: shell
$ ./tools/configure.sh sim:lvgl_fb
$ make
If everything went fine you should have now the file ``nuttx``
.. code-block:: shell
$ ls -l nuttx
-rwxr-xr-x 1 root root 2819920 May 12 15:01 nuttx
Running the NuttX Simulator
~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. code-block:: shell
$ ./nuttx
Using the 'NSH>' terminal start the LVGL demo:
.. code-block:: shell
nsh> lvgldemo
NuttX On-Device
---------------
If you don't have an STM32F429I-DISCO, this process will be similar
for other boards.
Configure NuttX to use the stm32f429i-disco board and the LVGL Demo
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -124,8 +161,8 @@ flash on your board:
$ ls -l nuttx.bin
-rwxrwxr-x 1 alan alan 287144 Jun 27 09:26 nuttx.bin
Flashing the firmware in the board using OpenOCD:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Flashing the firmware in the board using OpenOCD
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. code-block:: shell
@@ -137,16 +174,129 @@ Reset the board and using the 'NSH>' terminal start the LVGL demo:
nsh> lvgldemo
Custom Usage
************
The example app called ``lvgldemo`` uses LVGL's NuttX integration
to run the demos in NuttX.
https://github.com/apache/nuttx-apps/tree/master/examples/lvgldemo
It is used by all LVGL defconfigs. See ``sim:lvgl_fb`` and ``sim:lvgl_lcd``.
You can use it as a reference for adding LVGL to your own NuttX app.
Start by copying the contents of ``lvgldemo.c``. It handles fb and lcd based
display drivers, the touchscreen input driver, and libuv.
NuttX Driver Support
********************
- **fbdev** - LVGL can create a display for ``/dev/fb*`` devices.
- **lcd** - LVGL can create a display for ``/dev/lcd*`` devices.
- **input/uinput touchscreen** - LVGL can create an indev(s) for
touch devices that use the NuttX input/uinput system.
- **libuv** - LVGL has support for using libuv as its event loop manager.
libuv apps can integrate seamlessly.
There is no support for input/uinput keyboards yet. The NuttX X11 sim
keyboard driver emits keycodes that are not standard so the LVGL integration
with it would not be generic, if it were added.
Other Integrations
******************
- LVGL+NuttX profiler integration
- Optional dedicated image cache heap
Configurations
--------------
**************
The LVGL library is a NuttX "app". You can configure LVGL in ``menuconfig``.
.. code-block:: shell
$ ./tools/configure.sh stm32f429i-disco:lvgl
$ make menuconfig
The LVGL `Kconfig`
file provides the available config options to the NuttX build system. The LVGL configs in
``menuconfig`` can be found under
**Application Configuration > Graphics Support > Light and Versatile Graphic Library (LVGL) > LVGL configuration**.
To find the location of a specific config, Press the "/" key to open a search interface.
Here are some configurations that you can use to customize your NuttX and LVGL setup:
- **LV_USE_NUTTX_INDEPENDENT_IMAGE_HEAP** - You can enable or disable the
LVGL image heap in NuttX. By default, it is disabled. If you enable
it, LVGL will use the NuttX heap instead.
Using :c:macro:`LV_STDLIB_CLIB` for :c:macro:`LV_USE_STDLIB_MALLOC`,
:c:macro:`LV_USE_STDLIB_STRING`, or :c:macro:`LV_USE_STDLIB_SPRINTF` is
reasonable as NuttX fully implements these standard library APIs. Whether or
not you choose to use NuttX's ``malloc`` depends on whether you want LVGL
to allocate from the NuttX global heap or use its own.
Where is ``LV_OS_NUTTX``?
-------------------------
NuttX tries to be POSIX compliant where possible, meaning it supports
pthreads (POSIX threads). To enable OS features in LVGL on NuttX,
set :c:macro:`LV_USE_OS` to :c:macro:`LV_OS_PTHREAD`.
The main reason for enabling OS features is for multi-core rendering.
See :c:macro:`LV_DRAW_SW_DRAW_UNIT_CNT`. Otherwise there is no case
for setting it.
Using a Specific Version of LVGL
********************************
Here are the steps to use the latest (or any) version of LVGL in NuttX.
First ensure the build artifacts have been cleared. It will remove the existing unpacked LVGL and ZIP
if there is one.
.. code-block:: shell
$ make distclean
Now you can ``git clone`` the latest LVGL into the NuttX apps tree. It will persist even after ``make distclean``
because the build system will not remove lvgl if it is a Git repo.
.. code-block:: shell
$ cd /path/to/nuttxspace/apps/graphics/lvgl
$ git clone https://github.com/lvgl/lvgl.git
Finally, you must copy the content of ``apps/graphics/lvgl/lvgl/Kconfig`` into
the middle of ``apps/graphics/lvgl/Kconfig``. See the "PASTE THE CONTENTS ..." section below.
``apps/graphics/lvgl/Kconfig``:
.. code-block::
#
# For a description of the syntax of this configuration file,
# see the file kconfig-language.txt in the NuttX tools repository.
#
menuconfig GRAPHICS_LVGL
bool "Light and Versatile Graphic Library (LVGL)"
default n
---help---
Enable support for the LVGL GUI library.
if GRAPHICS_LVGL
(PASTE THE CONTENTS OF apps/graphics/lvgl/lvgl/Kconfig HERE)
config LV_OPTLEVEL
string "Customize compilation optimization level"
default ""
endif # GRAPHICS_LVGL
Where can I find more information?
----------------------------------
**********************************
- This blog post: `LVGL on
LPCXpresso54628 <https://acassis.wordpress.com/2018/07/19/running-nuttx-on-lpcxpresso54628-om13098/>`__