docs: port getting started doc to rst

Signed-off-by: perigoso <perigoso@riseup.net>

docs/reference/getting_started.rst

@@ -0,0 +1,153 @@
+***************
+Getting Started
+***************
+
+Add TinyUSB to your project
+---------------------------
+
+It is relatively simple to incorporate tinyusb to your (existing) project
+
+
+* Copy or ``git submodule`` this repo into your project in a subfolder. Let's say it is *your_project/tinyusb*
+* Add all the .c in the ``tinyusb/src`` folder to your project
+* Add *your_project/tinyusb/src* to your include path. Also make sure your current include path also contains the configuration file tusb_config.h.
+* Make sure all required macros are all defined properly in tusb_config.h (configure file in demo application is sufficient, but you need to add a few more such as CFG_TUSB_MCU, CFG_TUSB_OS since they are passed by IDE/compiler to maintain a unique configure for all boards).
+* If you use the device stack, make sure you have created/modified usb descriptors for your own need. Ultimately you need to implement all **tud descriptor** callbacks for the stack to work.
+* Add tusb_init() call to your reset initialization code.
+* Call ``tud_int_handler()`` (device) and/or ``tuh_int_handler()`` (host) in your USB IRQ Handler
+* Implement all enabled classes's callbacks.
+* If you don't use any RTOSes at all, you need to continuously and/or periodically call tud_task()/tuh_task() function. All of the callbacks and functionality are handled and invoked within the call of that task runner.
+
+.. code-block::
+
+   int main(void)
+   {
+     your_init_code();
+     tusb_init(); // initialize tinyusb stack
+
+     while(1) // the mainloop
+     {
+       your_application_code();
+
+       tud_task(); // device task
+       tuh_task(); // host task
+     }
+   }
+
+Examples
+--------
+
+For your convenience, TinyUSB contains a handful of examples for both host and device with/without RTOS to quickly test the functionality as well as demonstrate how API() should be used. Most examples will work on most of `the supported Boards <boards.md>`_. Firstly we need to ``git clone`` if not already
+
+.. code-block::
+
+   $ git clone https://github.com/hathach/tinyusb tinyusb
+   $ cd tinyusb
+
+Some TinyUSB examples also requires external submodule libraries in ``/lib`` such as FreeRTOS, Lightweight IP to build. Run following command to fetch them 
+
+.. code-block::
+
+   $ git submodule update --init lib
+
+In addition, MCU driver submodule is also needed to provide low-level MCU peripheral's driver. Luckily, it will be fetched if needed when you run the ``make`` to build your board.
+
+Note: some examples especially those that uses Vendor class (e.g webUSB) may requires udev permission on Linux (and/or macOS) to access usb device. It depends on your OS distro, typically copy ``/examples/device/99-tinyusb.rules`` file to /etc/udev/rules.d/ then run ``sudo udevadm control --reload-rules && sudo udevadm trigger`` is good enough.
+
+Build
+^^^^^
+
+To build example, first change directory to an example folder. 
+
+.. code-block::
+
+   $ cd examples/device/cdc_msc
+
+Then compile with ``make BOARD=[board_name] all``\ , for example
+
+.. code-block::
+
+   $ make BOARD=feather_nrf52840_express all
+
+Note: ``BOARD`` can be found as directory name in ``hw/bsp``\ , either in its family/boards or directly under bsp (no family).
+
+Port Selection
+~~~~~~~~~~~~~~
+
+If a board has several ports, one port is chosen by default in the individual board.mk file. Use option ``PORT=x`` To choose another port. For example to select the HS port of a STM32F746Disco board, use:
+
+.. code-block::
+
+   $ make BOARD=stm32f746disco PORT=1 all
+
+Port Speed
+~~~~~~~~~~
+
+A MCU can support multiple operational speed. By default, the example build system will use the fastest supported on the board. Use option ``SPEED=full/high`` e.g To force F723 operate at full instead of default high speed
+
+.. code-block::
+
+   $ make BOARD=stm32f746disco SPEED=full all
+
+Debug
+^^^^^
+
+To compile for debugging add ``DEBUG=1``\ , for example
+
+.. code-block::
+
+   $ make BOARD=feather_nrf52840_express DEBUG=1 all
+
+Log
+~~~
+
+Should you have an issue running example and/or submitting an bug report. You could enable TinyUSB built-in debug logging with optional ``LOG=``. LOG=1 will only print out error message, LOG=2 print more information with on-going events. LOG=3 or higher is not used yet. 
+
+.. code-block::
+
+   $ make BOARD=feather_nrf52840_express LOG=2 all
+
+Logger
+~~~~~~
+
+By default log message is printed via on-board UART which is slow and take lots of CPU time comparing to USB speed. If your board support on-board/external debugger, it would be more efficient to use it for logging. There are 2 protocols: 
+
+
+* `LOGGER=rtt`: use [Segger RTT protocol](https://www.segger.com/products/debug-probes/j-link/technology/about-real-time-transfer/)   
+
+  * Cons: requires jlink as the debugger.
+  * Pros: work with most if not all MCUs
+  * Software viewer is JLink RTT Viewer/Client/Logger which is bundled with JLink driver package.
+
+* ``LOGGER=swo``\ : Use dedicated SWO pin of ARM Cortex SWD debug header.
+
+  * Cons: only work with ARM Cortex MCUs minus M0
+  * Pros: should be compatible with more debugger that support SWO.
+  * Software viewer should be provided along with your debugger driver.
+
+.. code-block::
+
+   $ make BOARD=feather_nrf52840_express LOG=2 LOGGER=rtt all
+   $ make BOARD=feather_nrf52840_express LOG=2 LOGGER=swo all
+
+Flash
+^^^^^
+
+``flash`` target will use the default on-board debugger (jlink/cmsisdap/stlink/dfu) to flash the binary, please install those support software in advance. Some board use bootloader/DFU via serial which is required to pass to make command
+
+.. code-block::
+
+   $ make BOARD=feather_nrf52840_express flash
+   $ make SERIAL=/dev/ttyACM0 BOARD=feather_nrf52840_express flash
+
+Since jlink can be used with most of the boards, there is also ``flash-jlink`` target for your convenience.
+
+.. code-block::
+
+   $ make BOARD=feather_nrf52840_express flash-jlink
+
+Some board use uf2 bootloader for drag & drop in to mass storage device, uf2 can be generated with ``uf2`` target
+
+.. code-block::
+
+   $ make BOARD=feather_nrf52840_express all uf2