Update contrib.rst

Author: earlephilhower

docs/contrib.rst

@@ -36,6 +36,14 @@ track of them when release messages are generated.
 Adding a New Board
 ------------------
 
+Adding a new board requires:
+
+* Updated ``tools/makeboards.py`` script
+* Updated ``boards.txt`` file, generated by ``makeboard.py``
+* Updated ``package_pico_index.template.json`` file, generated by  ``makeboard.py``
+* New ``tools/json/BOARD_NAME.json`` board file for Platform.IO
+* New ``variants/BOARD_NAME/pins_arduino.h`` header defining the I/O pins
+
 To add a new RP2040 board you will need to update the ``tools/makeboards.py``
 script.  Do *NOT* manually edit ``boards.txt``, that file is machine generated.
 You will need to add a ``MakeBoard`` call at the end of the file.  Please be sure
@@ -45,10 +53,16 @@ and then the board name.  Otherwise it is hard to find a specific board in the m
 Run ``python3 tools/makeboards.py`` to update the ``boards.txt`` file and generate
 a Platform.IO JSON file in the ``tools/json`` directory.
 
+Create a folder called ``variants/BOARD_NAME`` and place in a ``pins_arduino.h``
+file in it that contains your default pin name mapping (i.e. SPI0/1 pins, UART
+pins, LED_DEFAULT, etc.).  Copying one of the existing ones as a template can
+make this task much simpler.
+
 In your ``git commit`` be sure to add the newly generated ``tools/json/XXX.json``
-file as well as the modified ``makeboards`` script and ``boards.txt`` and the
-Arduino packaging JSON ``package/package_pico_index.template.json``.  You should
-also add a note in the ``README.md`` file listing your new board.
+file as well as the modified ``makeboards`` script and ``boards.txt``, the new
+``pins_arduino.h`` header you generated, and the Arduino packaging JSON
+``package/package_pico_index.template.json``.  You should also add a note in
+the ``README.md`` file listing your new board.
 
 Submit the updated commit as a PR and, if all goes well, your board will be in
 on the next core release.