doc updates

boards/nullbitsco/README.md

@@ -1 +1,2 @@
-https://nullbits.co/
+Mappings for [nullbits](https://nullbits.co/) keyboards,
+often based on the [BIT-C pro micro MCU](https://nullbits.co/bit-c/).

boards/nullbitsco/tidbit/README.md

@@ -1 +1,38 @@
-https://nullbits.co/tidbit/
+Keyboard mapping for the [nullbits tidbit](https://nullbits.co/tidbit/).
+
+Copy `kb.py` and `main.py` to your top level circuitpython folder beside the kmk folder.
+Edit the key mapping in `main.py` to match your build,
+for example the number and location of encoders and double-size keys.
+
+The Keyboard constructor supports a couple of optional arguments (see `kb.py`).
+
+If you're setting your tidbit up in landscape mode, 
+with the USB connector at top right instead of top left, pass 
+`landscape_layout=True`.
+
+You can specify the active encoder positions by passing a list like
+`active_encoders=[0, 2]` which corresponds to the 1st and 3rd positions shown
+in [step 6](https://github.com/nullbitsco/docs/blob/main/tidbit/build_guide_en.md#6-optional-solder-rotary-encoder-led-matrix-andor-oled-display) of the build guide.
+The default is for a single encoder in either of the top two locations labeled 1 
+in the build diagram, i.e. `active_encoders=[0]`.  Pass an empty list if you skipped
+adding any encoders.
+
+You can control the RGB backlights with the [RGB extension](http://kmkfw.io/docs/rgb).
+Here's an example:
+
+```python
+from kb import KMKKeyboard
+from kmk.extensions.rgb import RGB, AnimationModes
+
+keyboard = KMKKeyboard(active_encoders=[0], landscape_layout=True)
+
+rgb = RGB(
+    pixel_pin=keyboard.pixel_pin, 
+    num_pixels=8,
+    animation_mode=AnimationModes.BREATHING,
+    animation_speed=3,
+    breathe_center=2,
+)
+keyboard.extensions.append(rgb)
+
+```

boards/nullbitsco/tidbit/kb.py

@@ -22,7 +22,6 @@ class KMKKeyboard(_KMKKeyboard):
 
     active_encoders=[0, 2] to list installed encoder positions (first=0)
         then declare keyboard.encoders.map = [(KC.<left> , KC.<right>, None), (...)]
-    enable_rgb=False (default True) to add rgb module (requires neopixel.py)
     landscape_layout=True to orient USB port top right rather than left (default)
     """
 #    led = digitalio.DigitalInOut(board.D21)
@@ -45,7 +44,7 @@ class KMKKeyboard(_KMKKeyboard):
     diode_orientation = DiodeOrientation.ROW2COL
     i2c = board.I2C  #TODO ??
 
-    def __init__(self, active_encoders=[], landscape_layout=False):
+    def __init__(self, active_encoders=[0], landscape_layout=False):
         super().__init__()
 
         if landscape_layout: