When you finish this tutorial you will be able to be able to modify a multi-layer keybrd sketch to suite your own multi-layer keyboard design.
layers are key bindings provided by the keyboard firmware. For example,
layer code - is an integer used to identify a layer.
active layer - is the layer currently used by the keyboard.
layer scheme - is a system for changing layers while typing (a single-layer scheme does not change layers).
The following pseudo code has just enough detail to show how layer schemes work.
Layer objects select the active layer. When a Layer object is pressed, it tells StateLayer to update the active layer. There is one Key_Layer object for each layer. Each Key_Layer object has a unique layer Id number.
class Key_Layer
{
int layer
StateLayer& refStateLayer
press() { refStateLayer.setLayer(layer) }
}
A StateLayer’s activeLayer is always up to date.
class StateLayer
{
int activeLayer
setActiveLayer(int layer) { activeLayer = layer }
getActiveLayer() { return activeLayer }
}
Layered objects contain an array of Key pointers, one Key pointer for each layer. Layer Id numbers are used as array indexes in the Key_Layered ptrsKeys array. When a Layered object is pressed, it gets the active layer from StateLayer, and then presses the key of the active layer.
class Key_Layered
{
Key** ptrsKeys //array of Key pointers, one Key pointer per layer
StateLayer& refStateLayer
press() { layer = refStateLayer.getActiveLayer()
ptrsKeys[layer]->press() }
}
Dependency diagram
+-----------+
| Key_Layer |
+-----------+
|
|setLayer()
|
v
+------------+
| StateLayer |
+------------+
^
|
|getLayer()
|
+-------------+
| Key_Layered |
+-------------+
There are several layer scheme-classes to choose from. You can view all the class definitions in the keybrd library.
Layer classes include:
There is only one StateLayer class:
Layered classes include:
Most Code objects only have one scancode or code. They are not affected by the active layer. Example single-layer Code classes include:
(Future version of keybrd library may change all Code classes to Key classes.)
The keybrd_3a_multi-layer_annotated.ino sketch uses three layer-scheme classes:
Annotations in the sketch explain how the multi-layer feature works.
1) Modify the keybrd_3_multi-layer_annotated.ino sketch to use two Code_LayerLock objects.
Layout | 0 | 1 |
---|---|---|
0 | a 1 | b 2 |
1 | layer0 | layer1 |
keybrd tutorial by Wolfram Volpi is licensed under a Creative Commons Attribution 4.0 International License.
Permissions beyond the scope of this license may be available at https://github.com/wolfv6/keybrd/issues/new.