57ba0fe8b2
- Introduce Scanner base class for MatrixScanner - Create new Scanner using built-in keypad module - Allow overriding the scanner used by KMKKeyboard
67 lines
2.1 KiB
Markdown
67 lines
2.1 KiB
Markdown
# Scanners
|
|
|
|
Smaller boards and macro pads sometimes assign a GPIO pin to each key, rather
|
|
than using a full matrix. Boards like this aren't compatible with the default
|
|
matrix scanner, so you will need to swap it out with an alternative scanner.
|
|
|
|
Beside the default `Matrix` scanner, KMK includes the following:
|
|
|
|
|
|
## keypad.Keys
|
|
|
|
The `keypad.Keys` scanner treats individual GPIO pins as discrete keys. To use
|
|
this scanner, provide a sequence of pins that describes the layout of your
|
|
board then include it in the initialisation sequence of your keyboard class.
|
|
|
|
Since the `_init_sanity_check` method in the `KMKKeyboard` class will attempt
|
|
to validate a number of settings that are no longer needed, you need to
|
|
override it with a modified version that doesn't fail when they aren't present.
|
|
|
|
|
|
```python
|
|
import board
|
|
from kmk.kmk_keyboard import KMKKeyboard
|
|
from kmk.scanners.native_keypad_scanner import keys_scanner
|
|
|
|
|
|
# GPIO to key mapping - each line is a new row.
|
|
_KEY_CFG = [
|
|
[board.SW3, board.SW7, board.SW11, board.SW15],
|
|
[board.SW2, board.SW6, board.SW10, board.SW14],
|
|
[board.SW1, board.SW5, board.SW9, board.SW13],
|
|
[board.SW0, board.SW4, board.SW8, board.SW12],
|
|
]
|
|
|
|
|
|
# Keyboard implementation class
|
|
class MyKeyboard(KMKKeyboard):
|
|
def __init__(self):
|
|
# create and register the scanner
|
|
self.matrix = keys_scanner(_KEY_CFG)
|
|
|
|
# copy the key coordinates from the scanner
|
|
self.coord_mapping = self.matrix.coord_mapping
|
|
|
|
def _init_sanity_check(self):
|
|
return self
|
|
```
|
|
|
|
|
|
## keypad.KeyMatrix
|
|
|
|
The `keypad.KeyMatrix` scanner is an alternative implementation of the default
|
|
matrix scanner using CircuitPython's builtin keypad objects. This is currently
|
|
experimental and ***not recommended for use***.
|
|
|
|
Using this scanner is similar to the `keypad.Keys` scanner. Create the scanner
|
|
using `keypad_matrix()` instead of `keys_scanner()`.
|
|
|
|
|
|
## `Scanner` base class
|
|
|
|
If you require a different type of scanner, you can create your own by
|
|
providing a subclass of `Scanner`. This is a very simple interface, it only
|
|
contains a single method, `scan_for_changes(self)` which returns a key report
|
|
if one exists, or `None` otherwise.
|
|
|