# Matrix Keypad

    identifier: 0x13062dc8
    extends: _sensor
    group: button
    status: experimental

A matrix of buttons connected as a keypad

## Registers

    ro pressed @ reading {
        repeats:
          index: u8
    }

The coordinate of the button currently pressed. Keys are zero-indexed from left to right, top to bottom:
``row = index / columns``, ``column = index % columns``.

    const rows: u8 # @ 0x180

Number of rows in the matrix

    const columns: u8 # @ 0x181

Number of columns in the matrix

    const labels? @ 0x182 {
        repeats:
            label: string0
    }

The characters printed on the keys if any, in indexing sequence.

    enum Variant: u8 {
        Membrane = 1
        Keyboard = 2
        Elastomer = 3
        ElastomerLEDPixel = 4
    }
    const variant?: Variant @ variant

The type of physical keypad. If the variant is ``ElastomerLEDPixel``
and the next service on the device is a ``LEDPixel`` service, it is considered
as the service controlling the LED pixel on the keypad.
## Events

    event down: u8 @ active

Emitted when a key, at the given index, goes from inactive (`pressed == 0`) to active.

    event up: u8 @ inactive

Emitted when a key, at the given index, goes from active (`pressed == 1`) to inactive.

    event click: u8 @ 0x80

Emitted together with `up` when the press time was not longer than 500ms.

    event long_click: u8 @ 0x81

Emitted together with `up` when the press time was more than 500ms.