Keyboard Scan
Overview
The kscan driver (keyboard scan matrix) is used for detecting a key press in a connected matrix keyboard or any device with buttons such as joysticks. Typically, matrix keyboards are implemented using a two-dimensional configuration in order to sense several keys. This allows interfacing to many keys through fewer physical pins. Keyboard matrix drivers read the rows while applying power through the columns one at a time with the purpose of detecting key events. There is no correlation between the physical and electrical layout of keys. For, example, the physical layout may be one array of 16 or fewer keys, which may be electrically connected to a 4 x 4 array. In addition, key values are defined by a keymap provided by the keyboard manufacturer.
Configuration Options
Related configuration options:
API Reference
- group kscan_interface
KSCAN APIs.
Typedefs
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typedef void (*kscan_callback_t)(const struct device *dev, uint32_t row, uint32_t column, bool pressed)
Keyboard scan callback called when user press/release a key on a matrix keyboard.
- Param dev:
Pointer to the device structure for the driver instance.
- Param row:
Describes row change.
- Param column:
Describes column change.
- Param pressed:
Describes the kind of key event.
Functions
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int kscan_config(const struct device *dev, kscan_callback_t callback)
Configure a Keyboard scan instance.
- Parameters:
dev – Pointer to the device structure for the driver instance.
callback – called when keyboard devices reply to to a keyboard event such as key pressed/released.
- Return values:
0 – If successful.
Negative – errno code if failure.
-
typedef void (*kscan_callback_t)(const struct device *dev, uint32_t row, uint32_t column, bool pressed)