41 lines
2.2 KiB
Markdown
41 lines
2.2 KiB
Markdown
---
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title: Backlight Configuration
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sidebar_label: Backlight
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---
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See the [backlight feature page](../features/backlight.md) for more details, including instructions for adding backlight support to a board.
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See [Configuration Overview](index.md) for instructions on how to change these settings.
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## Kconfig
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Definition file: [zmk/app/Kconfig](https://github.com/zmkfirmware/zmk/blob/main/app/Kconfig)
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| Option | Type | Description | Default |
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| ------------------------------------ | ---- | ----------------------------------------------------- | ------- |
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| `CONFIG_ZMK_BACKLIGHT` | bool | Enables LED backlight | n |
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| `CONFIG_ZMK_BACKLIGHT_BRT_STEP` | int | Brightness step in percent | 20 |
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| `CONFIG_ZMK_BACKLIGHT_BRT_START` | int | Default brightness in percent | 40 |
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| `CONFIG_ZMK_BACKLIGHT_ON_START` | bool | Default backlight state | y |
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| `CONFIG_ZMK_BACKLIGHT_AUTO_OFF_IDLE` | bool | Turn off backlight when keyboard goes into idle state | n |
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| `CONFIG_ZMK_BACKLIGHT_AUTO_OFF_USB` | bool | Turn off backlight when USB is disconnected | n |
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:::note
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The `*_START` settings only determine the initial backlight state. Any changes you make with the [backlight behavior](../behaviors/backlight.md) are saved to flash after a one minute delay and will be used after that.
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:::
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## Devicetree
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Applies to: [`/chosen` node](https://docs.zephyrproject.org/latest/build/dts/intro.html#aliases-and-chosen-nodes)
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| Property | Type | Description |
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| --------------- | ---- | -------------------------------------------- |
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| `zmk,backlight` | path | The node for the backlight LED driver to use |
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See the Zephyr devicetree bindings for LED drivers:
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- [gpio-leds](https://docs.zephyrproject.org/latest/build/dts/api/bindings/gpio/gpio-leds.html)
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- [pwm-leds](https://docs.zephyrproject.org/latest/build/dts/api/bindings/led/pwm-leds.html)
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See the [backlight feature page](../features/backlight.md) for examples of the properties that must be set to enable backlighting.
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