* Improve backlight PWM pin support
* I accidentally an equals sign
* Another typo
* Order by pin number
* Throw an error if backlight pin is C4 or C5 on 16/32U4
* Use else for clarity
* Minor alignment adjustments
@ -30,32 +30,31 @@ You should then be able to use the keycodes below to change the backlight level.
This feature is distinct from both the [RGB underglow](feature_rgblight.md) and [RGB matrix](feature_rgb_matrix.md) features as it usually allows for only a single colour per switch, though you can obviously use multiple different coloured LEDs on a keyboard.
Hardware PWM is only supported on certain pins of the MCU, so if the backlighting is not connected to one of them, a software PWM implementation triggered by hardware timer interrupts will be used.
Hardware PWM is supported according to the following table:
| Backlight Pin | Hardware timer |
|---------------|-------------------------|
|`B5` | Timer 1 |
|`B6` | Timer 1 |
|`B7` | Timer 1 |
|`C6` | Timer 3 |
|`D4` | Timer 1 (ATmega32A only)|
| other | Software PWM |
The [audio feature](feature_audio.md) also uses hardware timers. Please refer to the following table to know what hardware timer the software PWM will use depending on the audio configuration:
When all timers are in use for [audio](feature_audio.md), the backlight software PWM will not use a hardware timer, but instead will be triggered during the matrix scan. In this case the backlight doesn't support breathing and might show lighting artifacts (for instance flickering), because the PWM computation might not be called with enough timing precision.
All other pins will use software PWM. If the [Audio](feature_audio.md) feature is disabled or only using one timer, the backlight PWM can be triggered by a hardware timer:
|Audio Pin|Audio Timer|Software PWM Timer|
|---------|-----------|------------------|
|`C4` |Timer 3 |Timer 1 |
|`C5` |Timer 3 |Timer 1 |
|`C6` |Timer 3 |Timer 1 |
|`B5` |Timer 1 |Timer 3 |
|`B6` |Timer 1 |Timer 3 |
|`B7` |Timer 1 |Timer 3 |
When both timers are in use for Audio, the backlight PWM will not use a hardware timer, but will instead be triggered during the matrix scan. In this case, breathing is not supported, and the backlight might flicker, because the PWM computation may not be called with enough timing precision.
@ -125,7 +125,7 @@ To configure a keyboard where each switch is connected to a separate pin and gro
### Backlight Configuration
By default QMK supports backlighting on pins `B5`, `B6`, and `B7`. If you are using one of those you can simply enable it here. For more details see the [Backlight Documentation](feature_backlight.md).
QMK supports backlighting on most GPIO pins. A select few of these can be driven by the MCU in hardware. For more details see the [Backlight Documentation](feature_backlight.md).
```c
#define BACKLIGHT_PIN B7
@ -134,8 +134,6 @@ By default QMK supports backlighting on pins `B5`, `B6`, and `B7`. If you are us
#define BREATHING_PERIOD 6
```
?> You can use backlighting on any pin you like, but you will have to do more work to support that. See the [Backlight Documentation](feature_backlight.md) for more details.
### Other Configuration Options
There are a lot of features that can be configured or tuned in `config.h`. You should see the [Config Options](config_options.md) page for more details.
@ -34,7 +34,7 @@ For the `DIODE_DIRECTION`, most hand-wiring guides will instruct you to wire the
To configure a keyboard where each switch is connected to a separate pin and ground instead of sharing row and column pins, use `DIRECT_PINS`. The mapping defines the pins of each switch in rows and columns, from left to right. Must conform to the sizes within `MATRIX_ROWS` and `MATRIX_COLS`, use `NO_PIN` to fill in blank spaces. Overrides the behaviour of `DIODE_DIRECTION`, `MATRIX_ROW_PINS` and `MATRIX_COL_PINS`.
`BACKLIGHT_PIN` is the pin that your PWM-controlled backlight (if one exists) is hooked-up to. Currently only B5, B6, and B7 are supported.
`BACKLIGHT_PIN` is the pin that your PWM-controlled backlight (if one exists) is hooked-up to.
`BACKLIGHT_BREATHING` is a fancier backlight feature that adds breathing/pulsing/fading effects to the backlight. It uses the same timer as the normal backlight. These breathing effects must be called by code in your keymap.
fauxpark
5 years ago
committed by