diff --git a/docs/feature_backlight.md b/docs/feature_backlight.md index 24057c608f..d032c33f18 100644 --- a/docs/feature_backlight.md +++ b/docs/feature_backlight.md @@ -1,12 +1,12 @@ # Backlighting :id=backlighting -Many keyboards support backlit keys by way of individual LEDs placed through or underneath the keyswitches. 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 install multiple different single coloured LEDs on a keyboard. +Many keyboards support backlit keys by way of individual LEDs placed through or underneath the keyswitches. 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 install multiple different single coloured LEDs on a keyboard. QMK is able to control the brightness of these LEDs by switching them on and off rapidly in a certain ratio, a technique known as *Pulse Width Modulation*, or PWM. By altering the duty cycle of the PWM signal, it creates the illusion of dimming. -The MCU can only supply so much current to its GPIO pins. Instead of powering the backlight directly from the MCU, the backlight pin is connected to a transistor or MOSFET that switches the power to the LEDs. +## Usage :id=usage -Most keyboards have backlighting enabled by default if they support it, but if it is not working for you, check that your `rules.mk` includes the following: +Most keyboards have backlighting enabled by default if they support it, but if it is not working for you (or you have added support), check that your `rules.mk` includes the following: ```make BACKLIGHT_ENABLE = yes @@ -14,57 +14,23 @@ BACKLIGHT_ENABLE = yes ## Keycodes :id=keycodes -Once enabled, the following keycodes below can be used to change the backlight level. +|Key |Aliases |Description | +|-------------------------------|---------|-----------------------------------| +|`QK_BACKLIGHT_TOGGLE` |`BL_TOGG`|Turn the backlight on or off | +|`QK_BACKLIGHT_STEP` |`BL_STEP`|Cycle through backlight levels | +|`QK_BACKLIGHT_ON` |`BL_ON` |Set the backlight to max brightness| +|`QK_BACKLIGHT_OFF` |`BL_OFF` |Turn the backlight off | +|`QK_BACKLIGHT_UP` |`BL_UP` |Increase the backlight level | +|`QK_BACKLIGHT_DOWN` |`BL_DOWN`|Decrease the backlight level | +|`QK_BACKLIGHT_TOGGLE_BREATHING`|`BL_BRTG`|Toggle backlight breathing | -| Key | Aliases | Description | -|---------------------------------|-----------|-------------------------------------| -| `QK_BACKLIGHT_TOGGLE` | `BL_TOGG` | Turn the backlight on or off | -| `QK_BACKLIGHT_STEP` | `BL_STEP` | Cycle through backlight levels | -| `QK_BACKLIGHT_ON` | `BL_ON` | Set the backlight to max brightness | -| `QK_BACKLIGHT_OFF` | `BL_OFF` | Turn the backlight off | -| `QK_BACKLIGHT_UP` | `BL_UP` | Increase the backlight level | -| `QK_BACKLIGHT_DOWN` | `BL_DOWN` | Decrease the backlight level | -| `QK_BACKLIGHT_TOGGLE_BREATHING` | `BL_BRTG` | Toggle backlight breathing | +## Basic Configuration :id=basic-configuration -## Functions :id=functions - -These functions can be used to change the backlighting in custom code: - -|Function |Description | -|------------------------|--------------------------------------------| -|`backlight_toggle()` |Turn the backlight on or off | -|`backlight_enable()` |Turn the backlight on | -|`backlight_disable()` |Turn the backlight off | -|`backlight_step()` |Cycle through backlight levels | -|`backlight_increase()` |Increase the backlight level | -|`backlight_decrease()` |Decrease the backlight level | -|`backlight_level(x)` |Sets the backlight level to specified level | -|`get_backlight_level()` |Return the current backlight level | -|`is_backlight_enabled()`|Return whether the backlight is currently on| - -If backlight breathing is enabled (see below), the following functions are also available: - -|Function |Description | -|---------------------|--------------------------------------| -|`breathing_toggle()` |Turn the backlight breathing on or off| -|`breathing_enable()` |Turns on backlight breathing | -|`breathing_disable()`|Turns off backlight breathing | - -## Configuration :id=configuration - -To select which driver to use, configure your `rules.mk` with the following: - -```make -BACKLIGHT_DRIVER = software -``` - -Valid driver values are `pwm`, `software`, `custom` or `no`. See below for help on individual drivers. - -To configure the backlighting, `#define` these in your `config.h`: +Add the following to your `config.h`: |Define |Default |Description | |-----------------------------|------------------|-----------------------------------------------------------------------------------------------------------------| -|`BACKLIGHT_PIN` |*Not defined* |The pin that controls the LED(s) | +|`BACKLIGHT_PIN` |*Not defined* |The pin that controls the LEDs | |`BACKLIGHT_LEVELS` |`3` |The number of brightness levels (maximum 31 excluding off) | |`BACKLIGHT_CAPS_LOCK` |*Not defined* |Enable Caps Lock indicator using backlight (for keyboards without dedicated LED) | |`BACKLIGHT_BREATHING` |*Not defined* |Enable backlight breathing, if supported | @@ -76,124 +42,66 @@ To configure the backlighting, `#define` these in your `config.h`: Unless you are designing your own keyboard, you generally should not need to change the `BACKLIGHT_PIN` or `BACKLIGHT_ON_STATE`. -### Backlight On State :id=backlight-on-state +### "On" State :id=on-state Most backlight circuits are driven by an N-channel MOSFET or NPN transistor. This means that to turn the transistor *on* and light the LEDs, you must drive the backlight pin, connected to the gate or base, *high*. Sometimes, however, a P-channel MOSFET, or a PNP transistor is used. In this case, when the transistor is on, the pin is driven *low* instead. -This functionality is configured at the keyboard level with the `BACKLIGHT_ON_STATE` define. +To configure the "on" state of the backlight circuit, add the following to your `config.h`: -### AVR Driver :id=avr-driver - -The `pwm` driver is configured by default, however the equivalent setting within `rules.mk` would be: - -```make -BACKLIGHT_DRIVER = pwm +```c +#define BACKLIGHT_ON_STATE 0 ``` -#### Caveats :id=avr-caveats - -On AVR boards, QMK automatically decides which driver to use according to the following table: - -|Backlight Pin|AT90USB64/128|AT90USB162|ATmega16/32U4|ATmega16/32U2|ATmega32A|ATmega328/P| -|-------------|-------------|----------|-------------|-------------|---------|-----------| -|`B1` | | | | | |Timer 1 | -|`B2` | | | | | |Timer 1 | -|`B5` |Timer 1 | |Timer 1 | | | | -|`B6` |Timer 1 | |Timer 1 | | | | -|`B7` |Timer 1 |Timer 1 |Timer 1 |Timer 1 | | | -|`C4` |Timer 3 | | | | | | -|`C5` |Timer 3 |Timer 1 | |Timer 1 | | | -|`C6` |Timer 3 |Timer 1 |Timer 3 |Timer 1 | | | -|`D4` | | | | |Timer 1 | | -|`D5` | | | | |Timer 1 | | - -All other pins will use timer-assisted software PWM: - -|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 cannot use a hardware timer, and 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. - -#### Hardware PWM Implementation :id=hardware-pwm-implementation - -When using the supported pins for backlighting, QMK will use a hardware timer configured to output a PWM signal. This timer will count up to `ICRx` (by default `0xFFFF`) before resetting to 0. -The desired brightness is calculated and stored in the `OCRxx` register. When the counter reaches this value, the backlight pin will go low, and is pulled high again when the counter resets. -In this way `OCRxx` essentially controls the duty cycle of the LEDs, and thus the brightness, where `0x0000` is completely off and `0xFFFF` is completely on. - -The breathing effect is achieved by registering an interrupt handler for `TIMER1_OVF_vect` that is called whenever the counter resets, roughly 244 times per second. -In this handler, the value of an incrementing counter is mapped onto a precomputed brightness curve. To turn off breathing, the interrupt handler is simply disabled, and the brightness reset to the level stored in EEPROM. - -#### Timer Assisted PWM Implementation :id=timer-assisted-implementation - -When `BACKLIGHT_PIN` is not set to a hardware backlight pin, QMK will use a hardware timer configured to trigger software interrupts. This time will count up to `ICRx` (by default `0xFFFF`) before resetting to 0. -When resetting to 0, the CPU will fire an OVF (overflow) interrupt that will turn the LEDs on, starting the duty cycle. -The desired brightness is calculated and stored in the `OCRxx` register. When the counter reaches this value, the CPU will fire a Compare Output match interrupt, which will turn the LEDs off. -In this way `OCRxx` essentially controls the duty cycle of the LEDs, and thus the brightness, where `0x0000` is completely off and `0xFFFF` is completely on. - -The breathing effect is the same as in the hardware PWM implementation. - -### ARM Driver :id=arm-configuration - -While still in its early stages, ARM backlight support aims to eventually have feature parity with AVR. The `pwm` driver is configured by default, however the equivalent setting within `rules.mk` would be: - -```make -BACKLIGHT_DRIVER = pwm -``` - -#### ChibiOS Configuration :id=arm-configuration - -The following `#define`s apply only to ARM-based keyboards: - -|Define |Default|Description | -|-----------------------|-------|-----------------------------------| -|`BACKLIGHT_PWM_DRIVER` |`PWMD4`|The PWM driver to use | -|`BACKLIGHT_PWM_CHANNEL`|`3` |The PWM channel to use | -|`BACKLIGHT_PAL_MODE` |`2` |The pin alternative function to use| - -See the ST datasheet for your particular MCU to determine these values. Unless you are designing your own keyboard, you generally should not need to change them. - -#### Caveats :id=arm-caveats - -Currently only hardware PWM is supported, not timer assisted, and does not provide automatic configuration. - -### Software PWM Driver :id=software-pwm-driver - -In this mode, PWM is "emulated" while running other keyboard tasks. It offers maximum hardware compatibility without extra platform configuration. The tradeoff is the backlight might jitter when the keyboard is busy. To enable, add this to your `rules.mk`: - -```make -BACKLIGHT_DRIVER = software -``` - -#### Multiple Backlight Pins :id=multiple-backlight-pins +### Multiple Backlight Pins :id=multiple-backlight-pins Most keyboards have only one backlight pin which controls all backlight LEDs (especially if the backlight is connected to a hardware PWM pin). -In software PWM, it is possible to define multiple backlight pins, which will be turned on and off at the same time during the PWM duty cycle. +The `timer` and `software` drivers allow you to define multiple backlight pins, which will be turned on and off at the same time during the PWM duty cycle. This feature allows to set, for instance, the Caps Lock LED's (or any other controllable LED) brightness at the same level as the other LEDs of the backlight. This is useful if you have mapped Control in place of Caps Lock and you need the Caps Lock LED to be part of the backlight instead of being activated when Caps Lock is on, as it is usually wired to a separate pin from the backlight. -To activate multiple backlight pins, add something like this to your `config.h`, instead of `BACKLIGHT_PIN`: +To configure multiple backlight pins, add something like this to your `config.h`, instead of `BACKLIGHT_PIN`: ```c #define BACKLIGHT_PINS { F5, B2 } ``` +## Driver Configuration :id=driver-configuration + +Backlight driver selection is configured in `rules.mk`. Valid drivers are `pwm` (default), `timer`, `software`, or `custom`. See below for information on individual drivers. + +### PWM Driver :id=pwm-driver + +This is the default backlight driver, which leverages the hardware PWM output capability of the microcontroller. + +```make +BACKLIGHT_DRIVER = pwm +``` + +### Timer Driver :id=timer-driver + +This driver is similar to the PWM driver, but instead of directly configuring the pin to output a PWM signal, an interrupt handler is attached to the timer to turn the pin on and off as appropriate. + +```make +BACKLIGHT_DRIVER = timer +``` + +### Software Driver :id=software-driver + +In this mode, PWM is "emulated" while running other keyboard tasks. It offers maximum hardware compatibility without extra platform configuration. However, breathing is not supported, and the backlight can flicker when the keyboard is busy. + +```make +BACKLIGHT_DRIVER = software +``` + ### Custom Driver :id=custom-driver -If none of the above drivers apply to your board (for example, you are using a separate IC to control the backlight), you can implement a custom backlight driver using this simple API provided by QMK. To enable, add this to your `rules.mk`: +If none of the above drivers apply to your board (for example, you are using a separate IC to control the backlight), you can implement a custom backlight driver using a simple API. ```make BACKLIGHT_DRIVER = custom ``` -Then implement any of these hooks: - ```c void backlight_init_ports(void) { // Optional - runs on startup @@ -211,10 +119,188 @@ void backlight_task(void) { } ``` +## AVR Configuration :id=avr-configuration + +### PWM Driver :id=avr-pwm-driver + +The following table describes the supported pins for the PWM driver. Only cells marked with a timer number are capable of hardware PWM output; any others must use the `timer` driver. + +|Backlight Pin|AT90USB64/128|AT90USB162|ATmega16/32U4|ATmega16/32U2|ATmega32A|ATmega328/P| +|-------------|-------------|----------|-------------|-------------|---------|-----------| +|`B1` | | | | | |Timer 1 | +|`B2` | | | | | |Timer 1 | +|`B5` |Timer 1 | |Timer 1 | | | | +|`B6` |Timer 1 | |Timer 1 | | | | +|`B7` |Timer 1 |Timer 1 |Timer 1 |Timer 1 | | | +|`C4` |Timer 3 | | | | | | +|`C5` |Timer 3 |Timer 1 | |Timer 1 | | | +|`C6` |Timer 3 |Timer 1 |Timer 3 |Timer 1 | | | +|`D4` | | | | |Timer 1 | | +|`D5` | | | | |Timer 1 | | + +### Timer Driver :id=avr-timer-driver + +Any GPIO pin can be used with this driver. The following table describes the supported timers: + +|AT90USB64/128|AT90USB162|ATmega16/32U4|ATmega16/32U2|ATmega32A|ATmega328/P| +|-------------|----------|-------------|-------------|---------|-----------| +|Timers 1 & 3 |Timer 1 |Timers 1 & 3 |Timer 1 |Timer 1 |Timer 1 | + +The following `#define`s apply only to the `timer` driver: + +|Define |Default|Description | +|-----------------------|-------|----------------| +|`BACKLIGHT_PWM_TIMER` |`1` |The timer to use| + +Note that the choice of timer may conflict with the [Audio](feature_audio.md) feature. + +## ChibiOS/ARM Configuration :id=arm-configuration + +### PWM Driver :id=arm-pwm-driver + +Depending on the ChibiOS board configuration, you may need to enable PWM at the keyboard level. For STM32, this would look like: + +`halconf.h`: +```c +#define HAL_USE_PWM TRUE +``` +`mcuconf.h`: +```c +#undef STM32_PWM_USE_TIM4 +#define STM32_PWM_USE_TIM4 TRUE +``` + +The following `#define`s apply only to the `pwm` driver: + +|Define |Default |Description | +|-----------------------|--------|-----------------------------------| +|`BACKLIGHT_PWM_DRIVER` |`PWMD4` |The PWM driver to use | +|`BACKLIGHT_PWM_CHANNEL`|`3` |The PWM channel to use | +|`BACKLIGHT_PAL_MODE` |`2` |The pin alternative function to use| + +Refer to the ST datasheet for your particular MCU to determine these values. For example, these defaults are set up for pin `B8` on a Proton-C (STM32F303) using `TIM4_CH3` on AF2. Unless you are designing your own keyboard, you generally should not need to change them. + +### Timer Driver :id=arm-timer-driver + +Depending on the ChibiOS board configuration, you may need to enable general-purpose timers at the keyboard level. For STM32, this would look like: + +`halconf.h`: +```c +#define HAL_USE_GPT TRUE +``` +`mcuconf.h`: +```c +#undef STM32_GPT_USE_TIM15 +#define STM32_GPT_USE_TIM15 TRUE +``` + +The following `#define`s apply only to the `timer` driver: + +|Define |Default |Description | +|----------------------|--------|----------------| +|`BACKLIGHT_GPT_DRIVER`|`GPTD15`|The timer to use| + ## Example Schematic +Since the MCU can only supply so much current to its GPIO pins, instead of powering the backlight directly from the MCU, the backlight pin is connected to a transistor or MOSFET that switches the power to the LEDs. + In this typical example, the backlight LEDs are all connected in parallel towards an N-channel MOSFET. Its gate pin is wired to one of the microcontroller's GPIO pins through a 470Ω resistor to avoid ringing. A pulldown resistor is also placed between the gate pin and ground to keep it at a defined state when it is not otherwise being driven by the MCU. The values of these resistors are not critical - see [this Electronics StackExchange question](https://electronics.stackexchange.com/q/68748) for more information. ![Backlight example circuit](https://i.imgur.com/BmAvoUC.png) + +## API :id=api + +### `void backlight_toggle(void)` :id=api-backlight-toggle + +Toggle the backlight on or off. + +--- + +### `void backlight_enable(void)` :id=api-backlight-enable + +Turn the backlight on. + +--- + +### `void backlight_disable(void)` :id=api-backlight-disable + +Turn the backlight off. + +--- + +### `void backlight_step(void)` :id=api-backlight-step + +Cycle through backlight levels. + +--- + +### `void backlight_increase(void)` :id=api-backlight-increase + +Increase the backlight level. + +--- + +### `void backlight_decrease(void)` :id=api-backlight-decrease + +Decrease the backlight level. + +--- + +### `void backlight_level(uint8_t level)` :id=api-backlight-level + +Set the backlight level. + +#### Arguments :id=api-backlight-level-arguments + + - `uint8_t level` + The level to set, from 0 to `BACKLIGHT_LEVELS`. + +--- + +### `uint8_t get_backlight_level(void)` :id=api-get-backlight-level + +Get the current backlight level. + +#### Return Value :id=api-get-backlight-level-return + +The current backlight level, from 0 to `BACKLIGHT_LEVELS`. + +--- + +### `bool is_backlight_enabled(void)` :id=api-is-backlight-enabled + +Get the current backlight state. + +#### Return Value :id=api-is-backlight-enabled-return + +`true` if the backlight is enabled. + +--- + +### `void backlight_toggle_breathing(void)` :id=api-backlight-toggle-breathing + +Toggle backlight breathing on or off. + +--- + +### `void backlight_enable_breathing(void)` :id=api-backlight-enable-breathing + +Turn backlight breathing on. + +--- + +### `void backlight_disable_breathing(void)` :id=api-backlight-disable-breathing + +Turn backlight breathing off. + +--- + +### `bool is_backlight_breathing(void)` :id=api-is-backlight-breathing + +Get the current backlight breathing state. + +#### Return Value :id=api-is-backlight-breathing-return + +`true` if backlight breathing is enabled. diff --git a/keyboards/40percentclub/4pack/info.json b/keyboards/40percentclub/4pack/info.json index 9709807612..31d4559883 100644 --- a/keyboards/40percentclub/4pack/info.json +++ b/keyboards/40percentclub/4pack/info.json @@ -9,6 +9,7 @@ "device_version": "0.0.1" }, "backlight": { + "driver": "timer", "pins": ["F6", "F7"] }, "processor": "atmega32u4", diff --git a/keyboards/40percentclub/sixpack/info.json b/keyboards/40percentclub/sixpack/info.json index 3483c7d4df..cd4864fbd1 100644 --- a/keyboards/40percentclub/sixpack/info.json +++ b/keyboards/40percentclub/sixpack/info.json @@ -9,6 +9,7 @@ "device_version": "10.0.1" }, "backlight": { + "driver": "timer", "pins": ["F4", "F5"], "levels": 6, "breathing": true diff --git a/keyboards/8pack/info.json b/keyboards/8pack/info.json index fffac7d426..b572bdd0e9 100644 --- a/keyboards/8pack/info.json +++ b/keyboards/8pack/info.json @@ -8,6 +8,7 @@ "pid": "0x2171" }, "backlight": { + "driver": "timer", "pins": ["D1", "D0", "D4", "C6", "D7", "E6", "B4", "B5"], "levels": 8 }, diff --git a/keyboards/ai03/equinox/rev0/info.json b/keyboards/ai03/equinox/rev0/info.json index f5dd365564..396f50c376 100644 --- a/keyboards/ai03/equinox/rev0/info.json +++ b/keyboards/ai03/equinox/rev0/info.json @@ -5,6 +5,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D1", "levels": 5, "breathing": true diff --git a/keyboards/amjkeyboard/amj66/info.json b/keyboards/amjkeyboard/amj66/info.json index a28b91d7c6..07a170a3f6 100644 --- a/keyboards/amjkeyboard/amj66/info.json +++ b/keyboards/amjkeyboard/amj66/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D4", "breathing": true }, diff --git a/keyboards/anavi/macropad8/info.json b/keyboards/anavi/macropad8/info.json index b21f12b7d7..2ff901c0d5 100644 --- a/keyboards/anavi/macropad8/info.json +++ b/keyboards/anavi/macropad8/info.json @@ -9,6 +9,7 @@ "device_version": "0.0.1" }, "backlight": { + "driver": "timer", "pin": "D7", "breathing": true }, diff --git a/keyboards/bear_face/info.json b/keyboards/bear_face/info.json index 0c3e614803..e0df316093 100644 --- a/keyboards/bear_face/info.json +++ b/keyboards/bear_face/info.json @@ -15,6 +15,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F7" }, "processor": "atmega32u4", diff --git a/keyboards/cablecardesigns/cypher/rev6/info.json b/keyboards/cablecardesigns/cypher/rev6/info.json index 9722db7a63..5bd725322e 100644 --- a/keyboards/cablecardesigns/cypher/rev6/info.json +++ b/keyboards/cablecardesigns/cypher/rev6/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D0", "levels": 5, "breathing": true diff --git a/keyboards/cest73/tkm/info.json b/keyboards/cest73/tkm/info.json index 028e028159..6447189b93 100644 --- a/keyboards/cest73/tkm/info.json +++ b/keyboards/cest73/tkm/info.json @@ -15,6 +15,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "E6" }, "indicators": { diff --git a/keyboards/checkerboards/nop60/info.json b/keyboards/checkerboards/nop60/info.json index 8b164a9982..7dff63e711 100644 --- a/keyboards/checkerboards/nop60/info.json +++ b/keyboards/checkerboards/nop60/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D1", "levels": 6, "breathing": true diff --git a/keyboards/checkerboards/quark_plus/info.json b/keyboards/checkerboards/quark_plus/info.json index 3b8803ce71..bbe63a750b 100644 --- a/keyboards/checkerboards/quark_plus/info.json +++ b/keyboards/checkerboards/quark_plus/info.json @@ -31,6 +31,7 @@ ] }, "backlight": { + "driver": "timer", "pin": "C4", "levels": 6, "breathing": true diff --git a/keyboards/checkerboards/snop60/info.json b/keyboards/checkerboards/snop60/info.json index 00194c0184..fe9f30e289 100644 --- a/keyboards/checkerboards/snop60/info.json +++ b/keyboards/checkerboards/snop60/info.json @@ -19,6 +19,7 @@ ] }, "backlight": { + "driver": "timer", "pin": "D1", "levels": 6, "breathing": true diff --git a/keyboards/efreet/info.json b/keyboards/efreet/info.json index ea2a48be25..b7749ed341 100644 --- a/keyboards/efreet/info.json +++ b/keyboards/efreet/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D0", "breathing": true }, diff --git a/keyboards/gray_studio/cod67/info.json b/keyboards/gray_studio/cod67/info.json index 91b6668581..fa47399232 100644 --- a/keyboards/gray_studio/cod67/info.json +++ b/keyboards/gray_studio/cod67/info.json @@ -23,6 +23,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D4", "on_state": 0 }, diff --git a/keyboards/handwired/bdn9_ble/info.json b/keyboards/handwired/bdn9_ble/info.json index eb6e57abde..bb8258c7cf 100644 --- a/keyboards/handwired/bdn9_ble/info.json +++ b/keyboards/handwired/bdn9_ble/info.json @@ -9,6 +9,7 @@ "device_version": "1.0.0" }, "backlight": { + "driver": "timer", "pin": "F6", "levels": 5 }, diff --git a/keyboards/kc60se/info.json b/keyboards/kc60se/info.json index afca676446..ff9fa35165 100644 --- a/keyboards/kc60se/info.json +++ b/keyboards/kc60se/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F5", "levels": 6 }, diff --git a/keyboards/keebio/iris/rev1/info.json b/keyboards/keebio/iris/rev1/info.json index a389e7ae09..fef671c457 100644 --- a/keyboards/keebio/iris/rev1/info.json +++ b/keyboards/keebio/iris/rev1/info.json @@ -10,6 +10,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D2", "levels": 5 }, diff --git a/keyboards/kopibeng/xt65/info.json b/keyboards/kopibeng/xt65/info.json index 650e0e05b2..17e61aaf4d 100644 --- a/keyboards/kopibeng/xt65/info.json +++ b/keyboards/kopibeng/xt65/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "B1", "levels": 5 }, diff --git a/keyboards/kprepublic/cospad/info.json b/keyboards/kprepublic/cospad/info.json index 90b9dab4a1..82b6abec6c 100644 --- a/keyboards/kprepublic/cospad/info.json +++ b/keyboards/kprepublic/cospad/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F7", "on_state": 0 }, diff --git a/keyboards/ktec/daisy/info.json b/keyboards/ktec/daisy/info.json index aa9a45477a..b11e946096 100644 --- a/keyboards/ktec/daisy/info.json +++ b/keyboards/ktec/daisy/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D0", "levels": 6 }, diff --git a/keyboards/ktec/staryu/info.json b/keyboards/ktec/staryu/info.json index da277a0ae0..2235bafbb3 100644 --- a/keyboards/ktec/staryu/info.json +++ b/keyboards/ktec/staryu/info.json @@ -9,6 +9,7 @@ "device_version": "2.0.5" }, "backlight": { + "driver": "timer", "pins": ["C2", "C7", "D5", "D6", "B0"], "levels": 10 }, diff --git a/keyboards/maple_computing/christmas_tree/info.json b/keyboards/maple_computing/christmas_tree/info.json index 0a19667957..e675f2f932 100644 --- a/keyboards/maple_computing/christmas_tree/info.json +++ b/keyboards/maple_computing/christmas_tree/info.json @@ -13,6 +13,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D2" }, "processor": "atmega32u4", diff --git a/keyboards/maple_computing/ivy/rev1/info.json b/keyboards/maple_computing/ivy/rev1/info.json index 3b971cb673..de89abee75 100644 --- a/keyboards/maple_computing/ivy/rev1/info.json +++ b/keyboards/maple_computing/ivy/rev1/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D2" }, "processor": "atmega32u4", diff --git a/keyboards/maple_computing/jnao/info.json b/keyboards/maple_computing/jnao/info.json index f1e753017f..73ddf107ec 100644 --- a/keyboards/maple_computing/jnao/info.json +++ b/keyboards/maple_computing/jnao/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D0" }, "processor": "atmega32u4", diff --git a/keyboards/melgeek/mj6xy/rev3/info.json b/keyboards/melgeek/mj6xy/rev3/info.json index 3b5c7375a4..74e77035ca 100644 --- a/keyboards/melgeek/mj6xy/rev3/info.json +++ b/keyboards/melgeek/mj6xy/rev3/info.json @@ -5,7 +5,6 @@ }, "diode_direction": "COL2ROW", "backlight": { - "driver": "software", "pin": "B7", "levels": 10 }, diff --git a/keyboards/mntre/config.h b/keyboards/mntre/config.h index 55a7a8457e..c12ca23672 100644 --- a/keyboards/mntre/config.h +++ b/keyboards/mntre/config.h @@ -3,7 +3,7 @@ #pragma once -#define BACKLIGHT_CUSTOM_RESOLUTION 0x400 +#define BACKLIGHT_RESOLUTION 0x400 /* Mechanical locking support. Use KC_LCAP, KC_LNUM or KC_LSCR instead in keymap */ #define LOCKING_SUPPORT_ENABLE diff --git a/keyboards/mt/mt40/info.json b/keyboards/mt/mt40/info.json index f53e9f60d4..7b4a0cac64 100644 --- a/keyboards/mt/mt40/info.json +++ b/keyboards/mt/mt40/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D2" }, "rgblight": { diff --git a/keyboards/nopunin10did/jabberwocky/v2/info.json b/keyboards/nopunin10did/jabberwocky/v2/info.json index 71d6d94542..64848c0552 100644 --- a/keyboards/nopunin10did/jabberwocky/v2/info.json +++ b/keyboards/nopunin10did/jabberwocky/v2/info.json @@ -14,8 +14,8 @@ }, "diode_direction": "COL2ROW", "backlight": { - "driver": "software", - "pins": ["D6"], + "driver": "timer", + "pin": "D6", "levels": 6 }, "indicators": { diff --git a/keyboards/org60/info.json b/keyboards/org60/info.json index bc922012f0..c1de3084ed 100644 --- a/keyboards/org60/info.json +++ b/keyboards/org60/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F5", "levels": 6 }, diff --git a/keyboards/playkbtw/ca66/info.json b/keyboards/playkbtw/ca66/info.json index 3f9538f31c..60b17cfb46 100644 --- a/keyboards/playkbtw/ca66/info.json +++ b/keyboards/playkbtw/ca66/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F0" }, "rgblight": { diff --git a/keyboards/sandwich/keeb68/info.json b/keyboards/sandwich/keeb68/info.json index ec09badedf..df8b91a338 100644 --- a/keyboards/sandwich/keeb68/info.json +++ b/keyboards/sandwich/keeb68/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "C7", "levels": 5, "breathing": true diff --git a/keyboards/tkc/osav2/info.json b/keyboards/tkc/osav2/info.json index 7a59bb65db..c882c073ac 100644 --- a/keyboards/tkc/osav2/info.json +++ b/keyboards/tkc/osav2/info.json @@ -21,6 +21,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D6", "breathing": true }, diff --git a/keyboards/v60_type_r/info.json b/keyboards/v60_type_r/info.json index 8a2b7827ce..760a4f7356 100644 --- a/keyboards/v60_type_r/info.json +++ b/keyboards/v60_type_r/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F7", "on_state": 0 }, diff --git a/keyboards/viktus/osav2/info.json b/keyboards/viktus/osav2/info.json index eba02a4137..b528bac281 100644 --- a/keyboards/viktus/osav2/info.json +++ b/keyboards/viktus/osav2/info.json @@ -44,6 +44,7 @@ "pin": "D4" }, "backlight": { + "driver": "timer", "levels": 6, "max_brightness": 191, "pin": "D6" diff --git a/keyboards/westfoxtrot/cypher/rev5/info.json b/keyboards/westfoxtrot/cypher/rev5/info.json index c7e62632e2..6cb14f3b0e 100644 --- a/keyboards/westfoxtrot/cypher/rev5/info.json +++ b/keyboards/westfoxtrot/cypher/rev5/info.json @@ -12,6 +12,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D0", "levels": 5, "breathing": true diff --git a/keyboards/xiudi/xd60/rev2/info.json b/keyboards/xiudi/xd60/rev2/info.json index 2fae5080c3..a253f14b24 100644 --- a/keyboards/xiudi/xd60/rev2/info.json +++ b/keyboards/xiudi/xd60/rev2/info.json @@ -9,6 +9,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F5", "levels": 6, "on_state": 0 diff --git a/keyboards/xiudi/xd60/rev3/info.json b/keyboards/xiudi/xd60/rev3/info.json index c77b145607..6cc83bef59 100644 --- a/keyboards/xiudi/xd60/rev3/info.json +++ b/keyboards/xiudi/xd60/rev3/info.json @@ -9,6 +9,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F5", "levels": 6, "on_state": 0 diff --git a/keyboards/xiudi/xd68/info.json b/keyboards/xiudi/xd68/info.json index 27f40e6ee8..5332e1243f 100644 --- a/keyboards/xiudi/xd68/info.json +++ b/keyboards/xiudi/xd68/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F5", "levels": 6, "breathing": true, diff --git a/keyboards/xiudi/xd84pro/info.json b/keyboards/xiudi/xd84pro/info.json index 1df9eccb0f..697d267741 100644 --- a/keyboards/xiudi/xd84pro/info.json +++ b/keyboards/xiudi/xd84pro/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "F5", "levels": 10, "on_state": 0 diff --git a/keyboards/xiudi/xd87/info.json b/keyboards/xiudi/xd87/info.json index 4226947c25..74495b0f9f 100644 --- a/keyboards/xiudi/xd87/info.json +++ b/keyboards/xiudi/xd87/info.json @@ -14,6 +14,7 @@ }, "diode_direction": "COL2ROW", "backlight": { + "driver": "timer", "pin": "D0", "on_state": 0 }, diff --git a/platforms/avr/drivers/backlight_pwm.c b/platforms/avr/drivers/backlight_pwm.c index d234115641..74d25753a4 100644 --- a/platforms/avr/drivers/backlight_pwm.c +++ b/platforms/avr/drivers/backlight_pwm.c @@ -1,5 +1,5 @@ #include "backlight.h" -#include "backlight_driver_common.h" +#include "gpio.h" #include "progmem.h" #include #include @@ -9,14 +9,6 @@ # define BACKLIGHT_LIMIT_VAL 255 #endif -// This logic is a bit complex, we support 3 setups: -// -// 1. Hardware PWM when backlight is wired to a PWM pin. -// Depending on this pin, we use a different output compare unit. -// 2. Software PWM with hardware timers, but the used timer -// depends on the Audio setup (Audio wins over Backlight). -// 3. Full software PWM, driven by the matrix scan, if both timers are used by Audio. - #if (defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__)) && (BACKLIGHT_PIN == B5 || BACKLIGHT_PIN == B6 || BACKLIGHT_PIN == B7) # define ICRx ICR1 # define TCCRxA TCCR1A @@ -122,106 +114,34 @@ # define COMxx1 COM1B1 # define OCRxx OCR1B # endif -#elif (AUDIO_PIN != B5) && (AUDIO_PIN != B6) && (AUDIO_PIN != B7) && (AUDIO_PIN_ALT != B5) && (AUDIO_PIN_ALT != B6) && (AUDIO_PIN_ALT != B7) -// Timer 1 is not in use by Audio feature, Backlight can use it -# pragma message "Using hardware timer 1 with software PWM" -# define BACKLIGHT_PWM_TIMER -# define ICRx ICR1 -# define TCCRxA TCCR1A -# define TCCRxB TCCR1B -# define TIMERx_COMPA_vect TIMER1_COMPA_vect -# define TIMERx_OVF_vect TIMER1_OVF_vect -# if defined(__AVR_ATmega32A__) // This MCU has only one TIMSK register -# define TIMSKx TIMSK -# else -# define TIMSKx TIMSK1 -# endif -# define TOIEx TOIE1 - -# define OCIExA OCIE1A -# define OCRxx OCR1A -#elif (AUDIO_PIN != C4) && (AUDIO_PIN != C5) && (AUDIO_PIN != C6) -# pragma message "Using hardware timer 3 with software PWM" -// Timer 3 is not in use by Audio feature, Backlight can use it -# define BACKLIGHT_PWM_TIMER -# define ICRx ICR1 -# define TCCRxA TCCR3A -# define TCCRxB TCCR3B -# define TIMERx_COMPA_vect TIMER3_COMPA_vect -# define TIMERx_OVF_vect TIMER3_OVF_vect -# define TIMSKx TIMSK3 -# define TOIEx TOIE3 - -# define OCIExA OCIE3A -# define OCRxx OCR3A #endif -#ifndef BACKLIGHT_PWM_TIMER // pwm through software +#ifndef BACKLIGHT_RESOLUTION +# define BACKLIGHT_RESOLUTION 0xFFFFU +#endif + +#if (BACKLIGHT_RESOLUTION > 0xFFFF || BACKLIGHT_RESOLUTION < 0x00FF) +# error "Backlight resolution must be between 0x00FF and 0xFFFF" +#endif + +#define BREATHING_SCALE_FACTOR F_CPU / BACKLIGHT_RESOLUTION / 120 static inline void enable_pwm(void) { -# if BACKLIGHT_ON_STATE == 1 +#if BACKLIGHT_ON_STATE == 1 TCCRxA |= _BV(COMxx1); -# else +#else TCCRxA |= _BV(COMxx1) | _BV(COMxx0); -# endif +#endif } static inline void disable_pwm(void) { -# if BACKLIGHT_ON_STATE == 1 +#if BACKLIGHT_ON_STATE == 1 TCCRxA &= ~(_BV(COMxx1)); -# else +#else TCCRxA &= ~(_BV(COMxx1) | _BV(COMxx0)); -# endif -} - #endif - -#ifdef BACKLIGHT_PWM_TIMER - -// The idea of software PWM assisted by hardware timers is the following -// we use the hardware timer in fast PWM mode like for hardware PWM, but -// instead of letting the Output Match Comparator control the led pin -// (which is not possible since the backlight is not wired to PWM pins on the -// CPU), we do the LED on/off by oursleves. -// The timer is setup to count up to 0xFFFF, and we set the Output Compare -// register to the current 16bits backlight level (after CIE correction). -// This means the CPU will trigger a compare match interrupt when the counter -// reaches the backlight level, where we turn off the LEDs, -// but also an overflow interrupt when the counter rolls back to 0, -// in which we're going to turn on the LEDs. -// The LED will then be on for OCRxx/0xFFFF time, adjusted every 244Hz, -// or F_CPU/BACKLIGHT_CUSTOM_RESOLUTION if used. - -// Triggered when the counter reaches the OCRx value -ISR(TIMERx_COMPA_vect) { - backlight_pins_off(); } -// Triggered when the counter reaches the TOP value -// this one triggers at F_CPU/ICRx = 16MHz/65536 =~ 244 Hz -ISR(TIMERx_OVF_vect) { -# ifdef BACKLIGHT_BREATHING - if (is_breathing()) { - breathing_task(); - } -# endif - // for very small values of OCRxx (or backlight level) - // we can't guarantee this whole code won't execute - // at the same time as the compare match interrupt - // which means that we might turn on the leds while - // trying to turn them off, leading to flickering - // artifacts (especially while breathing, because breathing_task - // takes many computation cycles). - // so better not turn them on while the counter TOP is very low. - if (OCRxx > ICRx / 250 + 5) { - backlight_pins_on(); - } -} - -#endif - -#define TIMER_TOP 0xFFFFU - // See http://jared.geek.nz/2013/feb/linear-led-pwm static uint16_t cie_lightness(uint16_t v) { if (v <= (uint32_t)ICRx / 12) // If the value is less than or equal to ~8% of max @@ -254,26 +174,11 @@ void backlight_set(uint8_t level) { if (level > BACKLIGHT_LEVELS) level = BACKLIGHT_LEVELS; if (level == 0) { -#ifdef BACKLIGHT_PWM_TIMER - if (OCRxx) { - TIMSKx &= ~(_BV(OCIExA)); - TIMSKx &= ~(_BV(TOIEx)); - } -#else // Turn off PWM control on backlight pin disable_pwm(); -#endif - backlight_pins_off(); } else { -#ifdef BACKLIGHT_PWM_TIMER - if (!OCRxx) { - TIMSKx |= _BV(OCIExA); - TIMSKx |= _BV(TOIEx); - } -#else // Turn on PWM control of backlight pin enable_pwm(); -#endif } // Set the brightness set_pwm(cie_lightness(rescale_limit_val(ICRx * (uint32_t)level / BACKLIGHT_LEVELS))); @@ -282,7 +187,6 @@ void backlight_set(uint8_t level) { void backlight_task(void) {} #ifdef BACKLIGHT_BREATHING - # define BREATHING_NO_HALT 0 # define BREATHING_HALT_OFF 1 # define BREATHING_HALT_ON 2 @@ -293,39 +197,20 @@ static uint16_t breathing_counter = 0; static uint8_t breath_scale_counter = 1; /* Run the breathing loop at ~120Hz*/ -const uint8_t breathing_ISR_frequency = 120; -static uint16_t breathing_freq_scale_factor = 2; - -# ifdef BACKLIGHT_PWM_TIMER -static bool breathing = false; - -bool is_breathing(void) { - return breathing; -} - -# define breathing_interrupt_enable() \ - do { \ - breathing = true; \ - } while (0) -# define breathing_interrupt_disable() \ - do { \ - breathing = false; \ - } while (0) -# else +const uint8_t breathing_ISR_frequency = 120; bool is_breathing(void) { return !!(TIMSKx & _BV(TOIEx)); } -# define breathing_interrupt_enable() \ - do { \ - TIMSKx |= _BV(TOIEx); \ - } while (0) -# define breathing_interrupt_disable() \ - do { \ - TIMSKx &= ~_BV(TOIEx); \ - } while (0) -# endif +# define breathing_interrupt_enable() \ + do { \ + TIMSKx |= _BV(TOIEx); \ + } while (0) +# define breathing_interrupt_disable() \ + do { \ + TIMSKx &= ~_BV(TOIEx); \ + } while (0) # define breathing_min() \ do { \ @@ -374,20 +259,14 @@ static inline uint16_t scale_backlight(uint16_t v) { return v / BACKLIGHT_LEVELS * get_backlight_level(); } -# ifdef BACKLIGHT_PWM_TIMER -void breathing_task(void) -# else /* Assuming a 16MHz CPU clock and a timer that resets at 64k (ICR1), the following interrupt handler will run * about 244 times per second. * * The following ISR runs at F_CPU/ISRx. With a 16MHz clock and default pwm resolution, that means 244Hz */ -ISR(TIMERx_OVF_vect) -# endif -{ - +ISR(TIMERx_OVF_vect) { // Only run this ISR at ~120 Hz - if (breath_scale_counter++ == breathing_freq_scale_factor) { + if (breath_scale_counter++ == BREATHING_SCALE_FACTOR) { breath_scale_counter = 1; } else { return; @@ -412,19 +291,17 @@ ISR(TIMERx_OVF_vect) #endif // BACKLIGHT_BREATHING void backlight_init_ports(void) { - // Setup backlight pin as output and output to on state. - backlight_pins_init(); + setPinOutput(BACKLIGHT_PIN); +#if BACKLIGHT_ON_STATE == 1 + writePinLow(BACKLIGHT_PIN); +#else + writePinHigh(BACKLIGHT_PIN); +#endif // I could write a wall of text here to explain... but TL;DW // Go read the ATmega32u4 datasheet. // And this: http://blog.saikoled.com/post/43165849837/secret-konami-cheat-code-to-high-resolution-pwm-on -#ifdef BACKLIGHT_PWM_TIMER - // TimerX setup, Fast PWM mode count to TOP set in ICRx - TCCRxA = _BV(WGM11); // = 0b00000010; - // clock select clk/1 - TCCRxB = _BV(WGM13) | _BV(WGM12) | _BV(CS10); // = 0b00011001; -#else // hardware PWM // Pin PB7 = OCR1C (Timer 1, Channel C) // Compare Output Mode = Clear on compare match, Channel C = COM1C1=1 COM1C0=0 // (i.e. start high, go low when counter matches.) @@ -438,23 +315,10 @@ void backlight_init_ports(void) { */ TCCRxA = _BV(COMxx1) | _BV(WGM11); // = 0b00001010; TCCRxB = _BV(WGM13) | _BV(WGM12) | _BV(CS10); // = 0b00011001; -#endif - -#ifdef BACKLIGHT_CUSTOM_RESOLUTION -# if (BACKLIGHT_CUSTOM_RESOLUTION > 0xFFFF || BACKLIGHT_CUSTOM_RESOLUTION < 1) -# error "This out of range of the timer capabilities" -# elif (BACKLIGHT_CUSTOM_RESOLUTION < 0xFF) -# warning "Resolution lower than 0xFF isn't recommended" -# endif -# ifdef BACKLIGHT_BREATHING - breathing_freq_scale_factor = F_CPU / BACKLIGHT_CUSTOM_RESOLUTION / 120; -# endif - ICRx = BACKLIGHT_CUSTOM_RESOLUTION; -#else - ICRx = TIMER_TOP; -#endif + ICRx = BACKLIGHT_RESOLUTION; backlight_init(); + #ifdef BACKLIGHT_BREATHING if (is_backlight_breathing()) { breathing_enable(); diff --git a/platforms/avr/drivers/backlight_timer.c b/platforms/avr/drivers/backlight_timer.c new file mode 100644 index 0000000000..e1f4286557 --- /dev/null +++ b/platforms/avr/drivers/backlight_timer.c @@ -0,0 +1,267 @@ +#include "backlight.h" +#include "backlight_driver_common.h" +#include "progmem.h" +#include +#include + +// Maximum duty cycle limit +#ifndef BACKLIGHT_LIMIT_VAL +# define BACKLIGHT_LIMIT_VAL 255 +#endif + +#ifndef BACKLIGHT_PWM_TIMER +# define BACKLIGHT_PWM_TIMER 1 +#endif + +#if BACKLIGHT_PWM_TIMER == 1 +# define ICRx ICR1 +# define TCCRxA TCCR1A +# define TCCRxB TCCR1B +# define TIMERx_COMPA_vect TIMER1_COMPA_vect +# define TIMERx_OVF_vect TIMER1_OVF_vect +# if defined(__AVR_ATmega32A__) // This MCU has only one TIMSK register +# define TIMSKx TIMSK +# else +# define TIMSKx TIMSK1 +# endif +# define TOIEx TOIE1 + +# define OCIExA OCIE1A +# define OCRxx OCR1A +#elif BACKLIGHT_PWM_TIMER == 3 +# define ICRx ICR1 +# define TCCRxA TCCR3A +# define TCCRxB TCCR3B +# define TIMERx_COMPA_vect TIMER3_COMPA_vect +# define TIMERx_OVF_vect TIMER3_OVF_vect +# define TIMSKx TIMSK3 +# define TOIEx TOIE3 + +# define OCIExA OCIE3A +# define OCRxx OCR3A +#else +# error Invalid backlight PWM timer! +#endif + +#ifndef BACKLIGHT_RESOLUTION +# define BACKLIGHT_RESOLUTION 0xFFFFU +#endif + +#if (BACKLIGHT_RESOLUTION > 0xFFFF || BACKLIGHT_RESOLUTION < 0x00FF) +# error "Backlight resolution must be between 0x00FF and 0xFFFF" +#endif + +#define BREATHING_SCALE_FACTOR F_CPU / BACKLIGHT_RESOLUTION / 120 + +// The idea of software PWM assisted by hardware timers is the following +// we use the hardware timer in fast PWM mode like for hardware PWM, but +// instead of letting the Output Match Comparator control the led pin +// (which is not possible since the backlight is not wired to PWM pins on the +// CPU), we do the LED on/off by oursleves. +// The timer is setup to count up to 0xFFFF, and we set the Output Compare +// register to the current 16bits backlight level (after CIE correction). +// This means the CPU will trigger a compare match interrupt when the counter +// reaches the backlight level, where we turn off the LEDs, +// but also an overflow interrupt when the counter rolls back to 0, +// in which we're going to turn on the LEDs. +// The LED will then be on for OCRxx/0xFFFF time, adjusted every 244Hz, +// or F_CPU/BACKLIGHT_RESOLUTION if used. + +// Triggered when the counter reaches the OCRx value +ISR(TIMERx_COMPA_vect) { + backlight_pins_off(); +} + +// Triggered when the counter reaches the TOP value +// this one triggers at F_CPU/ICRx = 16MHz/65536 =~ 244 Hz +ISR(TIMERx_OVF_vect) { +#ifdef BACKLIGHT_BREATHING + if (is_breathing()) { + breathing_task(); + } +#endif + // for very small values of OCRxx (or backlight level) + // we can't guarantee this whole code won't execute + // at the same time as the compare match interrupt + // which means that we might turn on the leds while + // trying to turn them off, leading to flickering + // artifacts (especially while breathing, because breathing_task + // takes many computation cycles). + // so better not turn them on while the counter TOP is very low. + if (OCRxx > ICRx / 250 + 5) { + backlight_pins_on(); + } +} + +// See http://jared.geek.nz/2013/feb/linear-led-pwm +static uint16_t cie_lightness(uint16_t v) { + if (v <= (uint32_t)ICRx / 12) // If the value is less than or equal to ~8% of max + { + return v / 9; // Same as dividing by 900% + } else { + // In the next two lines values are bit-shifted. This is to avoid loosing decimals in integer math. + uint32_t y = (((uint32_t)v + (uint32_t)ICRx / 6) << 5) / ((uint32_t)ICRx / 6 + ICRx); // If above 8%, add ~16% of max, and normalize with (max + ~16% max) + uint32_t out = (y * y * y * ICRx) >> 15; // Cube it and undo the bit-shifting. (which is now three times as much due to the cubing) + + if (out > ICRx) // Avoid overflows + { + out = ICRx; + } + return (uint16_t)out; + } +} + +// rescale the supplied backlight value to be in terms of the value limit // range for val is [0..ICRx]. PWM pin is high while the timer count is below val. +static uint32_t rescale_limit_val(uint32_t val) { + return (val * (BACKLIGHT_LIMIT_VAL + 1)) / 256; +} + +// range for val is [0..ICRx]. PWM pin is high while the timer count is below val. +static inline void set_pwm(uint16_t val) { + OCRxx = val; +} + +void backlight_set(uint8_t level) { + if (level > BACKLIGHT_LEVELS) level = BACKLIGHT_LEVELS; + + if (level == 0) { + if (OCRxx) { + TIMSKx &= ~(_BV(OCIExA)); + TIMSKx &= ~(_BV(TOIEx)); + } + backlight_pins_off(); + } else { + if (!OCRxx) { + TIMSKx |= _BV(OCIExA); + TIMSKx |= _BV(TOIEx); + } + } + // Set the brightness + set_pwm(cie_lightness(rescale_limit_val(ICRx * (uint32_t)level / BACKLIGHT_LEVELS))); +} + +void backlight_task(void) {} + +#ifdef BACKLIGHT_BREATHING +# define BREATHING_NO_HALT 0 +# define BREATHING_HALT_OFF 1 +# define BREATHING_HALT_ON 2 +# define BREATHING_STEPS 128 + +static uint8_t breathing_halt = BREATHING_NO_HALT; +static uint16_t breathing_counter = 0; + +static uint8_t breath_scale_counter = 1; +/* Run the breathing loop at ~120Hz*/ +const uint8_t breathing_ISR_frequency = 120; + +static bool breathing = false; + +bool is_breathing(void) { + return breathing; +} + +# define breathing_interrupt_enable() \ + do { \ + breathing = true; \ + } while (0) +# define breathing_interrupt_disable() \ + do { \ + breathing = false; \ + } while (0) + +# define breathing_min() \ + do { \ + breathing_counter = 0; \ + } while (0) +# define breathing_max() \ + do { \ + breathing_counter = get_breathing_period() * breathing_ISR_frequency / 2; \ + } while (0) + +void breathing_enable(void) { + breathing_counter = 0; + breathing_halt = BREATHING_NO_HALT; + breathing_interrupt_enable(); +} + +void breathing_pulse(void) { + if (get_backlight_level() == 0) + breathing_min(); + else + breathing_max(); + breathing_halt = BREATHING_HALT_ON; + breathing_interrupt_enable(); +} + +void breathing_disable(void) { + breathing_interrupt_disable(); + // Restore backlight level + backlight_set(get_backlight_level()); +} + +void breathing_self_disable(void) { + if (get_backlight_level() == 0) + breathing_halt = BREATHING_HALT_OFF; + else + breathing_halt = BREATHING_HALT_ON; +} + +/* To generate breathing curve in python: + * from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)] + */ +static const uint8_t breathing_table[BREATHING_STEPS] PROGMEM = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 17, 20, 24, 28, 32, 36, 41, 46, 51, 57, 63, 70, 76, 83, 91, 98, 106, 113, 121, 129, 138, 146, 154, 162, 170, 178, 185, 193, 200, 207, 213, 220, 225, 231, 235, 240, 244, 247, 250, 252, 253, 254, 255, 254, 253, 252, 250, 247, 244, 240, 235, 231, 225, 220, 213, 207, 200, 193, 185, 178, 170, 162, 154, 146, 138, 129, 121, 113, 106, 98, 91, 83, 76, 70, 63, 57, 51, 46, 41, 36, 32, 28, 24, 20, 17, 15, 12, 10, 8, 6, 5, 4, 3, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; + +// Use this before the cie_lightness function. +static inline uint16_t scale_backlight(uint16_t v) { + return v / BACKLIGHT_LEVELS * get_backlight_level(); +} + +void breathing_task(void) { + // Only run this ISR at ~120 Hz + if (breath_scale_counter++ == BREATHING_SCALE_FACTOR) { + breath_scale_counter = 1; + } else { + return; + } + uint16_t interval = (uint16_t)get_breathing_period() * breathing_ISR_frequency / BREATHING_STEPS; + // resetting after one period to prevent ugly reset at overflow. + breathing_counter = (breathing_counter + 1) % (get_breathing_period() * breathing_ISR_frequency); + uint8_t index = breathing_counter / interval; + // limit index to max step value + if (index >= BREATHING_STEPS) { + index = BREATHING_STEPS - 1; + } + + if (((breathing_halt == BREATHING_HALT_ON) && (index == BREATHING_STEPS / 2)) || ((breathing_halt == BREATHING_HALT_OFF) && (index == BREATHING_STEPS - 1))) { + breathing_interrupt_disable(); + } + + // Set PWM to a brightnessvalue scaled to the configured resolution + set_pwm(cie_lightness(rescale_limit_val(scale_backlight((uint32_t)pgm_read_byte(&breathing_table[index]) * ICRx / 255)))); +} + +#endif // BACKLIGHT_BREATHING + +void backlight_init_ports(void) { + // Setup backlight pin as output and output to on state. + backlight_pins_init(); + + // I could write a wall of text here to explain... but TL;DW + // Go read the ATmega32u4 datasheet. + // And this: http://blog.saikoled.com/post/43165849837/secret-konami-cheat-code-to-high-resolution-pwm-on + + // TimerX setup, Fast PWM mode count to TOP set in ICRx + TCCRxA = _BV(WGM11); // = 0b00000010; + // clock select clk/1 + TCCRxB = _BV(WGM13) | _BV(WGM12) | _BV(CS10); // = 0b00011001; + ICRx = BACKLIGHT_RESOLUTION; + + backlight_init(); + +#ifdef BACKLIGHT_BREATHING + if (is_backlight_breathing()) { + breathing_enable(); + } +#endif +}