Relocate backlight drivers (#21444)
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								platforms/avr/drivers/backlight_pwm.c
									
										
									
									
									
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								platforms/avr/drivers/backlight_pwm.c
									
										
									
									
									
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							|  | @ -0,0 +1,463 @@ | |||
| #include "backlight.h" | ||||
| #include "backlight_driver_common.h" | ||||
| #include "progmem.h" | ||||
| #include <avr/io.h> | ||||
| #include <avr/interrupt.h> | ||||
| 
 | ||||
| // Maximum duty cycle limit
 | ||||
| #ifndef BACKLIGHT_LIMIT_VAL | ||||
| #    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 | ||||
| #    define TCCRxB TCCR1B | ||||
| #    define TIMERx_OVF_vect TIMER1_OVF_vect | ||||
| #    define TIMSKx TIMSK1 | ||||
| #    define TOIEx TOIE1 | ||||
| 
 | ||||
| #    if BACKLIGHT_PIN == B5 | ||||
| #        define COMxx0 COM1A0 | ||||
| #        define COMxx1 COM1A1 | ||||
| #        define OCRxx OCR1A | ||||
| #    elif BACKLIGHT_PIN == B6 | ||||
| #        define COMxx0 COM1B0 | ||||
| #        define COMxx1 COM1B1 | ||||
| #        define OCRxx OCR1B | ||||
| #    elif BACKLIGHT_PIN == B7 | ||||
| #        define COMxx0 COM1C0 | ||||
| #        define COMxx1 COM1C1 | ||||
| #        define OCRxx OCR1C | ||||
| #    endif | ||||
| #elif (defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__)) && (BACKLIGHT_PIN == C4 || BACKLIGHT_PIN == C5 || BACKLIGHT_PIN == C6) | ||||
| #    define ICRx ICR3 | ||||
| #    define TCCRxA TCCR3A | ||||
| #    define TCCRxB TCCR3B | ||||
| #    define TIMERx_OVF_vect TIMER3_OVF_vect | ||||
| #    define TIMSKx TIMSK3 | ||||
| #    define TOIEx TOIE3 | ||||
| 
 | ||||
| #    if BACKLIGHT_PIN == C4 | ||||
| #        if (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__)) | ||||
| #            error This MCU has no C4 pin! | ||||
| #        else | ||||
| #            define COMxx0 COM3C0 | ||||
| #            define COMxx1 COM3C1 | ||||
| #            define OCRxx OCR3C | ||||
| #        endif | ||||
| #    elif BACKLIGHT_PIN == C5 | ||||
| #        if (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__)) | ||||
| #            error This MCU has no C5 pin! | ||||
| #        else | ||||
| #            define COMxx0 COM3B0 | ||||
| #            define COMxx1 COM3B1 | ||||
| #            define OCRxx OCR3B | ||||
| #        endif | ||||
| #    elif BACKLIGHT_PIN == C6 | ||||
| #        define COMxx0 COM3A0 | ||||
| #        define COMxx1 COM3A1 | ||||
| #        define OCRxx OCR3A | ||||
| #    endif | ||||
| #elif (defined(__AVR_AT90USB162__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__)) && (BACKLIGHT_PIN == B7 || BACKLIGHT_PIN == C5 || BACKLIGHT_PIN == C6) | ||||
| #    define ICRx ICR1 | ||||
| #    define TCCRxA TCCR1A | ||||
| #    define TCCRxB TCCR1B | ||||
| #    define TIMERx_OVF_vect TIMER1_OVF_vect | ||||
| #    define TIMSKx TIMSK1 | ||||
| #    define TOIEx TOIE1 | ||||
| 
 | ||||
| #    if BACKLIGHT_PIN == B7 | ||||
| #        define COMxx0 COM1C0 | ||||
| #        define COMxx1 COM1C1 | ||||
| #        define OCRxx OCR1C | ||||
| #    elif BACKLIGHT_PIN == C5 | ||||
| #        define COMxx0 COM1B0 | ||||
| #        define COMxx1 COM1B1 | ||||
| #        define OCRxx OCR1B | ||||
| #    elif BACKLIGHT_PIN == C6 | ||||
| #        define COMxx0 COM1A0 | ||||
| #        define COMxx1 COM1A1 | ||||
| #        define OCRxx OCR1A | ||||
| #    endif | ||||
| #elif defined(__AVR_ATmega32A__) && (BACKLIGHT_PIN == D4 || BACKLIGHT_PIN == D5) | ||||
| #    define ICRx ICR1 | ||||
| #    define TCCRxA TCCR1A | ||||
| #    define TCCRxB TCCR1B | ||||
| #    define TIMERx_OVF_vect TIMER1_OVF_vect | ||||
| #    define TIMSKx TIMSK | ||||
| #    define TOIEx TOIE1 | ||||
| 
 | ||||
| #    if BACKLIGHT_PIN == D4 | ||||
| #        define COMxx0 COM1B0 | ||||
| #        define COMxx1 COM1B1 | ||||
| #        define OCRxx OCR1B | ||||
| #    elif BACKLIGHT_PIN == D5 | ||||
| #        define COMxx0 COM1A0 | ||||
| #        define COMxx1 COM1A1 | ||||
| #        define OCRxx OCR1A | ||||
| #    endif | ||||
| #elif (defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328__)) && (BACKLIGHT_PIN == B1 || BACKLIGHT_PIN == B2) | ||||
| #    define ICRx ICR1 | ||||
| #    define TCCRxA TCCR1A | ||||
| #    define TCCRxB TCCR1B | ||||
| #    define TIMERx_OVF_vect TIMER1_OVF_vect | ||||
| #    define TIMSKx TIMSK1 | ||||
| #    define TOIEx TOIE1 | ||||
| 
 | ||||
| #    if BACKLIGHT_PIN == B1 | ||||
| #        define COMxx0 COM1A0 | ||||
| #        define COMxx1 COM1A1 | ||||
| #        define OCRxx OCR1A | ||||
| #    elif BACKLIGHT_PIN == B2 | ||||
| #        define COMxx0 COM1B0 | ||||
| #        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
 | ||||
| 
 | ||||
| static inline void enable_pwm(void) { | ||||
| #    if BACKLIGHT_ON_STATE == 1 | ||||
|     TCCRxA |= _BV(COMxx1); | ||||
| #    else | ||||
|     TCCRxA |= _BV(COMxx1) | _BV(COMxx0); | ||||
| #    endif | ||||
| } | ||||
| 
 | ||||
| static inline void disable_pwm(void) { | ||||
| #    if BACKLIGHT_ON_STATE == 1 | ||||
|     TCCRxA &= ~(_BV(COMxx1)); | ||||
| #    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
 | ||||
|     { | ||||
|         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) { | ||||
| #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))); | ||||
| } | ||||
| 
 | ||||
| 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 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 | ||||
| 
 | ||||
| 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_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(); | ||||
| } | ||||
| 
 | ||||
| #    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 | ||||
| { | ||||
| 
 | ||||
|     // Only run this ISR at ~120 Hz
 | ||||
|     if (breath_scale_counter++ == breathing_freq_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
 | ||||
| 
 | ||||
| #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.)
 | ||||
|     // WGM Mode 14 (Fast PWM) = WGM13=1 WGM12=1 WGM11=1 WGM10=0
 | ||||
|     // Clock Select = clk/1 (no prescaling) = CS12=0 CS11=0 CS10=1
 | ||||
| 
 | ||||
|     /*
 | ||||
|     14.8.3: | ||||
|     "In fast PWM mode, the compare units allow generation of PWM waveforms on the OCnx pins. Setting the COMnx1:0 bits to two will produce a non-inverted PWM [..]." | ||||
|     "In fast PWM mode the counter is incremented until the counter value matches either one of the fixed values 0x00FF, 0x01FF, or 0x03FF (WGMn3:0 = 5, 6, or 7), the value in ICRn (WGMn3:0 = 14), or the value in OCRnA (WGMn3:0 = 15)." | ||||
|     */ | ||||
|     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 | ||||
| 
 | ||||
|     backlight_init(); | ||||
| #ifdef BACKLIGHT_BREATHING | ||||
|     if (is_backlight_breathing()) { | ||||
|         breathing_enable(); | ||||
|     } | ||||
| #endif | ||||
| } | ||||
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