426 lines
15 KiB
C
426 lines
15 KiB
C
#include "quantum.h"
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#include "backlight.h"
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#include "backlight_driver_common.h"
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#include "debug.h"
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// This logic is a bit complex, we support 3 setups:
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//
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// 1. Hardware PWM when backlight is wired to a PWM pin.
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// Depending on this pin, we use a different output compare unit.
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// 2. Software PWM with hardware timers, but the used timer
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// depends on the Audio setup (Audio wins over Backlight).
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// 3. Full software PWM, driven by the matrix scan, if both timers are used by Audio.
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#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)
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# define HARDWARE_PWM
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# define ICRx ICR1
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# define TCCRxA TCCR1A
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# define TCCRxB TCCR1B
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# define TIMERx_OVF_vect TIMER1_OVF_vect
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# define TIMSKx TIMSK1
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# define TOIEx TOIE1
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# if BACKLIGHT_PIN == B5
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# define COMxx0 COM1A0
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# define COMxx1 COM1A1
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# define OCRxx OCR1A
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# elif BACKLIGHT_PIN == B6
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# define COMxx0 COM1B0
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# define COMxx1 COM1B1
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# define OCRxx OCR1B
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# elif BACKLIGHT_PIN == B7
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# define COMxx0 COM1C0
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# define COMxx1 COM1C1
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# define OCRxx OCR1C
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# endif
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#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)
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# define HARDWARE_PWM
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# define ICRx ICR3
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# define TCCRxA TCCR3A
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# define TCCRxB TCCR3B
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# define TIMERx_OVF_vect TIMER3_OVF_vect
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# define TIMSKx TIMSK3
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# define TOIEx TOIE3
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# if BACKLIGHT_PIN == C4
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# if (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
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# error This MCU has no C4 pin!
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# else
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# define COMxx0 COM3C0
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# define COMxx1 COM3C1
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# define OCRxx OCR3C
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# endif
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# elif BACKLIGHT_PIN == C5
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# if (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
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# error This MCU has no C5 pin!
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# else
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# define COMxx0 COM3B0
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# define COMxx1 COM3B1
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# define OCRxx OCR3B
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# endif
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# elif BACKLIGHT_PIN == C6
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# define COMxx0 COM3A0
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# define COMxx1 COM3A1
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# define OCRxx OCR3A
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# endif
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#elif (defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__)) && (BACKLIGHT_PIN == B7 || BACKLIGHT_PIN == C5 || BACKLIGHT_PIN == C6)
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# define HARDWARE_PWM
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# define ICRx ICR1
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# define TCCRxA TCCR1A
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# define TCCRxB TCCR1B
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# define TIMERx_OVF_vect TIMER1_OVF_vect
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# define TIMSKx TIMSK1
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# define TOIEx TOIE1
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# if BACKLIGHT_PIN == B7
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# define COMxx0 COM1C0
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# define COMxx1 COM1C1
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# define OCRxx OCR1C
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# elif BACKLIGHT_PIN == C5
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# define COMxx0 COM1B0
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# define COMxx1 COM1B1
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# define OCRxx OCR1B
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# elif BACKLIGHT_PIN == C6
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# define COMxx0 COM1A0
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# define COMxx1 COM1A1
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# define OCRxx OCR1A
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# endif
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#elif defined(__AVR_ATmega32A__) && (BACKLIGHT_PIN == D4 || BACKLIGHT_PIN == D5)
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# define HARDWARE_PWM
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# define ICRx ICR1
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# define TCCRxA TCCR1A
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# define TCCRxB TCCR1B
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# define TIMERx_OVF_vect TIMER1_OVF_vect
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# define TIMSKx TIMSK
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# define TOIEx TOIE1
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# if BACKLIGHT_PIN == D4
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# define COMxx0 COM1B0
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# define COMxx1 COM1B1
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# define OCRxx OCR1B
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# elif BACKLIGHT_PIN == D5
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# define COMxx0 COM1A0
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# define COMxx1 COM1A1
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# define OCRxx OCR1A
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# endif
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#elif defined(__AVR_ATmega328P__) && (BACKLIGHT_PIN == B1 || BACKLIGHT_PIN == B2)
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# define HARDWARE_PWM
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# define ICRx ICR1
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# define TCCRxA TCCR1A
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# define TCCRxB TCCR1B
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# define TIMERx_OVF_vect TIMER1_OVF_vect
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# define TIMSKx TIMSK1
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# define TOIEx TOIE1
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# if BACKLIGHT_PIN == B1
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# define COMxx0 COM1A0
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# define COMxx1 COM1A1
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# define OCRxx OCR1A
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# elif BACKLIGHT_PIN == B2
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# define COMxx0 COM1B0
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# define COMxx1 COM1B1
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# define OCRxx OCR1B
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# endif
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#elif !defined(B5_AUDIO) && !defined(B6_AUDIO) && !defined(B7_AUDIO)
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// Timer 1 is not in use by Audio feature, Backlight can use it
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# pragma message "Using hardware timer 1 with software PWM"
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# define HARDWARE_PWM
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# define BACKLIGHT_PWM_TIMER
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# define ICRx ICR1
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# define TCCRxA TCCR1A
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# define TCCRxB TCCR1B
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# define TIMERx_COMPA_vect TIMER1_COMPA_vect
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# define TIMERx_OVF_vect TIMER1_OVF_vect
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# if defined(__AVR_ATmega32A__) // This MCU has only one TIMSK register
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# define TIMSKx TIMSK
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# else
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# define TIMSKx TIMSK1
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# endif
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# define TOIEx TOIE1
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# define OCIExA OCIE1A
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# define OCRxx OCR1A
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#elif !defined(C6_AUDIO) && !defined(C5_AUDIO) && !defined(C4_AUDIO)
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# pragma message "Using hardware timer 3 with software PWM"
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// Timer 3 is not in use by Audio feature, Backlight can use it
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# define HARDWARE_PWM
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# define BACKLIGHT_PWM_TIMER
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# define ICRx ICR1
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# define TCCRxA TCCR3A
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# define TCCRxB TCCR3B
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# define TIMERx_COMPA_vect TIMER3_COMPA_vect
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# define TIMERx_OVF_vect TIMER3_OVF_vect
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# define TIMSKx TIMSK3
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# define TOIEx TOIE3
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# define OCIExA OCIE3A
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# define OCRxx OCR3A
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#elif defined(BACKLIGHT_CUSTOM_DRIVER)
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error("Please set 'BACKLIGHT_DRIVER = custom' within rules.mk")
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#else
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error("Please set 'BACKLIGHT_DRIVER = software' within rules.mk")
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#endif
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#ifndef BACKLIGHT_PWM_TIMER // pwm through software
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static inline void enable_pwm(void) {
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# if BACKLIGHT_ON_STATE == 1
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TCCRxA |= _BV(COMxx1);
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# else
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TCCRxA |= _BV(COMxx1) | _BV(COMxx0);
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# endif
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}
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static inline void disable_pwm(void) {
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# if BACKLIGHT_ON_STATE == 1
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TCCRxA &= ~(_BV(COMxx1));
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# else
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TCCRxA &= ~(_BV(COMxx1) | _BV(COMxx0));
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# endif
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}
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#endif
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#ifdef BACKLIGHT_PWM_TIMER
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// The idea of software PWM assisted by hardware timers is the following
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// we use the hardware timer in fast PWM mode like for hardware PWM, but
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// instead of letting the Output Match Comparator control the led pin
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// (which is not possible since the backlight is not wired to PWM pins on the
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// CPU), we do the LED on/off by oursleves.
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// The timer is setup to count up to 0xFFFF, and we set the Output Compare
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// register to the current 16bits backlight level (after CIE correction).
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// This means the CPU will trigger a compare match interrupt when the counter
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// reaches the backlight level, where we turn off the LEDs,
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// but also an overflow interrupt when the counter rolls back to 0,
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// in which we're going to turn on the LEDs.
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// The LED will then be on for OCRxx/0xFFFF time, adjusted every 244Hz.
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// Triggered when the counter reaches the OCRx value
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ISR(TIMERx_COMPA_vect) { backlight_pins_off(); }
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// Triggered when the counter reaches the TOP value
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// this one triggers at F_CPU/65536 =~ 244 Hz
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ISR(TIMERx_OVF_vect) {
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# ifdef BACKLIGHT_BREATHING
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if (is_breathing()) {
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breathing_task();
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}
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# endif
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// for very small values of OCRxx (or backlight level)
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// we can't guarantee this whole code won't execute
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// at the same time as the compare match interrupt
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// which means that we might turn on the leds while
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// trying to turn them off, leading to flickering
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// artifacts (especially while breathing, because breathing_task
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// takes many computation cycles).
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// so better not turn them on while the counter TOP is very low.
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if (OCRxx > 256) {
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backlight_pins_on();
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}
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}
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#endif
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#define TIMER_TOP 0xFFFFU
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// See http://jared.geek.nz/2013/feb/linear-led-pwm
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static uint16_t cie_lightness(uint16_t v) {
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if (v <= 5243) // if below 8% of max
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return v / 9; // same as dividing by 900%
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else {
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uint32_t y = (((uint32_t)v + 10486) << 8) / (10486 + 0xFFFFUL); // add 16% of max and compare
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// to get a useful result with integer division, we shift left in the expression above
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// and revert what we've done again after squaring.
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y = y * y * y >> 8;
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if (y > 0xFFFFUL) // prevent overflow
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return 0xFFFFU;
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else
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return (uint16_t)y;
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}
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}
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// range for val is [0..TIMER_TOP]. PWM pin is high while the timer count is below val.
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static inline void set_pwm(uint16_t val) { OCRxx = val; }
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void backlight_set(uint8_t level) {
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if (level > BACKLIGHT_LEVELS) level = BACKLIGHT_LEVELS;
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if (level == 0) {
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#ifdef BACKLIGHT_PWM_TIMER
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if (OCRxx) {
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TIMSKx &= ~(_BV(OCIExA));
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TIMSKx &= ~(_BV(TOIEx));
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}
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#else
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// Turn off PWM control on backlight pin
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disable_pwm();
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#endif
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backlight_pins_off();
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} else {
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#ifdef BACKLIGHT_PWM_TIMER
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if (!OCRxx) {
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TIMSKx |= _BV(OCIExA);
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TIMSKx |= _BV(TOIEx);
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}
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#else
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// Turn on PWM control of backlight pin
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enable_pwm();
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#endif
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}
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// Set the brightness
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set_pwm(cie_lightness(TIMER_TOP * (uint32_t)level / BACKLIGHT_LEVELS));
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}
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void backlight_task(void) {}
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#ifdef BACKLIGHT_BREATHING
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# define BREATHING_NO_HALT 0
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# define BREATHING_HALT_OFF 1
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# define BREATHING_HALT_ON 2
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# define BREATHING_STEPS 128
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static uint8_t breathing_halt = BREATHING_NO_HALT;
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static uint16_t breathing_counter = 0;
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# ifdef BACKLIGHT_PWM_TIMER
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static bool breathing = false;
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bool is_breathing(void) { return breathing; }
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# define breathing_interrupt_enable() \
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do { \
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breathing = true; \
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} while (0)
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# define breathing_interrupt_disable() \
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do { \
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breathing = false; \
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} while (0)
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# else
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bool is_breathing(void) { return !!(TIMSKx & _BV(TOIEx)); }
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# define breathing_interrupt_enable() \
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do { \
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TIMSKx |= _BV(TOIEx); \
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} while (0)
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# define breathing_interrupt_disable() \
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do { \
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TIMSKx &= ~_BV(TOIEx); \
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} while (0)
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# endif
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# define breathing_min() \
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do { \
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breathing_counter = 0; \
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} while (0)
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# define breathing_max() \
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do { \
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breathing_counter = get_breathing_period() * 244 / 2; \
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} while (0)
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void breathing_enable(void) {
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breathing_counter = 0;
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breathing_halt = BREATHING_NO_HALT;
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breathing_interrupt_enable();
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}
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void breathing_pulse(void) {
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if (get_backlight_level() == 0)
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breathing_min();
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else
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breathing_max();
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breathing_halt = BREATHING_HALT_ON;
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breathing_interrupt_enable();
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}
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void breathing_disable(void) {
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breathing_interrupt_disable();
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// Restore backlight level
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backlight_set(get_backlight_level());
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}
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void breathing_self_disable(void) {
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if (get_backlight_level() == 0)
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breathing_halt = BREATHING_HALT_OFF;
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else
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breathing_halt = BREATHING_HALT_ON;
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}
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/* To generate breathing curve in python:
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* from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)]
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*/
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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};
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// Use this before the cie_lightness function.
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static inline uint16_t scale_backlight(uint16_t v) { return v / BACKLIGHT_LEVELS * get_backlight_level(); }
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# ifdef BACKLIGHT_PWM_TIMER
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void breathing_task(void)
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# else
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/* Assuming a 16MHz CPU clock and a timer that resets at 64k (ICR1), the following interrupt handler will run
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* about 244 times per second.
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*/
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ISR(TIMERx_OVF_vect)
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# endif
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{
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uint8_t breathing_period = get_breathing_period();
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uint16_t interval = (uint16_t)breathing_period * 244 / BREATHING_STEPS;
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// resetting after one period to prevent ugly reset at overflow.
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breathing_counter = (breathing_counter + 1) % (breathing_period * 244);
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uint8_t index = breathing_counter / interval % BREATHING_STEPS;
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if (((breathing_halt == BREATHING_HALT_ON) && (index == BREATHING_STEPS / 2)) || ((breathing_halt == BREATHING_HALT_OFF) && (index == BREATHING_STEPS - 1))) {
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breathing_interrupt_disable();
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}
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set_pwm(cie_lightness(scale_backlight((uint16_t)pgm_read_byte(&breathing_table[index]) * 0x0101U)));
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}
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#endif // BACKLIGHT_BREATHING
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void backlight_init_ports(void) {
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// Setup backlight pin as output and output to on state.
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backlight_pins_init();
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// I could write a wall of text here to explain... but TL;DW
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// Go read the ATmega32u4 datasheet.
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// And this: http://blog.saikoled.com/post/43165849837/secret-konami-cheat-code-to-high-resolution-pwm-on
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#ifdef BACKLIGHT_PWM_TIMER
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// TimerX setup, Fast PWM mode count to TOP set in ICRx
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TCCRxA = _BV(WGM11); // = 0b00000010;
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// clock select clk/1
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TCCRxB = _BV(WGM13) | _BV(WGM12) | _BV(CS10); // = 0b00011001;
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#else // hardware PWM
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// Pin PB7 = OCR1C (Timer 1, Channel C)
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// Compare Output Mode = Clear on compare match, Channel C = COM1C1=1 COM1C0=0
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// (i.e. start high, go low when counter matches.)
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// WGM Mode 14 (Fast PWM) = WGM13=1 WGM12=1 WGM11=1 WGM10=0
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// Clock Select = clk/1 (no prescaling) = CS12=0 CS11=0 CS10=1
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/*
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14.8.3:
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"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 [..]."
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"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)."
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*/
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# if BACKLIGHT_ON_STATE == 1
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TCCRxA = _BV(COMxx1) | _BV(WGM11);
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# else
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TCCRxA = _BV(COMxx1) | _BV(COMxx0) | _BV(WGM11);
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# endif
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TCCRxB = _BV(WGM13) | _BV(WGM12) | _BV(CS10);
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#endif
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// Use full 16-bit resolution. Counter counts to ICR1 before reset to 0.
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ICRx = TIMER_TOP;
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backlight_init();
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#ifdef BACKLIGHT_BREATHING
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if (is_backlight_breathing()) {
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breathing_enable();
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}
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#endif
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}
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