#include "quantum.h" #include "backlight.h" #include "backlight_driver_common.h" #include "debug.h" // 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 HARDWARE_PWM # 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 HARDWARE_PWM # 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_ATmega16U2__) || defined(__AVR_ATmega32U2__)) && (BACKLIGHT_PIN == B7 || BACKLIGHT_PIN == C5 || BACKLIGHT_PIN == C6) # define HARDWARE_PWM # 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 HARDWARE_PWM # 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__) && (BACKLIGHT_PIN == B1 || BACKLIGHT_PIN == B2) # define HARDWARE_PWM # 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 !defined(B5_AUDIO) && !defined(B6_AUDIO) && !defined(B7_AUDIO) // Timer 1 is not in use by Audio feature, Backlight can use it # pragma message "Using hardware timer 1 with software PWM" # define HARDWARE_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 !defined(C6_AUDIO) && !defined(C5_AUDIO) && !defined(C4_AUDIO) # pragma message "Using hardware timer 3 with software PWM" // Timer 3 is not in use by Audio feature, Backlight can use it # define HARDWARE_PWM # 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 #elif defined(BACKLIGHT_CUSTOM_DRIVER) error("Please set 'BACKLIGHT_DRIVER = custom' within rules.mk") #else error("Please set 'BACKLIGHT_DRIVER = software' within rules.mk") #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. // 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/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 > 256) { 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 <= 5243) // if below 8% of max return v / 9; // same as dividing by 900% else { uint32_t y = (((uint32_t)v + 10486) << 8) / (10486 + 0xFFFFUL); // add 16% of max and compare // to get a useful result with integer division, we shift left in the expression above // and revert what we've done again after squaring. y = y * y * y >> 8; if (y > 0xFFFFUL) // prevent overflow return 0xFFFFU; else return (uint16_t)y; } } // range for val is [0..TIMER_TOP]. 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(TIMER_TOP * (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; # 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() * 244 / 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. */ ISR(TIMERx_OVF_vect) # endif { uint8_t breathing_period = get_breathing_period(); uint16_t interval = (uint16_t)breathing_period * 244 / BREATHING_STEPS; // resetting after one period to prevent ugly reset at overflow. breathing_counter = (breathing_counter + 1) % (breathing_period * 244); uint8_t index = breathing_counter / interval % BREATHING_STEPS; if (((breathing_halt == BREATHING_HALT_ON) && (index == BREATHING_STEPS / 2)) || ((breathing_halt == BREATHING_HALT_OFF) && (index == BREATHING_STEPS - 1))) { breathing_interrupt_disable(); } set_pwm(cie_lightness(scale_backlight((uint16_t)pgm_read_byte(&breathing_table[index]) * 0x0101U))); } #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)." */ # if BACKLIGHT_ON_STATE == 1 TCCRxA = _BV(COMxx1) | _BV(WGM11); # else TCCRxA = _BV(COMxx1) | _BV(COMxx0) | _BV(WGM11); # endif TCCRxB = _BV(WGM13) | _BV(WGM12) | _BV(CS10); #endif // Use full 16-bit resolution. Counter counts to ICR1 before reset to 0. ICRx = TIMER_TOP; backlight_init(); #ifdef BACKLIGHT_BREATHING if (is_backlight_breathing()) { breathing_enable(); } #endif }