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- #include "quantum.h"
- #include "backlight.h"
- #include "debug.h"
- #if defined(BACKLIGHT_ENABLE) && (defined(BACKLIGHT_PIN) || defined(BACKLIGHT_PINS))
- // 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 COMxx1 COM1A1
- # define OCRxx OCR1A
- # elif BACKLIGHT_PIN == B6
- # define COMxx1 COM1B1
- # define OCRxx OCR1B
- # elif BACKLIGHT_PIN == B7
- # 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 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 COMxx1 COM3B1
- # define OCRxx OCR3B
- # endif
- # elif BACKLIGHT_PIN == C6
- # 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 COMxx1 COM1C1
- # define OCRxx OCR1C
- # elif BACKLIGHT_PIN == C5
- # define COMxx1 COM1B1
- # define OCRxx OCR1B
- # elif BACKLIGHT_PIN == C6
- # 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 COMxx1 COM1B1
- # define OCRxx OCR1B
- # elif BACKLIGHT_PIN == D5
- # 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 COMxx1 COM1A1
- # define OCRxx OCR1A
- # elif BACKLIGHT_PIN == B2
- # define COMxx1 COM1B1
- # define OCRxx OCR1B
- # endif
- # else
- # if !defined(BACKLIGHT_CUSTOM_DRIVER)
- # if !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
- # else
- # pragma message "Audio in use - using pure software PWM"
- # define NO_HARDWARE_PWM
- # endif
- # else
- # pragma message "Custom driver defined - using pure software PWM"
- # define NO_HARDWARE_PWM
- # endif
- # endif
- # ifndef BACKLIGHT_ON_STATE
- # define BACKLIGHT_ON_STATE 0
- # endif
- void backlight_on(pin_t backlight_pin) {
- # if BACKLIGHT_ON_STATE == 0
- writePinLow(backlight_pin);
- # else
- writePinHigh(backlight_pin);
- # endif
- }
- void backlight_off(pin_t backlight_pin) {
- # if BACKLIGHT_ON_STATE == 0
- writePinHigh(backlight_pin);
- # else
- writePinLow(backlight_pin);
- # endif
- }
- # if defined(NO_HARDWARE_PWM) || defined(BACKLIGHT_PWM_TIMER) // pwm through software
- // we support multiple backlight pins
- # ifndef BACKLIGHT_LED_COUNT
- # define BACKLIGHT_LED_COUNT 1
- # endif
- # if BACKLIGHT_LED_COUNT == 1
- # define BACKLIGHT_PIN_INIT \
- { BACKLIGHT_PIN }
- # else
- # define BACKLIGHT_PIN_INIT BACKLIGHT_PINS
- # endif
- # define FOR_EACH_LED(x) \
- for (uint8_t i = 0; i < BACKLIGHT_LED_COUNT; i++) { \
- pin_t backlight_pin = backlight_pins[i]; \
- { x } \
- }
- static const pin_t backlight_pins[BACKLIGHT_LED_COUNT] = BACKLIGHT_PIN_INIT;
- # else // full hardware PWM
- // we support only one backlight pin
- static const pin_t backlight_pin = BACKLIGHT_PIN;
- # define FOR_EACH_LED(x) x
- # endif
- # ifdef NO_HARDWARE_PWM
- __attribute__((weak)) void backlight_init_ports(void) {
- // Setup backlight pin as output and output to on state.
- FOR_EACH_LED(setPinOutput(backlight_pin); backlight_on(backlight_pin);)
- # ifdef BACKLIGHT_BREATHING
- if (is_backlight_breathing()) {
- breathing_enable();
- }
- # endif
- }
- __attribute__((weak)) void backlight_set(uint8_t level) {}
- uint8_t backlight_tick = 0;
- # ifndef BACKLIGHT_CUSTOM_DRIVER
- void backlight_task(void) {
- if ((0xFFFF >> ((BACKLIGHT_LEVELS - get_backlight_level()) * ((BACKLIGHT_LEVELS + 1) / 2))) & (1 << backlight_tick)) {
- FOR_EACH_LED(backlight_on(backlight_pin);)
- } else {
- FOR_EACH_LED(backlight_off(backlight_pin);)
- }
- backlight_tick = (backlight_tick + 1) % 16;
- }
- # endif
- # ifdef BACKLIGHT_BREATHING
- # ifndef BACKLIGHT_CUSTOM_DRIVER
- # error "Backlight breathing only available with hardware PWM. Please disable."
- # endif
- # endif
- # else // hardware pwm through timer
- # 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) { FOR_EACH_LED(backlight_off(backlight_pin);) }
- // 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) {
- FOR_EACH_LED(backlight_on(backlight_pin);)
- }
- }
- # 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; }
- # ifndef BACKLIGHT_CUSTOM_DRIVER
- __attribute__((weak)) 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));
- FOR_EACH_LED(backlight_off(backlight_pin);)
- }
- # else
- // Turn off PWM control on backlight pin
- TCCRxA &= ~(_BV(COMxx1));
- # endif
- } else {
- # ifdef BACKLIGHT_PWM_TIMER
- if (!OCRxx) {
- TIMSKx |= _BV(OCIExA);
- TIMSKx |= _BV(TOIEx);
- }
- # else
- // Turn on PWM control of backlight pin
- TCCRxA |= _BV(COMxx1);
- # endif
- }
- // Set the brightness
- set_pwm(cie_lightness(TIMER_TOP * (uint32_t)level / BACKLIGHT_LEVELS));
- }
- void backlight_task(void) {}
- # endif // BACKLIGHT_CUSTOM_DRIVER
- # 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_period = BREATHING_PERIOD;
- 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 = 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;
- }
- void breathing_toggle(void) {
- if (is_breathing())
- breathing_disable();
- else
- breathing_enable();
- }
- void breathing_period_set(uint8_t value) {
- if (!value) value = 1;
- breathing_period = value;
- }
- void breathing_period_default(void) { breathing_period_set(BREATHING_PERIOD); }
- void breathing_period_inc(void) { breathing_period_set(breathing_period + 1); }
- void breathing_period_dec(void) { breathing_period_set(breathing_period - 1); }
- /* 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
- {
- 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
- __attribute__((weak)) void backlight_init_ports(void) {
- // Setup backlight pin as output and output to on state.
- FOR_EACH_LED(setPinOutput(backlight_pin); backlight_on(backlight_pin);)
- // 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
- // 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
- }
- # endif // hardware backlight
- #else // no backlight
- __attribute__((weak)) void backlight_init_ports(void) {}
- __attribute__((weak)) void backlight_set(uint8_t level) {}
- #endif // backlight
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