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[jackhill/qmk/firmware.git] / quantum / backlight / backlight_avr.c
1 #include "quantum.h"
2 #include "backlight.h"
3 #include "debug.h"
4
5 #if defined(BACKLIGHT_ENABLE) && (defined(BACKLIGHT_PIN) || defined(BACKLIGHT_PINS))
6
7 // This logic is a bit complex, we support 3 setups:
8 //
9 // 1. Hardware PWM when backlight is wired to a PWM pin.
10 // Depending on this pin, we use a different output compare unit.
11 // 2. Software PWM with hardware timers, but the used timer
12 // depends on the Audio setup (Audio wins over Backlight).
13 // 3. Full software PWM, driven by the matrix scan, if both timers are used by Audio.
14
15 # 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)
16 # define HARDWARE_PWM
17 # define ICRx ICR1
18 # define TCCRxA TCCR1A
19 # define TCCRxB TCCR1B
20 # define TIMERx_OVF_vect TIMER1_OVF_vect
21 # define TIMSKx TIMSK1
22 # define TOIEx TOIE1
23
24 # if BACKLIGHT_PIN == B5
25 # define COMxx0 COM1A0
26 # define COMxx1 COM1A1
27 # define OCRxx OCR1A
28 # elif BACKLIGHT_PIN == B6
29 # define COMxx0 COM1B0
30 # define COMxx1 COM1B1
31 # define OCRxx OCR1B
32 # elif BACKLIGHT_PIN == B7
33 # define COMxx0 COM1C0
34 # define COMxx1 COM1C1
35 # define OCRxx OCR1C
36 # endif
37 # 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)
38 # define HARDWARE_PWM
39 # define ICRx ICR3
40 # define TCCRxA TCCR3A
41 # define TCCRxB TCCR3B
42 # define TIMERx_OVF_vect TIMER3_OVF_vect
43 # define TIMSKx TIMSK3
44 # define TOIEx TOIE3
45
46 # if BACKLIGHT_PIN == C4
47 # if (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
48 # error This MCU has no C4 pin!
49 # else
50 # define COMxx0 COM3C0
51 # define COMxx1 COM3C1
52 # define OCRxx OCR3C
53 # endif
54 # elif BACKLIGHT_PIN == C5
55 # if (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
56 # error This MCU has no C5 pin!
57 # else
58 # define COMxx0 COM3B0
59 # define COMxx1 COM3B1
60 # define OCRxx OCR3B
61 # endif
62 # elif BACKLIGHT_PIN == C6
63 # define COMxx0 COM3A0
64 # define COMxx1 COM3A1
65 # define OCRxx OCR3A
66 # endif
67 # elif (defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__)) && (BACKLIGHT_PIN == B7 || BACKLIGHT_PIN == C5 || BACKLIGHT_PIN == C6)
68 # define HARDWARE_PWM
69 # define ICRx ICR1
70 # define TCCRxA TCCR1A
71 # define TCCRxB TCCR1B
72 # define TIMERx_OVF_vect TIMER1_OVF_vect
73 # define TIMSKx TIMSK1
74 # define TOIEx TOIE1
75
76 # if BACKLIGHT_PIN == B7
77 # define COMxx0 COM1C0
78 # define COMxx1 COM1C1
79 # define OCRxx OCR1C
80 # elif BACKLIGHT_PIN == C5
81 # define COMxx0 COM1B0
82 # define COMxx1 COM1B1
83 # define OCRxx OCR1B
84 # elif BACKLIGHT_PIN == C6
85 # define COMxx0 COM1A0
86 # define COMxx1 COM1A1
87 # define OCRxx OCR1A
88 # endif
89 # elif defined(__AVR_ATmega32A__) && (BACKLIGHT_PIN == D4 || BACKLIGHT_PIN == D5)
90 # define HARDWARE_PWM
91 # define ICRx ICR1
92 # define TCCRxA TCCR1A
93 # define TCCRxB TCCR1B
94 # define TIMERx_OVF_vect TIMER1_OVF_vect
95 # define TIMSKx TIMSK
96 # define TOIEx TOIE1
97
98 # if BACKLIGHT_PIN == D4
99 # define COMxx0 COM1B0
100 # define COMxx1 COM1B1
101 # define OCRxx OCR1B
102 # elif BACKLIGHT_PIN == D5
103 # define COMxx0 COM1A0
104 # define COMxx1 COM1A1
105 # define OCRxx OCR1A
106 # endif
107 # elif defined(__AVR_ATmega328P__) && (BACKLIGHT_PIN == B1 || BACKLIGHT_PIN == B2)
108 # define HARDWARE_PWM
109 # define ICRx ICR1
110 # define TCCRxA TCCR1A
111 # define TCCRxB TCCR1B
112 # define TIMERx_OVF_vect TIMER1_OVF_vect
113 # define TIMSKx TIMSK1
114 # define TOIEx TOIE1
115
116 # if BACKLIGHT_PIN == B1
117 # define COMxx0 COM1A0
118 # define COMxx1 COM1A1
119 # define OCRxx OCR1A
120 # elif BACKLIGHT_PIN == B2
121 # define COMxx0 COM1B0
122 # define COMxx1 COM1B1
123 # define OCRxx OCR1B
124 # endif
125 # else
126 # if !defined(BACKLIGHT_CUSTOM_DRIVER)
127 # if !defined(B5_AUDIO) && !defined(B6_AUDIO) && !defined(B7_AUDIO)
128 // Timer 1 is not in use by Audio feature, Backlight can use it
129 # pragma message "Using hardware timer 1 with software PWM"
130 # define HARDWARE_PWM
131 # define BACKLIGHT_PWM_TIMER
132 # define ICRx ICR1
133 # define TCCRxA TCCR1A
134 # define TCCRxB TCCR1B
135 # define TIMERx_COMPA_vect TIMER1_COMPA_vect
136 # define TIMERx_OVF_vect TIMER1_OVF_vect
137 # if defined(__AVR_ATmega32A__) // This MCU has only one TIMSK register
138 # define TIMSKx TIMSK
139 # else
140 # define TIMSKx TIMSK1
141 # endif
142 # define TOIEx TOIE1
143
144 # define OCIExA OCIE1A
145 # define OCRxx OCR1A
146 # elif !defined(C6_AUDIO) && !defined(C5_AUDIO) && !defined(C4_AUDIO)
147 # pragma message "Using hardware timer 3 with software PWM"
148 // Timer 3 is not in use by Audio feature, Backlight can use it
149 # define HARDWARE_PWM
150 # define BACKLIGHT_PWM_TIMER
151 # define ICRx ICR1
152 # define TCCRxA TCCR3A
153 # define TCCRxB TCCR3B
154 # define TIMERx_COMPA_vect TIMER3_COMPA_vect
155 # define TIMERx_OVF_vect TIMER3_OVF_vect
156 # define TIMSKx TIMSK3
157 # define TOIEx TOIE3
158
159 # define OCIExA OCIE3A
160 # define OCRxx OCR3A
161 # else
162 # pragma message "Audio in use - using pure software PWM"
163 # define NO_HARDWARE_PWM
164 # endif
165 # else
166 # pragma message "Custom driver defined - using pure software PWM"
167 # define NO_HARDWARE_PWM
168 # endif
169 # endif
170
171 # ifndef BACKLIGHT_ON_STATE
172 # define BACKLIGHT_ON_STATE 1
173 # endif
174
175 void backlight_on(pin_t backlight_pin) {
176 # if BACKLIGHT_ON_STATE == 1
177 writePinHigh(backlight_pin);
178 # else
179 writePinLow(backlight_pin);
180 # endif
181 }
182
183 void backlight_off(pin_t backlight_pin) {
184 # if BACKLIGHT_ON_STATE == 1
185 writePinLow(backlight_pin);
186 # else
187 writePinHigh(backlight_pin);
188 # endif
189 }
190
191 # if defined(NO_HARDWARE_PWM) || defined(BACKLIGHT_PWM_TIMER) // pwm through software
192
193 // we support multiple backlight pins
194 # ifndef BACKLIGHT_LED_COUNT
195 # define BACKLIGHT_LED_COUNT 1
196 # endif
197
198 # if BACKLIGHT_LED_COUNT == 1
199 # define BACKLIGHT_PIN_INIT \
200 { BACKLIGHT_PIN }
201 # else
202 # define BACKLIGHT_PIN_INIT BACKLIGHT_PINS
203 # endif
204
205 # define FOR_EACH_LED(x) \
206 for (uint8_t i = 0; i < BACKLIGHT_LED_COUNT; i++) { \
207 pin_t backlight_pin = backlight_pins[i]; \
208 { x } \
209 }
210
211 static const pin_t backlight_pins[BACKLIGHT_LED_COUNT] = BACKLIGHT_PIN_INIT;
212
213 # else // full hardware PWM
214
215 static inline void enable_pwm(void) {
216 # if BACKLIGHT_ON_STATE == 1
217 TCCRxA |= _BV(COMxx1);
218 # else
219 TCCRxA |= _BV(COMxx1) | _BV(COMxx0);
220 # endif
221 }
222
223 static inline void disable_pwm(void) {
224 # if BACKLIGHT_ON_STATE == 1
225 TCCRxA &= ~(_BV(COMxx1));
226 # else
227 TCCRxA &= ~(_BV(COMxx1) | _BV(COMxx0));
228 # endif
229 }
230
231 // we support only one backlight pin
232 static const pin_t backlight_pin = BACKLIGHT_PIN;
233 # define FOR_EACH_LED(x) x
234
235 # endif
236
237 # ifdef NO_HARDWARE_PWM
238 void backlight_init_ports(void) {
239 // Setup backlight pin as output and output to on state.
240 FOR_EACH_LED(setPinOutput(backlight_pin); backlight_on(backlight_pin);)
241
242 # ifdef BACKLIGHT_BREATHING
243 if (is_backlight_breathing()) {
244 breathing_enable();
245 }
246 # endif
247 }
248
249 uint8_t backlight_tick = 0;
250
251 # ifndef BACKLIGHT_CUSTOM_DRIVER
252 void backlight_task(void) {
253 if ((0xFFFF >> ((BACKLIGHT_LEVELS - get_backlight_level()) * ((BACKLIGHT_LEVELS + 1) / 2))) & (1 << backlight_tick)) {
254 FOR_EACH_LED(backlight_on(backlight_pin);)
255 } else {
256 FOR_EACH_LED(backlight_off(backlight_pin);)
257 }
258 backlight_tick = (backlight_tick + 1) % 16;
259 }
260 # endif
261
262 # ifdef BACKLIGHT_BREATHING
263 # ifndef BACKLIGHT_CUSTOM_DRIVER
264 # error "Backlight breathing only available with hardware PWM. Please disable."
265 # endif
266 # endif
267
268 # else // hardware pwm through timer
269
270 # ifdef BACKLIGHT_PWM_TIMER
271
272 // The idea of software PWM assisted by hardware timers is the following
273 // we use the hardware timer in fast PWM mode like for hardware PWM, but
274 // instead of letting the Output Match Comparator control the led pin
275 // (which is not possible since the backlight is not wired to PWM pins on the
276 // CPU), we do the LED on/off by oursleves.
277 // The timer is setup to count up to 0xFFFF, and we set the Output Compare
278 // register to the current 16bits backlight level (after CIE correction).
279 // This means the CPU will trigger a compare match interrupt when the counter
280 // reaches the backlight level, where we turn off the LEDs,
281 // but also an overflow interrupt when the counter rolls back to 0,
282 // in which we're going to turn on the LEDs.
283 // The LED will then be on for OCRxx/0xFFFF time, adjusted every 244Hz.
284
285 // Triggered when the counter reaches the OCRx value
286 ISR(TIMERx_COMPA_vect) { FOR_EACH_LED(backlight_off(backlight_pin);) }
287
288 // Triggered when the counter reaches the TOP value
289 // this one triggers at F_CPU/65536 =~ 244 Hz
290 ISR(TIMERx_OVF_vect) {
291 # ifdef BACKLIGHT_BREATHING
292 if (is_breathing()) {
293 breathing_task();
294 }
295 # endif
296 // for very small values of OCRxx (or backlight level)
297 // we can't guarantee this whole code won't execute
298 // at the same time as the compare match interrupt
299 // which means that we might turn on the leds while
300 // trying to turn them off, leading to flickering
301 // artifacts (especially while breathing, because breathing_task
302 // takes many computation cycles).
303 // so better not turn them on while the counter TOP is very low.
304 if (OCRxx > 256) {
305 FOR_EACH_LED(backlight_on(backlight_pin);)
306 }
307 }
308
309 # endif
310
311 # define TIMER_TOP 0xFFFFU
312
313 // See http://jared.geek.nz/2013/feb/linear-led-pwm
314 static uint16_t cie_lightness(uint16_t v) {
315 if (v <= 5243) // if below 8% of max
316 return v / 9; // same as dividing by 900%
317 else {
318 uint32_t y = (((uint32_t)v + 10486) << 8) / (10486 + 0xFFFFUL); // add 16% of max and compare
319 // to get a useful result with integer division, we shift left in the expression above
320 // and revert what we've done again after squaring.
321 y = y * y * y >> 8;
322 if (y > 0xFFFFUL) // prevent overflow
323 return 0xFFFFU;
324 else
325 return (uint16_t)y;
326 }
327 }
328
329 // range for val is [0..TIMER_TOP]. PWM pin is high while the timer count is below val.
330 static inline void set_pwm(uint16_t val) { OCRxx = val; }
331
332 # ifndef BACKLIGHT_CUSTOM_DRIVER
333 void backlight_set(uint8_t level) {
334 if (level > BACKLIGHT_LEVELS) level = BACKLIGHT_LEVELS;
335
336 if (level == 0) {
337 # ifdef BACKLIGHT_PWM_TIMER
338 if (OCRxx) {
339 TIMSKx &= ~(_BV(OCIExA));
340 TIMSKx &= ~(_BV(TOIEx));
341 }
342 # else
343 // Turn off PWM control on backlight pin
344 disable_pwm();
345 # endif
346 FOR_EACH_LED(backlight_off(backlight_pin);)
347 } else {
348 # ifdef BACKLIGHT_PWM_TIMER
349 if (!OCRxx) {
350 TIMSKx |= _BV(OCIExA);
351 TIMSKx |= _BV(TOIEx);
352 }
353 # else
354 // Turn on PWM control of backlight pin
355 enable_pwm();
356 # endif
357 }
358 // Set the brightness
359 set_pwm(cie_lightness(TIMER_TOP * (uint32_t)level / BACKLIGHT_LEVELS));
360 }
361
362 void backlight_task(void) {}
363 # endif // BACKLIGHT_CUSTOM_DRIVER
364
365 # ifdef BACKLIGHT_BREATHING
366
367 # define BREATHING_NO_HALT 0
368 # define BREATHING_HALT_OFF 1
369 # define BREATHING_HALT_ON 2
370 # define BREATHING_STEPS 128
371
372 static uint8_t breathing_halt = BREATHING_NO_HALT;
373 static uint16_t breathing_counter = 0;
374
375 # ifdef BACKLIGHT_PWM_TIMER
376 static bool breathing = false;
377
378 bool is_breathing(void) { return breathing; }
379
380 # define breathing_interrupt_enable() \
381 do { \
382 breathing = true; \
383 } while (0)
384 # define breathing_interrupt_disable() \
385 do { \
386 breathing = false; \
387 } while (0)
388 # else
389
390 bool is_breathing(void) { return !!(TIMSKx & _BV(TOIEx)); }
391
392 # define breathing_interrupt_enable() \
393 do { \
394 TIMSKx |= _BV(TOIEx); \
395 } while (0)
396 # define breathing_interrupt_disable() \
397 do { \
398 TIMSKx &= ~_BV(TOIEx); \
399 } while (0)
400 # endif
401
402 # define breathing_min() \
403 do { \
404 breathing_counter = 0; \
405 } while (0)
406 # define breathing_max() \
407 do { \
408 breathing_counter = get_breathing_period() * 244 / 2; \
409 } while (0)
410
411 void breathing_enable(void) {
412 breathing_counter = 0;
413 breathing_halt = BREATHING_NO_HALT;
414 breathing_interrupt_enable();
415 }
416
417 void breathing_pulse(void) {
418 if (get_backlight_level() == 0)
419 breathing_min();
420 else
421 breathing_max();
422 breathing_halt = BREATHING_HALT_ON;
423 breathing_interrupt_enable();
424 }
425
426 void breathing_disable(void) {
427 breathing_interrupt_disable();
428 // Restore backlight level
429 backlight_set(get_backlight_level());
430 }
431
432 void breathing_self_disable(void) {
433 if (get_backlight_level() == 0)
434 breathing_halt = BREATHING_HALT_OFF;
435 else
436 breathing_halt = BREATHING_HALT_ON;
437 }
438
439 void breathing_toggle(void) {
440 if (is_breathing())
441 breathing_disable();
442 else
443 breathing_enable();
444 }
445
446 /* To generate breathing curve in python:
447 * from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)]
448 */
449 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};
450
451 // Use this before the cie_lightness function.
452 static inline uint16_t scale_backlight(uint16_t v) { return v / BACKLIGHT_LEVELS * get_backlight_level(); }
453
454 # ifdef BACKLIGHT_PWM_TIMER
455 void breathing_task(void)
456 # else
457 /* Assuming a 16MHz CPU clock and a timer that resets at 64k (ICR1), the following interrupt handler will run
458 * about 244 times per second.
459 */
460 ISR(TIMERx_OVF_vect)
461 # endif
462 {
463 uint8_t breathing_period = get_breathing_period();
464 uint16_t interval = (uint16_t)breathing_period * 244 / BREATHING_STEPS;
465 // resetting after one period to prevent ugly reset at overflow.
466 breathing_counter = (breathing_counter + 1) % (breathing_period * 244);
467 uint8_t index = breathing_counter / interval % BREATHING_STEPS;
468
469 if (((breathing_halt == BREATHING_HALT_ON) && (index == BREATHING_STEPS / 2)) || ((breathing_halt == BREATHING_HALT_OFF) && (index == BREATHING_STEPS - 1))) {
470 breathing_interrupt_disable();
471 }
472
473 set_pwm(cie_lightness(scale_backlight((uint16_t)pgm_read_byte(&breathing_table[index]) * 0x0101U)));
474 }
475
476 # endif // BACKLIGHT_BREATHING
477
478 void backlight_init_ports(void) {
479 // Setup backlight pin as output and output to on state.
480 FOR_EACH_LED(setPinOutput(backlight_pin); backlight_on(backlight_pin);)
481
482 // I could write a wall of text here to explain... but TL;DW
483 // Go read the ATmega32u4 datasheet.
484 // And this: http://blog.saikoled.com/post/43165849837/secret-konami-cheat-code-to-high-resolution-pwm-on
485
486 # ifdef BACKLIGHT_PWM_TIMER
487 // TimerX setup, Fast PWM mode count to TOP set in ICRx
488 TCCRxA = _BV(WGM11); // = 0b00000010;
489 // clock select clk/1
490 TCCRxB = _BV(WGM13) | _BV(WGM12) | _BV(CS10); // = 0b00011001;
491 # else // hardware PWM
492 // Pin PB7 = OCR1C (Timer 1, Channel C)
493 // Compare Output Mode = Clear on compare match, Channel C = COM1C1=1 COM1C0=0
494 // (i.e. start high, go low when counter matches.)
495 // WGM Mode 14 (Fast PWM) = WGM13=1 WGM12=1 WGM11=1 WGM10=0
496 // Clock Select = clk/1 (no prescaling) = CS12=0 CS11=0 CS10=1
497
498 /*
499 14.8.3:
500 "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 [..]."
501 "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)."
502 */
503 # if BACKLIGHT_ON_STATE == 1
504 TCCRxA = _BV(COMxx1) | _BV(WGM11);
505 # else
506 TCCRxA = _BV(COMxx1) | _BV(COMxx0) | _BV(WGM11);
507 # endif
508
509 TCCRxB = _BV(WGM13) | _BV(WGM12) | _BV(CS10);
510 # endif
511 // Use full 16-bit resolution. Counter counts to ICR1 before reset to 0.
512 ICRx = TIMER_TOP;
513
514 backlight_init();
515 # ifdef BACKLIGHT_BREATHING
516 if (is_backlight_breathing()) {
517 breathing_enable();
518 }
519 # endif
520 }
521
522 # endif // hardware backlight
523
524 #endif // backlight
QMK Keyboard Firmware