core: Fix sleep_led
[tmk_keyboard.git] / tmk_core / common / avr / sleep_led.c
1 #include <stdint.h>
2 #include <avr/io.h>
3 #include <avr/interrupt.h>
4 #include <avr/pgmspace.h>
5 #include "led.h"
6 #include "sleep_led.h"
7
8 /* Software PWM
9 * ______ ______ __
10 * | ON |___OFF___| ON |___OFF___| ....
11 * |<-------------->|<-------------->|<- ....
12 * PWM period PWM period
13 *
14 * 256 interrupts/period[resolution]
15 * 64 periods/second[frequency]
16 * 256*64 interrupts/second
17 * F_CPU/(256*64) clocks/interrupt
18 */
19 #define SLEEP_LED_TIMER_TOP F_CPU/(256*64)
20
21 void sleep_led_init(void)
22 {
23 /* Timer1 setup */
24 /* CTC mode */
25 TCCR1B |= _BV(WGM12);
26 /* Clock selelct: clk/1 */
27 TCCR1B |= _BV(CS10);
28 /* Set TOP value */
29 uint8_t sreg = SREG;
30 cli();
31 OCR1AH = (SLEEP_LED_TIMER_TOP>>8)&0xff;
32 OCR1AL = SLEEP_LED_TIMER_TOP&0xff;
33 SREG = sreg;
34 }
35
36 void sleep_led_enable(void)
37 {
38 /* Enable Compare Match Interrupt */
39 TIMSK1 |= _BV(OCIE1A);
40 }
41
42 void sleep_led_disable(void)
43 {
44 /* Disable Compare Match Interrupt */
45 TIMSK1 &= ~_BV(OCIE1A);
46 }
47
48
49 __attribute__ ((weak))
50 void sleep_led_on(void)
51 {
52 led_set(1<<USB_LED_CAPS_LOCK);
53 }
54
55 __attribute__ ((weak))
56 void sleep_led_off(void)
57 {
58 led_set(0);
59 }
60
61
62 /* Breathing Sleep LED brighness(PWM On period) table
63 * (64[steps] * 4[duration]) / 64[PWM periods/s] = 4 second breath cycle
64 *
65 * http://www.wolframalpha.com/input/?i=%28sin%28+x%2F64*pi%29**8+*+255%2C+x%3D0+to+63
66 * (0..63).each {|x| p ((sin(x/64.0*PI)**8)*255).to_i }
67 */
68 static const uint8_t breathing_table[64] PROGMEM = {
69 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 4, 6, 10,
70 15, 23, 32, 44, 58, 74, 93, 113, 135, 157, 179, 199, 218, 233, 245, 252,
71 255, 252, 245, 233, 218, 199, 179, 157, 135, 113, 93, 74, 58, 44, 32, 23,
72 15, 10, 6, 4, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
73 };
74
75 ISR(TIMER1_COMPA_vect)
76 {
77 /* Software PWM
78 * timer:1111 1111 1111 1111
79 * \_____/\/ \_______/____ count(0-255)
80 * \ \______________ duration of step(4)
81 * \__________________ index of step table(0-63)
82 */
83 static union {
84 uint16_t row;
85 struct {
86 uint8_t count:8;
87 uint8_t duration:2;
88 uint8_t index:6;
89 } pwm;
90 } timer = { .row = 0 };
91
92 timer.row++;
93
94 // LED on
95 if (timer.pwm.count == 0) {
96 sleep_led_on();
97 }
98 // LED off
99 if (timer.pwm.count == pgm_read_byte(&breathing_table[timer.pwm.index])) {
100 sleep_led_off();
101 }
102 }
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