2 Copyright 2012 Jun Wako <wakojun@gmail.com>
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>.
19 #include "led_custom.h"
23 static void breathing_callback(PWMDriver *pwmp);
25 static PWMConfig pwmCFG = {
26 0xFFFF, /* PWM clock frequency */
27 256, /* PWM period (in ticks) 1S (1/10kHz=0.1mS 0.1ms*10000 ticks=1S) */
28 NULL, /* No Callback */
30 {PWM_OUTPUT_DISABLED, NULL},
31 {PWM_OUTPUT_DISABLED, NULL},
32 {PWM_OUTPUT_ACTIVE_HIGH, NULL}, /* Enable Channel 3 */
33 {PWM_OUTPUT_DISABLED, NULL}
35 0, /* HW dependent part.*/
39 static PWMConfig pwmCFG_breathing = {
40 0xFFFF, /* 10kHz PWM clock frequency */
41 256, /* PWM period (in ticks) 1S (1/10kHz=0.1mS 0.1ms*10000 ticks=1S) */
42 breathing_callback, /* Breathing Callback */
44 {PWM_OUTPUT_DISABLED, NULL},
45 {PWM_OUTPUT_DISABLED, NULL},
46 {PWM_OUTPUT_ACTIVE_HIGH, NULL}, /* Enable Channel 3 */
47 {PWM_OUTPUT_DISABLED, NULL}
49 0, /* HW dependent part.*/
53 // See http://jared.geek.nz/2013/feb/linear-led-pwm
54 static uint16_t cie_lightness(uint16_t v) {
55 if (v <= 5243) // if below 8% of max
56 return v / 9; // same as dividing by 900%
58 uint32_t y = (((uint32_t)v + 10486) << 8) / (10486 + 0xFFFFUL); // add 16% of max and compare
59 // to get a useful result with integer division, we shift left in the expression above
60 // and revert what we've done again after squaring.
62 if (y > 0xFFFFUL) // prevent overflow
69 void backlight_init_ports(void) {
70 palSetPadMode(GPIOB, 8, PAL_MODE_ALTERNATE(2));
71 pwmStart(&PWMD4, &pwmCFG);
72 if (kb_backlight_config.enable) {
73 if (kb_backlight_config.breathing) {
76 backlight_set(kb_backlight_config.level);
83 void backlight_set(uint8_t level) {
84 uint32_t duty = (uint32_t)(cie_lightness(0xFFFF * (uint32_t)level / BACKLIGHT_LEVELS));
87 // Disable channel 3 on PWM4
88 pwmDisableChannel(&PWMD4, 2);
91 if (!is_breathing()) {
92 // Enable channel 3 on PWM4
93 pwmEnableChannel(&PWMD4, 2, PWM_FRACTION_TO_WIDTH(&PWMD4, 0xFFFF, duty));
98 uint8_t backlight_tick = 0;
100 void backlight_task(void) {
103 #define BREATHING_NO_HALT 0
104 #define BREATHING_HALT_OFF 1
105 #define BREATHING_HALT_ON 2
106 #define BREATHING_STEPS 128
108 static uint8_t breathing_period = BREATHING_PERIOD;
109 static uint8_t breathing_halt = BREATHING_NO_HALT;
110 static uint16_t breathing_counter = 0;
112 bool is_breathing(void) {
113 return PWMD4.config == &pwmCFG_breathing;
116 #define breathing_min() do {breathing_counter = 0;} while (0)
117 #define breathing_max() do {breathing_counter = breathing_period * 256 / 2;} while (0)
120 void breathing_interrupt_enable(void){
122 pwmStart(&PWMD4, &pwmCFG_breathing);
124 pwmEnablePeriodicNotification(&PWMD4);
128 PWM_FRACTION_TO_WIDTH(
134 chSysUnlockFromISR();
137 void breathing_interrupt_disable(void){
139 pwmStart(&PWMD4, &pwmCFG);
142 void breathing_enable(void)
144 breathing_counter = 0;
145 breathing_halt = BREATHING_NO_HALT;
146 breathing_interrupt_enable();
149 void breathing_pulse(void)
151 if (kb_backlight_config.level == 0)
155 breathing_halt = BREATHING_HALT_ON;
156 breathing_interrupt_enable();
159 void breathing_disable(void)
161 breathing_interrupt_disable();
162 // Restore backlight level
163 backlight_set(kb_backlight_config.level);
166 void breathing_self_disable(void)
168 if (kb_backlight_config.level == 0)
169 breathing_halt = BREATHING_HALT_OFF;
171 breathing_halt = BREATHING_HALT_ON;
174 void breathing_toggle(void) {
182 void breathing_period_set(uint8_t value)
186 breathing_period = value;
189 void breathing_period_default(void) {
190 breathing_period_set(BREATHING_PERIOD);
193 void breathing_period_inc(void)
195 breathing_period_set(breathing_period+1);
198 void breathing_period_dec(void)
200 breathing_period_set(breathing_period-1);
203 /* To generate breathing curve in python:
204 * from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)]
206 static const uint8_t breathing_table[BREATHING_STEPS] = {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};
208 // Use this before the cie_lightness function.
209 static inline uint16_t scale_backlight(uint16_t v) {
210 return v / BACKLIGHT_LEVELS * kb_backlight_config.level;
213 static void breathing_callback(PWMDriver *pwmp)
216 uint16_t interval = (uint16_t) breathing_period * 256 / BREATHING_STEPS;
217 // resetting after one period to prevent ugly reset at overflow.
218 breathing_counter = (breathing_counter + 1) % (breathing_period * 256);
219 uint8_t index = breathing_counter / interval % BREATHING_STEPS;
221 if (((breathing_halt == BREATHING_HALT_ON) && (index == BREATHING_STEPS / 2)) ||
222 ((breathing_halt == BREATHING_HALT_OFF) && (index == BREATHING_STEPS - 1)))
224 breathing_interrupt_disable();
227 uint32_t duty = cie_lightness(scale_backlight(breathing_table[index] * 256));
233 PWM_FRACTION_TO_WIDTH(
239 chSysUnlockFromISR();