1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
#include "quantum.h"
#include "backlight.h"
#include <hal.h>
#include "debug.h"
// Maximum duty cycle limit
#ifndef BACKLIGHT_LIMIT_VAL
# define BACKLIGHT_LIMIT_VAL 255
#endif
#ifndef BACKLIGHT_PAL_MODE
# if defined(USE_GPIOV1)
# define BACKLIGHT_PAL_MODE PAL_MODE_ALTERNATE_PUSHPULL
# else
// GPIOV2 && GPIOV3
# define BACKLIGHT_PAL_MODE 5
# endif
#endif
// GENERIC
#ifndef BACKLIGHT_PWM_DRIVER
# define BACKLIGHT_PWM_DRIVER PWMD4
#endif
#ifndef BACKLIGHT_PWM_CHANNEL
# define BACKLIGHT_PWM_CHANNEL 3
#endif
// Support for pins which are on TIM1_CH1N - requires STM32_PWM_USE_ADVANCED
#ifdef BACKLIGHT_PWM_COMPLEMENTARY_OUTPUT
# if BACKLIGHT_ON_STATE == 1
# define PWM_OUTPUT_MODE PWM_COMPLEMENTARY_OUTPUT_ACTIVE_LOW;
# else
# define PWM_OUTPUT_MODE PWM_COMPLEMENTARY_OUTPUT_ACTIVE_HIGH;
# endif
#else
# if BACKLIGHT_ON_STATE == 1
# define PWM_OUTPUT_MODE PWM_OUTPUT_ACTIVE_HIGH;
# else
# define PWM_OUTPUT_MODE PWM_OUTPUT_ACTIVE_LOW;
# endif
#endif
#ifndef BACKLIGHT_PWM_COUNTER_FREQUENCY
# define BACKLIGHT_PWM_COUNTER_FREQUENCY 0xFFFF
#endif
#ifndef BACKLIGHT_PWM_PERIOD
# define BACKLIGHT_PWM_PERIOD 256
#endif
static PWMConfig pwmCFG = {
.frequency = BACKLIGHT_PWM_COUNTER_FREQUENCY, /* PWM clock frequency */
.period = BACKLIGHT_PWM_PERIOD, /* PWM period in counter ticks. e.g. clock frequency is 10KHz, period is 256 ticks then t_period is 25.6ms */
};
#ifdef BACKLIGHT_BREATHING
static virtual_timer_t breathing_vt;
#endif
// 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;
}
}
}
static uint32_t rescale_limit_val(uint32_t val) {
// rescale the supplied backlight value to be in terms of the value limit
return (val * (BACKLIGHT_LIMIT_VAL + 1)) / 256;
}
void backlight_init_ports(void) {
#ifdef USE_GPIOV1
palSetPadMode(PAL_PORT(BACKLIGHT_PIN), PAL_PAD(BACKLIGHT_PIN), BACKLIGHT_PAL_MODE);
#else
palSetPadMode(PAL_PORT(BACKLIGHT_PIN), PAL_PAD(BACKLIGHT_PIN), PAL_MODE_ALTERNATE(BACKLIGHT_PAL_MODE));
#endif
pwmCFG.channels[BACKLIGHT_PWM_CHANNEL - 1].mode = PWM_OUTPUT_MODE;
pwmStart(&BACKLIGHT_PWM_DRIVER, &pwmCFG);
backlight_set(get_backlight_level());
#ifdef BACKLIGHT_BREATHING
chVTObjectInit(&breathing_vt);
if (is_backlight_breathing()) {
breathing_enable();
}
#endif
}
void backlight_set(uint8_t level) {
if (level > BACKLIGHT_LEVELS) {
level = BACKLIGHT_LEVELS;
}
if (level == 0) {
// Turn backlight off
pwmDisableChannel(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1);
} else {
// Turn backlight on
uint32_t duty = (uint32_t)(cie_lightness(rescale_limit_val(0xFFFF * (uint32_t)level / BACKLIGHT_LEVELS)));
pwmEnableChannel(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));
}
}
void backlight_task(void) {}
#ifdef BACKLIGHT_BREATHING
# define BREATHING_STEPS 128
/* 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] = {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};
static void breathing_callback(virtual_timer_t *vtp, void *p);
bool is_breathing(void) {
return chVTIsArmed(&breathing_vt);
}
void breathing_enable(void) {
/* Update frequency is 256Hz -> 3906us intervals */
chVTSetContinuous(&breathing_vt, TIME_US2I(3906), breathing_callback, NULL);
}
void breathing_disable(void) {
chVTReset(&breathing_vt);
// Restore backlight level
backlight_set(get_backlight_level());
}
// Use this before the cie_lightness function.
static inline uint16_t scale_backlight(uint16_t v) {
return v / BACKLIGHT_LEVELS * get_backlight_level();
}
static void breathing_callback(virtual_timer_t *vtp, void *p) {
uint8_t breathing_period = get_breathing_period();
uint16_t interval = (uint16_t)breathing_period * 256 / BREATHING_STEPS;
// resetting after one period to prevent ugly reset at overflow.
static uint16_t breathing_counter = 0;
breathing_counter = (breathing_counter + 1) % (breathing_period * 256);
uint8_t index = breathing_counter / interval % BREATHING_STEPS;
uint32_t duty = cie_lightness(rescale_limit_val(scale_backlight(breathing_table[index] * 256)));
chSysLockFromISR();
pwmEnableChannelI(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));
chSysUnlockFromISR();
}
// TODO: integrate generic pulse solution
void breathing_pulse(void) {
backlight_set(is_backlight_enabled() ? 0 : BACKLIGHT_LEVELS);
wait_ms(10);
backlight_set(is_backlight_enabled() ? get_backlight_level() : 0);
}
#endif
|
