1 /*
2 * Generic GPIO led
3 *
4 * Copyright (C) 2019 - 2020 Andy Green <andy@warmcat.com>
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 * IN THE SOFTWARE.
23 */
24 #include "private-lib-core.h"
25
26 static const lws_led_intensity_t sineq16[] = {
27
28 /*
29 * Quadrant at sin(270) in 16 samples, normalized so
30 * -1 == 0 and 0 == 32767
31 */
32
33 0, 158, 630, 1411, 2494, 3869, 5522, 7437,
34 9597, 11980, 14562, 17321, 20228, 23225, 26374, 29555,
35 32767 /* to interpolate against */
36 };
37
38 /*
39 * Elaborate the 90 degree phase table to 360 degrees and offset to +32768,
40 * notice for the last sample we have to interpolate against a 17th sample
41 * reflecting full scale to avoid clipping due to interpolation against the
42 * 16th sample again
43 */
44
45 static lws_led_intensity_t
sine_lu(int n,int next)46 sine_lu(int n, int next)
47 {
48 switch ((n >> 4) & 3) {
49 case 1:
50 /* forwards */
51 return 32768 + sineq16[(n & 15) + next];
52 case 2:
53 /* scan it backwards */
54 return 32768 + sineq16[15 - (n & 15) + (!next)];
55 case 3:
56 /* forwards */
57 return 32768 - sineq16[(n & 15) + next];
58 default:
59 /* scan it backwards */
60 return 32768 - sineq16[15 - (n & 15) + (!next)];
61 }
62 }
63
64 /*
65 * The normalized phase resolution is 16-bit, however much table you decide to
66 * have needs interpolating or indexing in a reduced number of significant
67 * phase bits if it doesn't have the same phase resolution.
68 *
69 * In this sine table we have a 16 x 15-bit sample quadrant reflected 4 times
70 * to make 360 degrees, so 64 accurate sample points, with the rest of the
71 * intermediate phases generated by linear interpolation. That probably would
72 * sound a bit funky, but for modulating light dynamically it's more than
73 * enough.
74 */
75
76 lws_led_intensity_t
lws_led_func_sine(lws_led_seq_phase_t n)77 lws_led_func_sine(lws_led_seq_phase_t n)
78 {
79 /*
80 * 2: quadrant
81 * 4: table entry in quadrant
82 * 10: interp (LSB)
83 */
84
85 return (sine_lu(n >> 10, 0) * (0x3ff - (n & 0x3ff)) +
86 sine_lu(n >> 10, 1) * (n & 0x3ff)) / 0x3ff;
87 }
88
89 lws_led_intensity_t
lws_led_func_linear(lws_led_seq_phase_t n)90 lws_led_func_linear(lws_led_seq_phase_t n)
91 {
92 return (lws_led_intensity_t)n;
93 }
94
95
96 static lws_led_intensity_t
lws_led_func_static(lws_led_seq_phase_t n)97 lws_led_func_static(lws_led_seq_phase_t n)
98 {
99 return ((int)n * LWS_LED_MAX_INTENSITY) / 2;
100 }
101
102 const lws_led_sequence_def_t lws_pwmseq_static_off = {
103 .func = lws_led_func_static,
104 .ledphase_offset = 0,
105 .ledphase_total = 0,
106 .ms = 0
107 };
108
109 const lws_led_sequence_def_t lws_pwmseq_static_half = {
110 .func = lws_led_func_static,
111 .ledphase_offset = 1,
112 .ledphase_total = 0,
113 .ms = 0
114 };
115
116 const lws_led_sequence_def_t lws_pwmseq_static_on = {
117 .func = lws_led_func_static,
118 .ledphase_offset = 2,
119 .ledphase_total = 0,
120 .ms = 0
121 };
122
123 const lws_led_sequence_def_t lws_pwmseq_sine_up = {
124 .func = lws_led_func_sine,
125 .ledphase_offset = 0, /* already at 0 amp at 0 phase */
126 .ledphase_total = LWS_LED_FUNC_PHASE / 2, /* 180 degree ./^ */
127 .ms = 300
128 };
129
130 const lws_led_sequence_def_t lws_pwmseq_sine_down = {
131 .func = lws_led_func_sine,
132 .ledphase_offset = LWS_LED_FUNC_PHASE / 2, /* start at peak */
133 .ledphase_total = LWS_LED_FUNC_PHASE / 2, /* 180 degree ./^ */
134 .ms = 300
135 };
136
137 const lws_led_sequence_def_t lws_pwmseq_linear_wipe = {
138 .func = lws_led_func_linear,
139 .ledphase_offset = 0,
140 .ledphase_total = LWS_LED_FUNC_PHASE - 1,
141 .ms = 300
142 };
143
144 const lws_led_sequence_def_t lws_pwmseq_sine_endless_slow = {
145 .func = lws_led_func_sine,
146 .ledphase_offset = 0, /* already at 0 amp at 0 phase */
147 .ledphase_total = LWS_SEQ_LEDPHASE_TOTAL_ENDLESS,
148 .ms = 1500
149 };
150
151 const lws_led_sequence_def_t lws_pwmseq_sine_endless_fast = {
152 .func = lws_led_func_sine,
153 .ledphase_offset = 0, /* already at 0 amp at 0 phase */
154 .ledphase_total = LWS_SEQ_LEDPHASE_TOTAL_ENDLESS,
155 .ms = 750
156 };
157