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66fc6e7c UH |
1 | ## |
2 | ## This file is part of the libsigrokdecode project. | |
3 | ## | |
4 | ## Copyright (C) 2016 Vladimir Ermakov <vooon341@gmail.com> | |
5 | ## | |
6 | ## This program is free software; you can redistribute it and/or modify | |
7 | ## it under the terms of the GNU General Public License as published by | |
8 | ## the Free Software Foundation; either version 3 of the License, or | |
9 | ## (at your option) any later version. | |
10 | ## | |
11 | ## This program is distributed in the hope that it will be useful, | |
12 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | ## GNU General Public License for more details. | |
15 | ## | |
16 | ## You should have received a copy of the GNU General Public License | |
4539e9ca | 17 | ## along with this program; if not, see <http://www.gnu.org/licenses/>. |
66fc6e7c UH |
18 | ## |
19 | ||
20 | import sigrokdecode as srd | |
6d1cde1d | 21 | from common.srdhelper import bitpack_msb |
66fc6e7c UH |
22 | |
23 | class SamplerateError(Exception): | |
24 | pass | |
25 | ||
0e3c3498 GS |
26 | ( ANN_BIT, ANN_RESET, ANN_RGB, ) = range(3) |
27 | ||
66fc6e7c | 28 | class Decoder(srd.Decoder): |
7a85bbbe | 29 | api_version = 3 |
66fc6e7c UH |
30 | id = 'rgb_led_ws281x' |
31 | name = 'RGB LED (WS281x)' | |
32 | longname = 'RGB LED string decoder (WS281x)' | |
33 | desc = 'RGB LED string protocol (WS281x).' | |
34 | license = 'gplv3+' | |
35 | inputs = ['logic'] | |
6cbba91f | 36 | outputs = [] |
2787cf2a | 37 | tags = ['Display', 'IC'] |
66fc6e7c UH |
38 | channels = ( |
39 | {'id': 'din', 'name': 'DIN', 'desc': 'DIN data line'}, | |
40 | ) | |
41 | annotations = ( | |
42 | ('bit', 'Bit'), | |
43 | ('reset', 'RESET'), | |
44 | ('rgb', 'RGB'), | |
45 | ) | |
46 | annotation_rows = ( | |
0e3c3498 GS |
47 | ('bits', 'Bits', (ANN_BIT, ANN_RESET,)), |
48 | ('rgb-vals', 'RGB values', (ANN_RGB,)), | |
66fc6e7c | 49 | ) |
47ff9910 S |
50 | options = ( |
51 | {'id': 'type', 'desc': 'RGB or RGBW', 'default': 'RGB', | |
52 | 'values': ('RGB', 'RGBW')}, | |
53 | ) | |
66fc6e7c | 54 | |
92b7b49f | 55 | def __init__(self): |
10aeb8ea GS |
56 | self.reset() |
57 | ||
58 | def reset(self): | |
66fc6e7c | 59 | self.samplerate = None |
66fc6e7c | 60 | self.bits = [] |
66fc6e7c UH |
61 | |
62 | def start(self): | |
63 | self.out_ann = self.register(srd.OUTPUT_ANN) | |
64 | ||
65 | def metadata(self, key, value): | |
66 | if key == srd.SRD_CONF_SAMPLERATE: | |
67 | self.samplerate = value | |
68 | ||
192a9e78 GS |
69 | def putg(self, ss, es, cls, text): |
70 | self.put(ss, es, self.out_ann, [cls, text]) | |
71 | ||
6d1cde1d GS |
72 | def handle_bits(self): |
73 | if len(self.bits) < self.need_bits: | |
74 | return | |
75 | grb = bitpack_msb(self.bits, 0) | |
47ff9910 | 76 | if self.options['type'] == 'RGB': |
6d1cde1d GS |
77 | rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0x0000ff) |
78 | text = '#{:06x}'.format(rgb) | |
47ff9910 | 79 | else: |
6d1cde1d GS |
80 | rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0xff0000ff) |
81 | text = '#{:08x}'.format(rgb) | |
82 | ss_packet, es_packet = self.bits[0][1], self.bits[-1][2] | |
83 | self.putg(ss_packet, es_packet, ANN_RGB, [text]) | |
84 | self.bits.clear() | |
85 | ||
86 | def handle_bit(self, ss, es, value, ann_late = False): | |
87 | if not ann_late: | |
88 | text = ['{:d}'.format(value)] | |
89 | self.putg(ss, es, ANN_BIT, text) | |
90 | item = (value, ss, es) | |
91 | self.bits.append(item) | |
92 | self.handle_bits() | |
93 | if ann_late: | |
94 | text = ['{:d}'.format(value)] | |
95 | self.putg(ss, es, ANN_BIT, text) | |
66fc6e7c | 96 | |
7a85bbbe | 97 | def decode(self): |
66fc6e7c UH |
98 | if not self.samplerate: |
99 | raise SamplerateError('Cannot decode without samplerate.') | |
6d1cde1d | 100 | self.need_bits = len(self.options['type']) * 8 |
66fc6e7c | 101 | |
5e8090d7 GS |
102 | # Either check for edges which communicate bit values, or for |
103 | # long periods of idle level which represent a reset pulse. | |
104 | # Track the left-most, right-most, and inner edge positions of | |
105 | # a bit. The positive period's width determines the bit's value. | |
106 | # Initially synchronize to the input stream by searching for a | |
107 | # low period, which preceeds a data bit or starts a reset pulse. | |
108 | # Don't annotate the very first reset pulse, but process it. We | |
109 | # may not see the right-most edge of a data bit when reset is | |
110 | # adjacent to that bit time. | |
111 | cond_bit_starts = {0: 'r'} | |
112 | cond_inbit_edge = {0: 'f'} | |
113 | samples_625ns = int(self.samplerate * 625e-9) | |
114 | samples_50us = round(self.samplerate * 50e-6) | |
115 | cond_reset_pulse = {'skip': samples_50us + 1} | |
116 | conds = [cond_bit_starts, cond_inbit_edge, cond_reset_pulse] | |
117 | ss_bit, inv_bit, es_bit = None, None, None | |
118 | pin, = self.wait({0: 'l'}) | |
119 | inv_bit = self.samplenum | |
120 | check_reset = False | |
7a85bbbe | 121 | while True: |
5e8090d7 GS |
122 | pin, = self.wait(conds) |
123 | ||
124 | # Check RESET condition. Manufacturers may disagree on the | |
125 | # minimal pulse width. 50us are recommended in datasheets, | |
126 | # experiments suggest the limit is around 10us. | |
127 | # When the RESET pulse is adjacent to the low phase of the | |
128 | # last bit time, we have no appropriate condition for the | |
129 | # bit time's end location. That's why this BIT's annotation | |
130 | # is shorter (only spans the high phase), and the RESET | |
131 | # annotation immediately follows (spans from the falling edge | |
132 | # to the end of the minimum RESET pulse width). | |
133 | if check_reset and self.matched[2]: | |
134 | es_bit = inv_bit | |
135 | ss_rst, es_rst = inv_bit, self.samplenum | |
136 | ||
137 | if ss_bit and inv_bit and es_bit: | |
138 | # Decode last bit value. Use the last processed bit's | |
139 | # width for comparison when available. Fallback to an | |
140 | # arbitrary threshold otherwise (which can result in | |
141 | # false detection of value 1 for those captures where | |
142 | # high and low pulses are of similar width). | |
143 | duty = inv_bit - ss_bit | |
144 | thres = samples_625ns | |
145 | if self.bits: | |
146 | period = self.bits[-1][2] - self.bits[-1][1] | |
147 | thres = period * 0.5 | |
148 | bit_value = 1 if duty >= thres else 0 | |
149 | self.handle_bit(ss_bit, inv_bit, bit_value, True) | |
150 | ||
151 | if ss_rst and es_rst: | |
152 | text = ['RESET', 'RST', 'R'] | |
153 | self.putg(ss_rst, es_rst, ANN_RESET, text) | |
154 | check_reset = False | |
7a85bbbe | 155 | |
6d1cde1d | 156 | self.bits.clear() |
5e8090d7 GS |
157 | ss_bit, inv_bit, es_bit = None, None, None |
158 | ||
159 | # Rising edge starts a bit time. Falling edge ends its high | |
160 | # period. Get the previous bit's duty cycle and thus its | |
161 | # bit value when the next bit starts. | |
162 | if self.matched[0]: # and pin: | |
163 | check_reset = False | |
164 | if ss_bit and inv_bit: | |
165 | # Got a previous bit? Handle it. | |
166 | es_bit = self.samplenum | |
167 | period = es_bit - ss_bit | |
168 | duty = inv_bit - ss_bit | |
66fc6e7c | 169 | # Ideal duty for T0H: 33%, T1H: 66%. |
5e8090d7 GS |
170 | bit_value = 1 if (duty / period) > 0.5 else 0 |
171 | self.handle_bit(ss_bit, es_bit, bit_value) | |
172 | ss_bit, inv_bit, es_bit = self.samplenum, None, None | |
173 | if self.matched[1]: # and not pin: | |
174 | check_reset = True | |
175 | inv_bit = self.samplenum |