2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2016 Vladimir Ermakov <vooon341@gmail.com>
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.
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.
16 ## You should have received a copy of the GNU General Public License
17 ## along with this program; if not, write to the Free Software
18 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 import sigrokdecode as srd
22 from functools import reduce
24 class SamplerateError(Exception):
27 class Decoder(srd.Decoder):
30 name = 'RGB LED (WS281x)'
31 longname = 'RGB LED string decoder (WS281x)'
32 desc = 'RGB LED string protocol (WS281x).'
35 outputs = ['rgb_led_ws281x']
37 {'id': 'din', 'name': 'DIN', 'desc': 'DIN data line'},
45 ('bit', 'Bits', (0, 1)),
50 self.samplerate = None
59 self.out_ann = self.register(srd.OUTPUT_ANN)
61 def metadata(self, key, value):
62 if key == srd.SRD_CONF_SAMPLERATE:
63 self.samplerate = value
65 def handle_bits(self, samplenum):
66 if len(self.bits) == 24:
67 grb = reduce(lambda a, b: (a << 1) | b, self.bits)
68 rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0x0000ff)
69 self.put(self.ss_packet, samplenum, self.out_ann,
74 def decode(self, ss, es, data):
75 if not self.samplerate:
76 raise SamplerateError('Cannot decode without samplerate.')
78 for (samplenum, (pin, )) in data:
79 if self.oldpin is None:
83 # Check RESET condition (manufacturer recommends 50 usec minimal,
84 # but real minimum is ~10 usec).
85 if not self.inreset and not pin and self.es is not None and \
86 (samplenum - self.es) / self.samplerate > 50e-6:
88 # Decode last bit value.
89 tH = (self.es - self.ss) / self.samplerate
90 bit_ = True if tH >= 625e-9 else False
92 self.bits.append(bit_)
93 self.handle_bits(self.es)
95 self.put(self.ss, self.es, self.out_ann, [0, ['%d' % bit_]])
96 self.put(self.es, samplenum, self.out_ann,
97 [1, ['RESET', 'RST', 'R']])
101 self.ss_packet = None
104 if not self.oldpin and pin:
106 if self.ss and self.es:
107 period = samplenum - self.ss
108 duty = self.es - self.ss
109 # Ideal duty for T0H: 33%, T1H: 66%.
110 bit_ = (duty / period) > 0.5
112 self.put(self.ss, samplenum, self.out_ann,
115 self.bits.append(bit_)
116 self.handle_bits(samplenum)
118 if self.ss_packet is None:
119 self.ss_packet = samplenum
123 elif self.oldpin and not pin: