diff options
Diffstat (limited to 'decoders/rgb_led_ws281x')
| -rw-r--r-- | decoders/rgb_led_ws281x/__init__.py | 28 | ||||
| -rw-r--r-- | decoders/rgb_led_ws281x/pd.py | 128 |
2 files changed, 156 insertions, 0 deletions
diff --git a/decoders/rgb_led_ws281x/__init__.py b/decoders/rgb_led_ws281x/__init__.py new file mode 100644 index 0000000..63135a4 --- /dev/null +++ b/decoders/rgb_led_ws281x/__init__.py @@ -0,0 +1,28 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2016 Vladimir Ermakov <vooon341@gmail.com> +## +## This program is free software; you can redistribute it and/or modify +## it under the terms of the GNU General Public License as published by +## the Free Software Foundation; either version 3 of the License, or +## (at your option) any later version. +## +## This program is distributed in the hope that it will be useful, +## but WITHOUT ANY WARRANTY; without even the implied warranty of +## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +## GNU General Public License for more details. +## +## You should have received a copy of the GNU General Public License +## along with this program; if not, write to the Free Software +## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +## + +''' +WS281x RGB LED protocol decoder. + +Details: +https://cpldcpu.wordpress.com/2014/01/14/light_ws2812-library-v2-0-part-i-understanding-the-ws2812/ +''' + +from .pd import Decoder diff --git a/decoders/rgb_led_ws281x/pd.py b/decoders/rgb_led_ws281x/pd.py new file mode 100644 index 0000000..e317b71 --- /dev/null +++ b/decoders/rgb_led_ws281x/pd.py @@ -0,0 +1,128 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2016 Vladimir Ermakov <vooon341@gmail.com> +## +## This program is free software; you can redistribute it and/or modify +## it under the terms of the GNU General Public License as published by +## the Free Software Foundation; either version 3 of the License, or +## (at your option) any later version. +## +## This program is distributed in the hope that it will be useful, +## but WITHOUT ANY WARRANTY; without even the implied warranty of +## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +## GNU General Public License for more details. +## +## You should have received a copy of the GNU General Public License +## along with this program; if not, write to the Free Software +## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +## + +import sigrokdecode as srd +from functools import reduce + +class SamplerateError(Exception): + pass + +class Decoder(srd.Decoder): + api_version = 2 + id = 'rgb_led_ws281x' + name = 'RGB LED (WS281x)' + longname = 'RGB LED string decoder (WS281x)' + desc = 'RGB LED string protocol (WS281x).' + license = 'gplv3+' + inputs = ['logic'] + outputs = ['rgb_led_ws281x'] + channels = ( + {'id': 'din', 'name': 'DIN', 'desc': 'DIN data line'}, + ) + annotations = ( + ('bit', 'Bit'), + ('reset', 'RESET'), + ('rgb', 'RGB'), + ) + annotation_rows = ( + ('bit', 'Bits', (0, 1)), + ('rgb', 'RGB', (2,)), + ) + + def __init__(self, **kwargs): + self.samplerate = None + self.oldpin = None + self.packet_ss = None + self.ss = None + self.es = None + self.bits = [] + self.inreset = False + + def start(self): + self.out_ann = self.register(srd.OUTPUT_ANN) + + def metadata(self, key, value): + if key == srd.SRD_CONF_SAMPLERATE: + self.samplerate = value + + def handle_bits(self, samplenum): + if len(self.bits) == 24: + grb = reduce(lambda a, b: (a << 1) | b, self.bits) + rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0x0000ff) + self.put(self.packet_ss, samplenum, self.out_ann, + [2, ['#%06x' % rgb]]) + self.bits = [] + self.packet_ss = None + + def decode(self, ss, es, data): + if not self.samplerate: + raise SamplerateError('Cannot decode without samplerate.') + + for (samplenum, (pin, )) in data: + if self.oldpin is None: + self.oldpin = pin + continue + + # Check RESET condition (manufacturer recommends 50 usec minimal, + # but real minimum is ~10 usec). + if not self.inreset and not pin and self.es is not None and \ + (samplenum - self.es) / self.samplerate > 50e-6: + + # Decode last bit value. + tH = (self.es - self.ss) / self.samplerate + bit_ = True if tH >= 625e-9 else False + + self.bits.append(bit_) + self.handle_bits(self.es) + + self.put(self.ss, self.es, self.out_ann, [0, ['%d' % bit_]]) + self.put(self.es, samplenum, self.out_ann, + [1, ['RESET', 'RST', 'R']]) + + self.inreset = True + self.bits = [] + self.packet_ss = None + self.ss = None + + if not self.oldpin and pin: + # Rising edge. + if self.ss and self.es: + period = samplenum - self.ss + duty = self.es - self.ss + # Ideal duty for T0H: 33%, T1H: 66%. + bit_ = (duty / period) > 0.5 + + self.put(self.ss, samplenum, self.out_ann, + [0, ['%d' % bit_]]) + + self.bits.append(bit_) + self.handle_bits(samplenum) + + if self.packet_ss is None: + self.packet_ss = samplenum + + self.ss = samplenum + + elif self.oldpin and not pin: + # Falling edge. + self.inreset = False + self.es = samplenum + + self.oldpin = pin |