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authorUwe Hermann <uwe@hermann-uwe.de>2016-02-15 00:06:38 +0300
committerUwe Hermann <uwe@hermann-uwe.de>2016-03-04 00:35:47 +0100
commit66fc6e7c21878ae7e7ee65096fdf304133de3136 (patch)
tree08f25152fbffc4798effd9b91382c7e6b96248e4
parente2bc7a1e2f4e40250d117c587ad02343257d0f2a (diff)
downloadlibsigrokdecode-66fc6e7c21878ae7e7ee65096fdf304133de3136.tar.gz
libsigrokdecode-66fc6e7c21878ae7e7ee65096fdf304133de3136.zip
Add an rgb_led_ws281x decoder.
This decoder handles the WS2812B protocol (and possibly WS2811). Example dump already exists: led/ws281x/ws281x_4ch_5mhz.sr. Signed-off-by: Vladimir Ermakov <vooon341@gmail.com>
-rw-r--r--decoders/rgb_led_ws281x/__init__.py28
-rw-r--r--decoders/rgb_led_ws281x/pd.py128
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