2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2017 Christoph Rackwitz <christoph.rackwitz@rwth-aachen.de>
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 2 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, see <http://www.gnu.org/licenses/>.
21 import sigrokdecode as srd
22 from collections import deque
26 for i, b in enumerate(bits):
30 def bitunpack(num, minbits=0):
32 while num or minbits > 0:
38 def gray_encode(plain):
39 return plain & (plain >> 1)
41 def gray_decode(gray):
49 def prefix_fmt(value, emin=None):
50 sgn = (value > 0) - (value < 0)
52 p = math.log10(value) if value else 0
53 value = sgn * math.floor(value * 10**int(3 - p)) * 10**-int(3 - p)
55 if emin is not None and e < emin:
60 prefixes = {-9: 'n', -6: 'µ', -3: 'm', 0: '', 3: 'k', 6: 'M', 9: 'G'}
61 return '{0:.{1}f} {2}'.format(value, decimals, prefixes[e])
63 class ChannelMapError(Exception):
67 def __init__(self, onchange):
68 self.onchange = onchange
75 def set(self, timestamp, newval):
76 if newval != self.value:
77 if self.value is not None:
78 self.onchange(self.timestamp, self.value, timestamp, newval)
81 self.timestamp = timestamp
83 if self.value is not None:
84 self.onchange(self.timestamp, self.value, timestamp, newval)
86 MAX_CHANNELS = 8 # 10 channels causes some weird problems...
88 class Decoder(srd.Decoder):
92 longname = 'Gray code and rotary encoder'
93 desc = 'Accumulate rotary encoder increments, provide timing statistics.'
96 outputs = ['graycode']
97 optional_channels = tuple(
98 {'id': 'd{}'.format(i), 'name': 'D{}'.format(i), 'desc': 'Data line {}'.format(i)}
99 for i in range(MAX_CHANNELS)
102 {'id': 'edges', 'desc': 'Edges per rotation', 'default': 0},
103 {'id': 'avg_period', 'desc': 'Averaging period', 'default': 10},
107 ('increment', 'Increment'),
110 ('interval', 'Interval'),
111 ('average', 'Average'),
114 annotation_rows = tuple((u, v, (i,)) for i, (u, v) in enumerate(annotations))
117 self.num_channels = 0
118 self.samplerate = None
119 self.last_n = deque()
121 self.phase = Value(self.on_phase)
122 self.increment = Value(self.on_increment)
123 self.count = Value(self.on_count)
124 self.turns = Value(self.on_turns)
126 def on_phase(self, told, vold, tnew, vnew):
127 self.put(told, tnew, self.out_ann, [0, ['{}'.format(vold)]])
129 def on_increment(self, told, vold, tnew, vnew):
132 elif abs(vold) == self.ENCODER_STEPS // 2:
135 message = '{:+d}'.format(vold)
136 self.put(told, tnew, self.out_ann, [1, [message]])
138 def on_count(self, told, vold, tnew, vnew):
139 self.put(told, tnew, self.out_ann, [2, ['{}'.format(vold)]])
141 def on_turns(self, told, vold, tnew, vnew):
142 self.put(told, tnew, self.out_ann, [3, ['{:+d}'.format(vold)]])
144 def metadata(self, key, value):
145 if key == srd.SRD_CONF_SAMPLERATE:
146 self.samplerate = value
149 self.out_ann = self.register(srd.OUTPUT_ANN)
152 chmask = [self.has_channel(i) for i in range(MAX_CHANNELS)]
153 self.num_channels = sum(chmask)
154 if chmask != [i < self.num_channels for i in range(MAX_CHANNELS)]:
155 raise ChannelMapError('Assigned channels need to be contiguous')
157 self.ENCODER_STEPS = 1 << self.num_channels
159 startbits = self.wait()
160 curtime = self.samplenum
162 self.turns.set(self.samplenum, 0)
163 self.count.set(self.samplenum, 0)
164 self.phase.set(self.samplenum, gray_decode(bitpack(startbits[:self.num_channels])))
168 bits = self.wait([{i: 'e'} for i in range(self.num_channels)])
169 curtime = self.samplenum
171 oldcount = self.count.get()
172 oldphase = self.phase.get()
174 newphase = gray_decode(bitpack(bits[:self.num_channels]))
175 self.phase.set(self.samplenum, newphase)
177 phasedelta_raw = (newphase - oldphase + (self.ENCODER_STEPS // 2 - 1)) % self.ENCODER_STEPS - (self.ENCODER_STEPS // 2 - 1)
178 phasedelta = phasedelta_raw
179 self.increment.set(self.samplenum, phasedelta)
180 if abs(phasedelta) == self.ENCODER_STEPS // 2:
183 self.count.set(self.samplenum, self.count.get() + phasedelta)
185 if self.options['edges']:
186 self.turns.set(self.samplenum, self.count.get() // self.options['edges'])
188 if self.samplerate is not None:
189 period = (curtime - prevtime) / self.samplerate
190 freq = abs(phasedelta_raw) / period
192 self.put(prevtime, curtime, self.out_ann, [4, [
193 '{}s, {}Hz'.format(prefix_fmt(period), prefix_fmt(freq))]])
195 if self.options['avg_period']:
196 self.last_n.append((abs(phasedelta_raw), period))
197 if len(self.last_n) > self.options['avg_period']:
198 self.last_n.popleft()
200 avg_period = sum(v for u, v in self.last_n) / (sum(u for u, v in self.last_n) or 1)
201 self.put(prevtime, curtime, self.out_ann, [5, [
202 '{}s, {}Hz'.format(prefix_fmt(avg_period),
203 prefix_fmt(1 / avg_period))]])
205 if self.options['edges']:
206 self.put(prevtime, curtime, self.out_ann, [6, ['{}rpm'.format(prefix_fmt(60 * freq / self.options['edges'], emin=0))]])