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1 | ## |
2 | ## This file is part of the libsigrokdecode project. | |
3 | ## | |
4 | ## Copyright (C) 2017 Christoph Rackwitz <christoph.rackwitz@rwth-aachen.de> | |
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 2 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 | |
17 | ## along with this program; if not, see <http://www.gnu.org/licenses/>. | |
18 | ## | |
19 | ||
20 | import math | |
21 | import sigrokdecode as srd | |
22 | from collections import deque | |
23 | ||
24 | def bitpack(bits): | |
25 | res = 0 | |
26 | for i, b in enumerate(bits): | |
27 | res |= b << i | |
28 | return res | |
29 | ||
30 | def bitunpack(num, minbits=0): | |
31 | res = [] | |
32 | while num or minbits > 0: | |
33 | res.append(num & 1) | |
34 | num >>= 1 | |
35 | minbits -= 1 | |
36 | return tuple(res) | |
37 | ||
38 | def gray_encode(plain): | |
39 | return plain & (plain >> 1) | |
40 | ||
41 | def gray_decode(gray): | |
42 | temp = gray | |
43 | temp ^= (temp >> 8) | |
44 | temp ^= (temp >> 4) | |
45 | temp ^= (temp >> 2) | |
46 | temp ^= (temp >> 1) | |
47 | return temp | |
48 | ||
49 | def prefix_fmt(value, emin=None): | |
50 | sgn = (value > 0) - (value < 0) | |
51 | value = abs(value) | |
52 | p = math.log10(value) if value else 0 | |
53 | value = sgn * math.floor(value * 10**int(3 - p)) * 10**-int(3 - p) | |
54 | e = p // 3 * 3 | |
55 | if emin is not None and e < emin: | |
56 | e = emin | |
57 | value *= 10**-e | |
58 | p -= e | |
59 | decimals = 2 - int(p) | |
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]) | |
62 | ||
63 | class ChannelMapError(Exception): | |
64 | pass | |
65 | ||
66 | class Value: | |
67 | def __init__(self, onchange): | |
68 | self.onchange = onchange | |
69 | self.timestamp = None | |
70 | self.value = None | |
71 | ||
72 | def get(self): | |
73 | return self.value | |
74 | ||
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) | |
79 | ||
80 | self.value = newval | |
81 | self.timestamp = timestamp | |
82 | elif False: | |
83 | if self.value is not None: | |
84 | self.onchange(self.timestamp, self.value, timestamp, newval) | |
85 | ||
86 | MAX_CHANNELS = 8 # 10 channels causes some weird problems... | |
87 | ||
88 | class Decoder(srd.Decoder): | |
89 | api_version = 3 | |
90 | id = 'graycode' | |
91 | name = 'Gray code' | |
92 | longname = 'Gray code and rotary encoder' | |
93 | desc = 'Accumulate rotary encoder increments, provide timing statistics.' | |
94 | license = 'gplv2+' | |
95 | inputs = ['logic'] | |
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) | |
100 | ) | |
101 | options = ( | |
102 | {'id': 'edges', 'desc': 'Edges per rotation', 'default': 0}, | |
103 | {'id': 'avg_period', 'desc': 'Averaging period', 'default': 10}, | |
104 | ) | |
105 | annotations = ( | |
106 | ('phase', 'Phase'), | |
107 | ('increment', 'Increment'), | |
108 | ('count', 'Count'), | |
109 | ('turns', 'Turns'), | |
110 | ('interval', 'Interval'), | |
111 | ('average', 'Average'), | |
112 | ('rpm', 'Rate'), | |
113 | ) | |
114 | annotation_rows = tuple((u, v, (i,)) for i, (u, v) in enumerate(annotations)) | |
115 | ||
116 | def __init__(self): | |
117 | self.num_channels = 0 | |
118 | self.samplerate = None | |
119 | self.last_n = deque() | |
120 | ||
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) | |
125 | ||
126 | def on_phase(self, told, vold, tnew, vnew): | |
127 | self.put(told, tnew, self.out_ann, [0, ['{}'.format(vold)]]) | |
128 | ||
129 | def on_increment(self, told, vold, tnew, vnew): | |
130 | if vold == 0: | |
131 | message = '0' | |
132 | elif abs(vold) == self.ENCODER_STEPS // 2: | |
133 | message = '±π' | |
134 | else: | |
135 | message = '{:+d}'.format(vold) | |
136 | self.put(told, tnew, self.out_ann, [1, [message]]) | |
137 | ||
138 | def on_count(self, told, vold, tnew, vnew): | |
139 | self.put(told, tnew, self.out_ann, [2, ['{}'.format(vold)]]) | |
140 | ||
141 | def on_turns(self, told, vold, tnew, vnew): | |
142 | self.put(told, tnew, self.out_ann, [3, ['{:+d}'.format(vold)]]) | |
143 | ||
144 | def metadata(self, key, value): | |
145 | if key == srd.SRD_CONF_SAMPLERATE: | |
146 | self.samplerate = value | |
147 | ||
148 | def start(self): | |
149 | self.out_ann = self.register(srd.OUTPUT_ANN) | |
150 | ||
151 | def decode(self): | |
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') | |
156 | ||
157 | self.ENCODER_STEPS = 1 << self.num_channels | |
158 | ||
159 | startbits = self.wait() | |
160 | curtime = self.samplenum | |
161 | ||
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]))) | |
165 | ||
166 | while True: | |
167 | prevtime = curtime | |
168 | bits = self.wait([{i: 'e'} for i in range(self.num_channels)]) | |
169 | curtime = self.samplenum | |
170 | ||
171 | oldcount = self.count.get() | |
172 | oldphase = self.phase.get() | |
173 | ||
174 | newphase = gray_decode(bitpack(bits[:self.num_channels])) | |
175 | self.phase.set(self.samplenum, newphase) | |
176 | ||
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: | |
181 | phasedelta = 0 | |
182 | ||
183 | self.count.set(self.samplenum, self.count.get() + phasedelta) | |
184 | ||
185 | if self.options['edges']: | |
186 | self.turns.set(self.samplenum, self.count.get() // self.options['edges']) | |
187 | ||
188 | if self.samplerate is not None: | |
189 | period = (curtime - prevtime) / self.samplerate | |
190 | freq = abs(phasedelta_raw) / period | |
191 | ||
192 | self.put(prevtime, curtime, self.out_ann, [4, [ | |
193 | '{}s, {}Hz'.format(prefix_fmt(period), prefix_fmt(freq))]]) | |
194 | ||
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() | |
199 | ||
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))]]) | |
204 | ||
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))]]) |