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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 | from common.srdhelper import bitpack, bitunpack | |
24 | ||
25 | def gray_encode(plain): | |
26 | return plain & (plain >> 1) | |
27 | ||
28 | def gray_decode(gray): | |
29 | temp = gray | |
30 | temp ^= (temp >> 8) | |
31 | temp ^= (temp >> 4) | |
32 | temp ^= (temp >> 2) | |
33 | temp ^= (temp >> 1) | |
34 | return temp | |
35 | ||
36 | def prefix_fmt(value, emin=None): | |
37 | sgn = (value > 0) - (value < 0) | |
38 | value = abs(value) | |
39 | p = math.log10(value) if value else 0 | |
40 | value = sgn * math.floor(value * 10**int(3 - p)) * 10**-int(3 - p) | |
41 | e = p // 3 * 3 | |
42 | if emin is not None and e < emin: | |
43 | e = emin | |
44 | value *= 10**-e | |
45 | p -= e | |
46 | decimals = 2 - int(p) | |
47 | prefixes = {-9: 'n', -6: 'µ', -3: 'm', 0: '', 3: 'k', 6: 'M', 9: 'G'} | |
48 | return '{0:.{1}f} {2}'.format(value, decimals, prefixes[e]) | |
49 | ||
50 | class ChannelMapError(Exception): | |
51 | pass | |
52 | ||
53 | class Value: | |
54 | def __init__(self, onchange): | |
55 | self.onchange = onchange | |
56 | self.timestamp = None | |
57 | self.value = None | |
58 | ||
59 | def get(self): | |
60 | return self.value | |
61 | ||
62 | def set(self, timestamp, newval): | |
63 | if newval != self.value: | |
64 | if self.value is not None: | |
65 | self.onchange(self.timestamp, self.value, timestamp, newval) | |
66 | ||
67 | self.value = newval | |
68 | self.timestamp = timestamp | |
69 | elif False: | |
70 | if self.value is not None: | |
71 | self.onchange(self.timestamp, self.value, timestamp, newval) | |
72 | ||
73 | MAX_CHANNELS = 8 # 10 channels causes some weird problems... | |
74 | ||
75 | class Decoder(srd.Decoder): | |
76 | api_version = 3 | |
77 | id = 'graycode' | |
78 | name = 'Gray code' | |
79 | longname = 'Gray code and rotary encoder' | |
80 | desc = 'Accumulate rotary encoder increments, provide timing statistics.' | |
81 | license = 'gplv2+' | |
82 | inputs = ['logic'] | |
83 | outputs = ['graycode'] | |
84 | optional_channels = tuple( | |
85 | {'id': 'd{}'.format(i), 'name': 'D{}'.format(i), 'desc': 'Data line {}'.format(i)} | |
86 | for i in range(MAX_CHANNELS) | |
87 | ) | |
88 | options = ( | |
89 | {'id': 'edges', 'desc': 'Edges per rotation', 'default': 0}, | |
90 | {'id': 'avg_period', 'desc': 'Averaging period', 'default': 10}, | |
91 | ) | |
92 | annotations = ( | |
93 | ('phase', 'Phase'), | |
94 | ('increment', 'Increment'), | |
95 | ('count', 'Count'), | |
96 | ('turns', 'Turns'), | |
97 | ('interval', 'Interval'), | |
98 | ('average', 'Average'), | |
99 | ('rpm', 'Rate'), | |
100 | ) | |
101 | annotation_rows = tuple((u, v, (i,)) for i, (u, v) in enumerate(annotations)) | |
102 | ||
103 | def __init__(self): | |
104 | self.reset() | |
105 | ||
106 | def reset(self): | |
107 | self.num_channels = 0 | |
108 | self.samplerate = None | |
109 | self.last_n = deque() | |
110 | ||
111 | self.phase = Value(self.on_phase) | |
112 | self.increment = Value(self.on_increment) | |
113 | self.count = Value(self.on_count) | |
114 | self.turns = Value(self.on_turns) | |
115 | ||
116 | def on_phase(self, told, vold, tnew, vnew): | |
117 | self.put(told, tnew, self.out_ann, [0, ['{}'.format(vold)]]) | |
118 | ||
119 | def on_increment(self, told, vold, tnew, vnew): | |
120 | if vold == 0: | |
121 | message = '0' | |
122 | elif abs(vold) == self.ENCODER_STEPS // 2: | |
123 | message = '±π' | |
124 | else: | |
125 | message = '{:+d}'.format(vold) | |
126 | self.put(told, tnew, self.out_ann, [1, [message]]) | |
127 | ||
128 | def on_count(self, told, vold, tnew, vnew): | |
129 | self.put(told, tnew, self.out_ann, [2, ['{}'.format(vold)]]) | |
130 | ||
131 | def on_turns(self, told, vold, tnew, vnew): | |
132 | self.put(told, tnew, self.out_ann, [3, ['{:+d}'.format(vold)]]) | |
133 | ||
134 | def metadata(self, key, value): | |
135 | if key == srd.SRD_CONF_SAMPLERATE: | |
136 | self.samplerate = value | |
137 | ||
138 | def start(self): | |
139 | self.out_ann = self.register(srd.OUTPUT_ANN) | |
140 | ||
141 | def decode(self): | |
142 | chmask = [self.has_channel(i) for i in range(MAX_CHANNELS)] | |
143 | self.num_channels = sum(chmask) | |
144 | if chmask != [i < self.num_channels for i in range(MAX_CHANNELS)]: | |
145 | raise ChannelMapError('Assigned channels need to be contiguous') | |
146 | ||
147 | self.ENCODER_STEPS = 1 << self.num_channels | |
148 | ||
149 | startbits = self.wait() | |
150 | curtime = self.samplenum | |
151 | ||
152 | self.turns.set(self.samplenum, 0) | |
153 | self.count.set(self.samplenum, 0) | |
154 | self.phase.set(self.samplenum, gray_decode(bitpack(startbits[:self.num_channels]))) | |
155 | ||
156 | while True: | |
157 | prevtime = curtime | |
158 | bits = self.wait([{i: 'e'} for i in range(self.num_channels)]) | |
159 | curtime = self.samplenum | |
160 | ||
161 | oldcount = self.count.get() | |
162 | oldphase = self.phase.get() | |
163 | ||
164 | newphase = gray_decode(bitpack(bits[:self.num_channels])) | |
165 | self.phase.set(self.samplenum, newphase) | |
166 | ||
167 | phasedelta_raw = (newphase - oldphase + (self.ENCODER_STEPS // 2 - 1)) % self.ENCODER_STEPS - (self.ENCODER_STEPS // 2 - 1) | |
168 | phasedelta = phasedelta_raw | |
169 | self.increment.set(self.samplenum, phasedelta) | |
170 | if abs(phasedelta) == self.ENCODER_STEPS // 2: | |
171 | phasedelta = 0 | |
172 | ||
173 | self.count.set(self.samplenum, self.count.get() + phasedelta) | |
174 | ||
175 | if self.options['edges']: | |
176 | self.turns.set(self.samplenum, self.count.get() // self.options['edges']) | |
177 | ||
178 | if self.samplerate is not None: | |
179 | period = (curtime - prevtime) / self.samplerate | |
180 | freq = abs(phasedelta_raw) / period | |
181 | ||
182 | self.put(prevtime, curtime, self.out_ann, [4, [ | |
183 | '{}s, {}Hz'.format(prefix_fmt(period), prefix_fmt(freq))]]) | |
184 | ||
185 | if self.options['avg_period']: | |
186 | self.last_n.append((abs(phasedelta_raw), period)) | |
187 | if len(self.last_n) > self.options['avg_period']: | |
188 | self.last_n.popleft() | |
189 | ||
190 | avg_period = sum(v for u, v in self.last_n) / (sum(u for u, v in self.last_n) or 1) | |
191 | self.put(prevtime, curtime, self.out_ann, [5, [ | |
192 | '{}s, {}Hz'.format(prefix_fmt(avg_period), | |
193 | prefix_fmt(1 / avg_period))]]) | |
194 | ||
195 | if self.options['edges']: | |
196 | self.put(prevtime, curtime, self.out_ann, [6, ['{}rpm'.format(prefix_fmt(60 * freq / self.options['edges'], emin=0))]]) |