1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2017 Christoph Rackwitz <christoph.rackwitz@rwth-aachen.de>
##
## 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 2 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, see <http://www.gnu.org/licenses/>.
##
import math
import sigrokdecode as srd
from collections import deque
from common.srdhelper import bitpack, bitunpack
def gray_encode(plain):
return plain & (plain >> 1)
def gray_decode(gray):
temp = gray
temp ^= (temp >> 8)
temp ^= (temp >> 4)
temp ^= (temp >> 2)
temp ^= (temp >> 1)
return temp
def prefix_fmt(value, emin=None):
sgn = (value > 0) - (value < 0)
value = abs(value)
p = math.log10(value) if value else 0
value = sgn * math.floor(value * 10**int(3 - p)) * 10**-int(3 - p)
e = p // 3 * 3
if emin is not None and e < emin:
e = emin
value *= 10**-e
p -= e
decimals = 2 - int(p)
prefixes = {-9: 'n', -6: 'µ', -3: 'm', 0: '', 3: 'k', 6: 'M', 9: 'G'}
return '{0:.{1}f} {2}'.format(value, decimals, prefixes[e])
class ChannelMapError(Exception):
pass
class Value:
def __init__(self, onchange):
self.onchange = onchange
self.timestamp = None
self.value = None
def get(self):
return self.value
def set(self, timestamp, newval):
if newval != self.value:
if self.value is not None:
self.onchange(self.timestamp, self.value, timestamp, newval)
self.value = newval
self.timestamp = timestamp
elif False:
if self.value is not None:
self.onchange(self.timestamp, self.value, timestamp, newval)
MAX_CHANNELS = 8 # 10 channels causes some weird problems...
class Decoder(srd.Decoder):
api_version = 3
id = 'graycode'
name = 'Gray code'
longname = 'Gray code and rotary encoder'
desc = 'Accumulate rotary encoder increments, provide timing statistics.'
license = 'gplv2+'
inputs = ['logic']
outputs = ['graycode']
optional_channels = tuple(
{'id': 'd{}'.format(i), 'name': 'D{}'.format(i), 'desc': 'Data line {}'.format(i)}
for i in range(MAX_CHANNELS)
)
options = (
{'id': 'edges', 'desc': 'Edges per rotation', 'default': 0},
{'id': 'avg_period', 'desc': 'Averaging period', 'default': 10},
)
annotations = (
('phase', 'Phase'),
('increment', 'Increment'),
('count', 'Count'),
('turns', 'Turns'),
('interval', 'Interval'),
('average', 'Average'),
('rpm', 'Rate'),
)
annotation_rows = tuple((u, v, (i,)) for i, (u, v) in enumerate(annotations))
def __init__(self):
self.num_channels = 0
self.samplerate = None
self.last_n = deque()
self.phase = Value(self.on_phase)
self.increment = Value(self.on_increment)
self.count = Value(self.on_count)
self.turns = Value(self.on_turns)
def on_phase(self, told, vold, tnew, vnew):
self.put(told, tnew, self.out_ann, [0, ['{}'.format(vold)]])
def on_increment(self, told, vold, tnew, vnew):
if vold == 0:
message = '0'
elif abs(vold) == self.ENCODER_STEPS // 2:
message = '±π'
else:
message = '{:+d}'.format(vold)
self.put(told, tnew, self.out_ann, [1, [message]])
def on_count(self, told, vold, tnew, vnew):
self.put(told, tnew, self.out_ann, [2, ['{}'.format(vold)]])
def on_turns(self, told, vold, tnew, vnew):
self.put(told, tnew, self.out_ann, [3, ['{:+d}'.format(vold)]])
def metadata(self, key, value):
if key == srd.SRD_CONF_SAMPLERATE:
self.samplerate = value
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
def decode(self):
chmask = [self.has_channel(i) for i in range(MAX_CHANNELS)]
self.num_channels = sum(chmask)
if chmask != [i < self.num_channels for i in range(MAX_CHANNELS)]:
raise ChannelMapError('Assigned channels need to be contiguous')
self.ENCODER_STEPS = 1 << self.num_channels
startbits = self.wait()
curtime = self.samplenum
self.turns.set(self.samplenum, 0)
self.count.set(self.samplenum, 0)
self.phase.set(self.samplenum, gray_decode(bitpack(startbits[:self.num_channels])))
while True:
prevtime = curtime
bits = self.wait([{i: 'e'} for i in range(self.num_channels)])
curtime = self.samplenum
oldcount = self.count.get()
oldphase = self.phase.get()
newphase = gray_decode(bitpack(bits[:self.num_channels]))
self.phase.set(self.samplenum, newphase)
phasedelta_raw = (newphase - oldphase + (self.ENCODER_STEPS // 2 - 1)) % self.ENCODER_STEPS - (self.ENCODER_STEPS // 2 - 1)
phasedelta = phasedelta_raw
self.increment.set(self.samplenum, phasedelta)
if abs(phasedelta) == self.ENCODER_STEPS // 2:
phasedelta = 0
self.count.set(self.samplenum, self.count.get() + phasedelta)
if self.options['edges']:
self.turns.set(self.samplenum, self.count.get() // self.options['edges'])
if self.samplerate is not None:
period = (curtime - prevtime) / self.samplerate
freq = abs(phasedelta_raw) / period
self.put(prevtime, curtime, self.out_ann, [4, [
'{}s, {}Hz'.format(prefix_fmt(period), prefix_fmt(freq))]])
if self.options['avg_period']:
self.last_n.append((abs(phasedelta_raw), period))
if len(self.last_n) > self.options['avg_period']:
self.last_n.popleft()
avg_period = sum(v for u, v in self.last_n) / (sum(u for u, v in self.last_n) or 1)
self.put(prevtime, curtime, self.out_ann, [5, [
'{}s, {}Hz'.format(prefix_fmt(avg_period),
prefix_fmt(1 / avg_period))]])
if self.options['edges']:
self.put(prevtime, curtime, self.out_ann, [6, ['{}rpm'.format(prefix_fmt(60 * freq / self.options['edges'], emin=0))]])
|
