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1 | ## | |
2 | ## This file is part of the libsigrokdecode project. | |
3 | ## | |
4 | ## Copyright (C) 2014 Torsten Duwe <duwe@suse.de> | |
5 | ## Copyright (C) 2014 Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com> | |
6 | ## | |
7 | ## This program is free software; you can redistribute it and/or modify | |
8 | ## it under the terms of the GNU General Public License as published by | |
9 | ## the Free Software Foundation; either version 2 of the License, or | |
10 | ## (at your option) any later version. | |
11 | ## | |
12 | ## This program is distributed in the hope that it will be useful, | |
13 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | ## GNU General Public License for more details. | |
16 | ## | |
17 | ## You should have received a copy of the GNU General Public License | |
18 | ## along with this program; if not, write to the Free Software | |
19 | ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | ## | |
21 | ||
22 | import sigrokdecode as srd | |
23 | ||
24 | class SamplerateError(Exception): | |
25 | pass | |
26 | ||
27 | def normalize_time(t): | |
28 | if t >= 1.0: | |
29 | return '%.3f s' % t | |
30 | elif t >= 0.001: | |
31 | return '%.3f ms' % (t * 1000.0) | |
32 | elif t >= 0.000001: | |
33 | return '%.3f μs' % (t * 1000.0 * 1000.0) | |
34 | elif t >= 0.000000001: | |
35 | return '%.3f ns' % (t * 1000.0 * 1000.0 * 1000.0) | |
36 | else: | |
37 | return '%f' % t | |
38 | ||
39 | class Decoder(srd.Decoder): | |
40 | api_version = 2 | |
41 | id = 'timing' | |
42 | name = 'Timing' | |
43 | longname = 'Timing calculation' | |
44 | desc = 'Calculate time between edges.' | |
45 | license = 'gplv2+' | |
46 | inputs = ['logic'] | |
47 | outputs = ['timing'] | |
48 | channels = ( | |
49 | {'id': 'data', 'name': 'Data', 'desc': 'Data line'}, | |
50 | ) | |
51 | annotations = ( | |
52 | ('time', 'Time'), | |
53 | ) | |
54 | annotation_rows = ( | |
55 | ('time', 'Time', (0,)), | |
56 | ) | |
57 | ||
58 | def __init__(self, **kwargs): | |
59 | self.samplerate = None | |
60 | self.oldpin = None | |
61 | self.last_samplenum = None | |
62 | ||
63 | def metadata(self, key, value): | |
64 | if key == srd.SRD_CONF_SAMPLERATE: | |
65 | self.samplerate = value | |
66 | ||
67 | def start(self): | |
68 | self.out_ann = self.register(srd.OUTPUT_ANN) | |
69 | ||
70 | def decode(self, ss, es, data): | |
71 | if not self.samplerate: | |
72 | raise SamplerateError('Cannot decode without samplerate.') | |
73 | ||
74 | for (samplenum, (pin,)) in data: | |
75 | # Ignore identical samples early on (for performance reasons). | |
76 | if self.oldpin == pin: | |
77 | continue | |
78 | ||
79 | if self.oldpin is None: | |
80 | self.oldpin = pin | |
81 | self.last_samplenum = samplenum | |
82 | continue | |
83 | ||
84 | if self.oldpin != pin: | |
85 | samples = samplenum - self.last_samplenum | |
86 | t = samples / self.samplerate | |
87 | ||
88 | # Report the timing normalized. | |
89 | self.put(self.last_samplenum, samplenum, self.out_ann, | |
90 | [0, [normalize_time(t)]]) | |
91 | ||
92 | # Store data for next round. | |
93 | self.last_samplenum = samplenum | |
94 | self.oldpin = pin |