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1 | ## | |
2 | ## This file is part of the sigrok project. | |
3 | ## | |
4 | ## Copyright (C) 2011 Gareth McMullin <gareth@blacksphere.co.nz> | |
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, write to the Free Software | |
18 | ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | ## | |
20 | ||
21 | import sigrok | |
22 | ||
23 | class Sample(): | |
24 | def __init__(self, data): | |
25 | self.data = data | |
26 | def probe(self, probe): | |
27 | s = ord(self.data[probe / 8]) & (1 << (probe % 8)) | |
28 | return True if s else False | |
29 | ||
30 | def sampleiter(data, unitsize): | |
31 | for i in range(0, len(data), unitsize): | |
32 | yield(Sample(data[i:i+unitsize])) | |
33 | ||
34 | class Decoder(sigrok.Decoder): | |
35 | id = 'spi' | |
36 | name = 'SPI' | |
37 | desc = '...desc...' | |
38 | longname = 'Serial Peripheral Interface (SPI) bus' | |
39 | longdesc = '...longdesc...' | |
40 | author = 'Gareth McMullin' | |
41 | email = 'gareth@blacksphere.co.nz' | |
42 | license = 'gplv2+' | |
43 | inputs = ['logic'] | |
44 | outputs = ['spi'] | |
45 | # Probe names with a set of defaults | |
46 | probes = {'sdata':0, 'sck':1} | |
47 | options = {} | |
48 | ||
49 | def __init__(self): | |
50 | self.probes = Decoder.probes.copy() | |
51 | self.oldsck = True | |
52 | self.rxcount = 0 | |
53 | self.rxdata = 0 | |
54 | self.bytesreceived = 0 | |
55 | ||
56 | def start(self, metadata): | |
57 | self.unitsize = metadata['unitsize'] | |
58 | ||
59 | def report(self): | |
60 | return 'SPI: %d bytes received' % self.bytesreceived | |
61 | ||
62 | def decode(self, data): | |
63 | # We should accept a list of samples and iterate... | |
64 | for sample in sampleiter(data['data'], self.unitsize): | |
65 | ||
66 | sck = sample.probe(self.probes['sck']) | |
67 | # Sample SDATA on rising SCK | |
68 | if sck == self.oldsck: | |
69 | continue | |
70 | self.oldsck = sck | |
71 | if not sck: | |
72 | continue | |
73 | ||
74 | # If this is first bit, save timestamp | |
75 | if self.rxcount == 0: | |
76 | self.time = data['time'] | |
77 | # Receive bit into our shift register | |
78 | sdata = sample.probe(self.probes['sdata']) | |
79 | if sdata: | |
80 | self.rxdata |= 1 << (7 - self.rxcount) | |
81 | self.rxcount += 1 | |
82 | # Continue to receive if not a byte yet | |
83 | if self.rxcount != 8: | |
84 | continue | |
85 | # Received a byte, pass up to sigrok | |
86 | outdata = {'time':self.time, | |
87 | 'duration':data['time'] + data['duration'] - self.time, | |
88 | 'data':self.rxdata, | |
89 | 'display':('%02X' % self.rxdata), | |
90 | 'type':'spi', | |
91 | } | |
92 | self.put(outdata) | |
93 | # Reset decoder state | |
94 | self.rxdata = 0 | |
95 | self.rxcount = 0 | |
96 | # Keep stats for summary | |
97 | self.bytesreceived += 1 | |
98 |