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1 | ## | |
2 | ## This file is part of the libsigrokdecode project. | |
3 | ## | |
4 | ## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.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 sigrokdecode as srd | |
21 | ||
22 | class Decoder(srd.Decoder): | |
23 | api_version = 3 | |
24 | id = 'i2cdemux' | |
25 | name = 'I²C demux' | |
26 | longname = 'I²C demultiplexer' | |
27 | desc = 'Demux I²C packets into per-slave-address streams.' | |
28 | license = 'gplv2+' | |
29 | inputs = ['i2c'] | |
30 | outputs = [] # TODO: Only known at run-time. | |
31 | ||
32 | def __init__(self): | |
33 | self.reset() | |
34 | ||
35 | def reset(self): | |
36 | self.packets = [] # Local cache of I²C packets | |
37 | self.slaves = [] # List of known slave addresses | |
38 | self.stream = -1 # Current output stream | |
39 | self.streamcount = 0 # Number of created output streams | |
40 | ||
41 | def start(self): | |
42 | self.out_python = [] | |
43 | ||
44 | # Grab I²C packets into a local cache, until an I²C STOP condition | |
45 | # packet comes along. At some point before that STOP condition, there | |
46 | # will have been an ADDRESS READ or ADDRESS WRITE which contains the | |
47 | # I²C address of the slave that the master wants to talk to. | |
48 | # We use this slave address to figure out which output stream should | |
49 | # get the whole chunk of packets (from START to STOP). | |
50 | def decode(self, ss, es, data): | |
51 | ||
52 | cmd, databyte = data | |
53 | ||
54 | # Add the I²C packet to our local cache. | |
55 | self.packets.append([ss, es, data]) | |
56 | ||
57 | if cmd in ('ADDRESS READ', 'ADDRESS WRITE'): | |
58 | if databyte in self.slaves: | |
59 | self.stream = self.slaves.index(databyte) | |
60 | return | |
61 | ||
62 | # We're never seen this slave, add a new stream. | |
63 | self.slaves.append(databyte) | |
64 | self.out_python.append(self.register(srd.OUTPUT_PYTHON, | |
65 | proto_id='i2c-%s' % hex(databyte))) | |
66 | self.stream = self.streamcount | |
67 | self.streamcount += 1 | |
68 | elif cmd == 'STOP': | |
69 | if self.stream == -1: | |
70 | raise Exception('Invalid stream!') # FIXME? | |
71 | ||
72 | # Send the whole chunk of I²C packets to the correct stream. | |
73 | for p in self.packets: | |
74 | self.put(p[0], p[1], self.out_python[self.stream], p[2]) | |
75 | ||
76 | self.packets = [] | |
77 | self.stream = -1 | |
78 | else: | |
79 | pass # Do nothing, only add the I²C packet to our cache. |