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1 | ## | |
2 | ## This file is part of the sigrok 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, write to the Free Software | |
18 | ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | ## | |
20 | ||
21 | # Generic I2C demultiplexing protocol decoder | |
22 | ||
23 | import sigrokdecode as srd | |
24 | ||
25 | class Decoder(srd.Decoder): | |
26 | api_version = 1 | |
27 | id = 'i2cdemux' | |
28 | name = 'I2C demux' | |
29 | longname = 'I2C demultiplexer' | |
30 | desc = 'Demux I2C packets into per-slave-address streams.' | |
31 | license = 'gplv2+' | |
32 | inputs = ['i2c'] | |
33 | outputs = [] # TODO: Only known at run-time. | |
34 | probes = [] | |
35 | optional_probes = [] | |
36 | options = {} | |
37 | annotations = [] | |
38 | ||
39 | def __init__(self, **kwargs): | |
40 | self.packets = [] # Local cache of I2C packets | |
41 | self.slaves = [] # List of known slave addresses | |
42 | self.stream = -1 # Current output stream | |
43 | self.streamcount = 0 # Number of created output streams | |
44 | ||
45 | def start(self, metadata): | |
46 | self.out_proto = [] | |
47 | ||
48 | def report(self): | |
49 | pass | |
50 | ||
51 | # Grab I2C packets into a local cache, until an I2C STOP condition | |
52 | # packet comes along. At some point before that STOP condition, there | |
53 | # will have been an ADDRESS READ or ADDRESS WRITE which contains the | |
54 | # I2C address of the slave that the master wants to talk to. | |
55 | # We use this slave address to figure out which output stream should | |
56 | # get the whole chunk of packets (from START to STOP). | |
57 | def decode(self, ss, es, data): | |
58 | ||
59 | cmd, databyte = data | |
60 | ||
61 | # Add the I2C packet to our local cache. | |
62 | self.packets.append([ss, es, data]) | |
63 | ||
64 | if cmd in ('ADDRESS READ', 'ADDRESS WRITE'): | |
65 | if databyte in self.slaves: | |
66 | self.stream = self.slaves.index(databyte) | |
67 | return | |
68 | ||
69 | # We're never seen this slave, add a new stream. | |
70 | self.slaves.append(databyte) | |
71 | self.out_proto.append(self.add(srd.OUTPUT_PROTO, | |
72 | 'i2c-%s' % hex(databyte))) | |
73 | self.stream = self.streamcount | |
74 | self.streamcount += 1 | |
75 | elif cmd == 'STOP': | |
76 | if self.stream == -1: | |
77 | raise Exception('Invalid stream!') # FIXME? | |
78 | ||
79 | # Send the whole chunk of I2C packets to the correct stream. | |
80 | for p in self.packets: | |
81 | self.put(p[0], p[1], self.out_proto[self.stream], p[2]) | |
82 | ||
83 | self.packets = [] | |
84 | self.stream = -1 | |
85 | else: | |
86 | pass # Do nothing, only add the I2C packet to our cache. | |
87 |