2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
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.
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.
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
21 # Generic I2C demultiplexing protocol decoder
23 import sigrokdecode as srd
25 class Decoder(srd.Decoder):
29 longname = 'I2C demultiplexer'
30 desc = 'Demux I2C packets into per-slave-address streams.'
33 outputs = [] # TODO: Only known at run-time.
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
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):
61 # Add the I2C packet to our local cache.
62 self.packets.append([ss, es, data])
64 if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
65 if databyte in self.slaves:
66 self.stream = self.slaves.index(databyte)
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_PYTHON,
72 'i2c-%s' % hex(databyte)))
73 self.stream = self.streamcount
77 raise Exception('Invalid stream!') # FIXME?
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])
86 pass # Do nothing, only add the I2C packet to our cache.