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81 lines
2.9 KiB
Python
Executable File
81 lines
2.9 KiB
Python
Executable File
##
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## This file is part of the libsigrokdecode project.
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##
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## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
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##
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## This program is free software; you can redistribute it and/or modify
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## it under the terms of the GNU General Public License as published by
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## the Free Software Foundation; either version 2 of the License, or
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## (at your option) any later version.
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##
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## This program is distributed in the hope that it will be useful,
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## but WITHOUT ANY WARRANTY; without even the implied warranty of
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## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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## GNU General Public License for more details.
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##
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## You should have received a copy of the GNU General Public License
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## along with this program; if not, see <http://www.gnu.org/licenses/>.
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##
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import sigrokdecode as srd
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class Decoder(srd.Decoder):
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api_version = 3
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id = 'i2cdemux'
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name = 'I²C demux'
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longname = 'I²C demultiplexer'
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desc = 'Demux I²C packets into per-slave-address streams.'
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license = 'gplv2+'
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inputs = ['i2c']
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outputs = [] # TODO: Only known at run-time.
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tags = ['Util']
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def __init__(self):
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self.reset()
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def reset(self):
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self.packets = [] # Local cache of I²C packets
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self.slaves = [] # List of known slave addresses
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self.stream = -1 # Current output stream
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self.streamcount = 0 # Number of created output streams
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def start(self):
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self.out_python = []
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# Grab I²C packets into a local cache, until an I²C STOP condition
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# packet comes along. At some point before that STOP condition, there
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# will have been an ADDRESS READ or ADDRESS WRITE which contains the
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# I²C address of the slave that the master wants to talk to.
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# We use this slave address to figure out which output stream should
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# get the whole chunk of packets (from START to STOP).
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def decode(self, ss, es, data):
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cmd, databyte = data
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# Add the I²C packet to our local cache.
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self.packets.append([ss, es, data])
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if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
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if databyte in self.slaves:
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self.stream = self.slaves.index(databyte)
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return
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# We're never seen this slave, add a new stream.
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self.slaves.append(databyte)
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self.out_python.append(self.register(srd.OUTPUT_PYTHON,
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proto_id='i2c-%s' % hex(databyte)))
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self.stream = self.streamcount
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self.streamcount += 1
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elif cmd == 'STOP':
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if self.stream == -1:
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raise Exception('Invalid stream!') # FIXME?
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# Send the whole chunk of I²C packets to the correct stream.
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for p in self.packets:
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self.put(p[0], p[1], self.out_python[self.stream], p[2])
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self.packets = []
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self.stream = -1
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else:
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pass # Do nothing, only add the I²C packet to our cache.
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