forked from Ivasoft/DSView
94 lines
3.4 KiB
Python
Executable File
94 lines
3.4 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 Bert Vermeulen <bert@biot.com>
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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 3 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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# TODO: Support for filtering out multiple slave/direction pairs?
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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 = 'i2cfilter'
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name = 'I²C filter'
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longname = 'I²C filter'
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desc = 'Filter out addresses/directions in an I²C stream.'
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license = 'gplv3+'
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inputs = ['i2c']
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outputs = ['i2c']
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tags = ['Util']
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options = (
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{'id': 'address', 'desc': 'Address to filter out of the I²C stream',
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'default': 0},
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{'id': 'direction', 'desc': 'Direction to filter', 'default': 'both',
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'values': ('read', 'write', 'both')}
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)
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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.curslave = -1
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self.curdirection = None
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self.packets = [] # Local cache of I²C packets
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def start(self):
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self.out_python = self.register(srd.OUTPUT_PYTHON, proto_id='i2c')
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if self.options['address'] not in range(0, 127 + 1):
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raise Exception('Invalid slave (must be 0..127).')
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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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# If that slave shall be filtered, output the cache (all packets from
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# START to STOP) as proto 'i2c', otherwise drop it.
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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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self.curslave = databyte
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self.curdirection = cmd[8:].lower()
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elif cmd in ('STOP', 'START REPEAT'):
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# If this chunk was not for the correct slave, drop it.
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if self.options['address'] == 0:
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pass
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elif self.curslave != self.options['address']:
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self.packets = []
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return
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# If this chunk was not in the right direction, drop it.
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if self.options['direction'] == 'both':
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pass
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elif self.options['direction'] != self.curdirection:
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self.packets = []
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return
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# TODO: START->STOP chunks with both read and write (Repeat START)
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# Otherwise, send out the whole chunk of I²C packets.
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for p in self.packets:
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self.put(p[0], p[1], self.out_python, p[2])
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self.packets = []
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else:
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pass # Do nothing, only add the I²C packet to our cache.
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