2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
5 ## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
7 ## This program is free software; you can redistribute it and/or modify
8 ## it under the terms of the GNU General Public License as published by
9 ## the Free Software Foundation; either version 3 of the License, or
10 ## (at your option) any later version.
12 ## This program is distributed in the hope that it will be useful,
13 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
14 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 ## GNU General Public License for more details.
17 ## You should have received a copy of the GNU General Public License
18 ## along with this program; if not, see <http://www.gnu.org/licenses/>.
21 # TODO: Support for filtering out multiple slave/direction pairs?
23 import sigrokdecode as srd
25 class Decoder(srd.Decoder):
29 longname = 'I²C filter'
30 desc = 'Filter out addresses/directions in an I²C stream.'
35 {'id': 'address', 'desc': 'Address to filter out of the I²C stream',
37 {'id': 'direction', 'desc': 'Direction to filter', 'default': 'both',
38 'values': ('read', 'write', 'both')}
41 def __init__(self, **kwargs):
43 self.curdirection = None
44 self.packets = [] # Local cache of I²C packets
47 self.out_python = self.register(srd.OUTPUT_PYTHON, proto_id='i2c')
48 if self.options['address'] not in range(0, 127 + 1):
49 raise Exception('Invalid slave (must be 0..127).')
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 # If that slave shall be filtered, output the cache (all packets from
56 # START to STOP) as proto 'i2c', otherwise drop it.
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 self.curslave = databyte
66 self.curdirection = cmd[8:].lower()
67 elif cmd in ('STOP', 'START REPEAT'):
68 # If this chunk was not for the correct slave, drop it.
69 if self.options['address'] == 0:
71 elif self.curslave != self.options['address']:
75 # If this chunk was not in the right direction, drop it.
76 if self.options['direction'] == 'both':
78 elif self.options['direction'] != self.curdirection:
82 # TODO: START->STOP chunks with both read and write (Repeat START)
83 # Otherwise, send out the whole chunk of I²C packets.
84 for p in self.packets:
85 self.put(p[0], p[1], self.out_python, p[2])
89 pass # Do nothing, only add the I²C packet to our cache.