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).')
50 if self.options['direction'] not in ('both', 'read', 'write'):
51 raise Exception('Invalid direction (valid: read/write/both).')
53 # Grab I²C packets into a local cache, until an I²C STOP condition
54 # packet comes along. At some point before that STOP condition, there
55 # will have been an ADDRESS READ or ADDRESS WRITE which contains the
56 # I²C address of the slave that the master wants to talk to.
57 # If that slave shall be filtered, output the cache (all packets from
58 # START to STOP) as proto 'i2c', otherwise drop it.
59 def decode(self, ss, es, data):
63 # Add the I²C packet to our local cache.
64 self.packets.append([ss, es, data])
66 if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
67 self.curslave = databyte
68 self.curdirection = cmd[8:].lower()
69 elif cmd in ('STOP', 'START REPEAT'):
70 # If this chunk was not for the correct slave, drop it.
71 if self.options['address'] == 0:
73 elif self.curslave != self.options['address']:
77 # If this chunk was not in the right direction, drop it.
78 if self.options['direction'] == 'both':
80 elif self.options['direction'] != self.curdirection:
84 # TODO: START->STOP chunks with both read and write (Repeat START)
85 # Otherwise, send out the whole chunk of I²C packets.
86 for p in self.packets:
87 self.put(p[0], p[1], self.out_python, p[2])
91 pass # Do nothing, only add the I²C packet to our cache.