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 # Generic I2C filtering protocol decoder
23 # TODO: Support for filtering out multiple slave/direction pairs?
25 import sigrokdecode as srd
27 class Decoder(srd.Decoder):
31 longname = 'I2C filter'
32 desc = 'Filter out addresses/directions in an I2C stream.'
39 'address': ['Address to filter out of the I2C stream', 0],
40 'direction': ['Direction to filter (read/write/both)', 'both']
44 def __init__(self, **kwargs):
47 self.curdirection = None
48 self.packets = [] # Local cache of I2C packets
50 def start(self, metadata):
51 self.out_proto = self.add(srd.OUTPUT_PROTO, 'i2c')
52 if self.options['address'] not in range(0, 127 + 1):
53 raise Exception('Invalid slave (must be 0..127).')
54 if self.options['direction'] not in ('both', 'read', 'write'):
55 raise Exception('Invalid direction (valid: read/write/both).')
60 # Grab I2C packets into a local cache, until an I2C STOP condition
61 # packet comes along. At some point before that STOP condition, there
62 # will have been an ADDRESS READ or ADDRESS WRITE which contains the
63 # I2C address of the slave that the master wants to talk to.
64 # If that slave shall be filtered, output the cache (all packets from
65 # START to STOP) as proto 'i2c', otherwise drop it.
66 def decode(self, ss, es, data):
70 # Add the I2C packet to our local cache.
71 self.packets.append([ss, es, data])
73 if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
74 self.curslave = databyte
75 self.curdirection = cmd[8:].lower()
76 elif cmd in ('STOP', 'START REPEAT'):
77 # If this chunk was not for the correct slave, drop it.
78 if self.options['address'] == 0:
80 elif self.curslave != self.options['address']:
84 # If this chunk was not in the right direction, drop it.
85 if self.options['direction'] == 'both':
87 elif self.options['direction'] != self.curdirection:
91 # TODO: START->STOP chunks with both read and write (Repeat START)
92 # Otherwise, send out the whole chunk of I2C packets.
93 for p in self.packets:
94 self.put(p[0], p[1], self.out_proto, p[2])
98 pass # Do nothing, only add the I2C packet to our cache.