projects / libsigrokdecode.git / blame
| Commit | Line | Data |
|---|---|---|
| 61c2bd36 BV |
1 | ## |
| 2 | ## This file is part of the sigrok project. | |
| 3 | ## | |
| 4 | ## Copyright (C) 2012 Bert Vermeulen <bert@biot.com> | |
| 5 | ## | |
| 6 | ## This program is free software; you can redistribute it and/or modify | |
| 7 | ## it under the terms of the GNU General Public License as published by | |
| 8 | ## the Free Software Foundation; either version 3 of the License, or | |
| 9 | ## (at your option) any later version. | |
| 10 | ## | |
| 11 | ## This program is distributed in the hope that it will be useful, | |
| 12 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 14 | ## GNU General Public License for more details. | |
| 15 | ## | |
| 16 | ## You should have received a copy of the GNU General Public License | |
| 17 | ## along with this program; if not, see <http://www.gnu.org/licenses/>. | |
| 18 | ## | |
| 19 | ||
| 156509ca | 20 | # Generic I2C filtering protocol decoder |
| 61c2bd36 | 21 | |
| 156509ca | 22 | import sigrokdecode as srd |
| 61c2bd36 BV |
23 | |
| 24 | class Decoder(srd.Decoder): | |
| 25 | api_version = 1 | |
| 26 | id = 'i2cfilter' | |
| 27 | name = 'I2C filter' | |
| 28 | longname = 'I2C filter' | |
| 29 | desc = 'Filter out specific addresses/directions in an I2C stream.' | |
| 30 | license = 'gplv3+' | |
| 31 | inputs = ['i2c'] | |
| 32 | outputs = [] | |
| 33 | options = { | |
| 34 | 'address': ['Address to filter out of the I2C stream', 0], | |
| 35 | 'direction': ['Direction to filter (read/write)', ''] | |
| 36 | } | |
| 37 | ||
| 38 | def __init__(self, **kwargs): | |
| 39 | self.state = None | |
| 40 | ||
| 41 | def start(self, metadata): | |
| 42 | self.out_proto = self.add(srd.OUTPUT_PROTO, 'i2cdata') | |
| 43 | if self.options['direction'] not in ('', 'read', 'write'): | |
| 09059016 | 44 | raise Exception('Invalid direction: expected "read" or "write"') |
| 61c2bd36 | 45 | |
| 363252b4 UH |
46 | def report(self): |
| 47 | pass | |
| 48 | ||
| 61c2bd36 BV |
49 | def decode(self, ss, es, data): |
| 50 | try: | |
| 1b75abfd | 51 | cmd, data = data |
| 61c2bd36 BV |
52 | except Exception as e: |
| 53 | raise Exception('Malformed I2C input: %s' % str(e)) from e | |
| 54 | ||
| 55 | # Whichever state we're in, these always reset the state machine. | |
| 56 | # This should make it easier to deal with corrupt data etc. | |
| 57 | if cmd in ('START', 'START REPEAT'): | |
| 58 | self.state = 'start' | |
| 59 | return | |
| 60 | if cmd == 'STOP': | |
| 61 | self.state = None | |
| 62 | return | |
| 1b75abfd BV |
63 | if cmd in ('ACK', 'NACK'): |
| 64 | # Don't care, we just want data. | |
| 65 | return | |
| 61c2bd36 BV |
66 | |
| 67 | if self.state == 'start': | |
| 68 | # Start of a transfer, see if we want this one. | |
| 69 | if cmd == 'ADDRESS READ' and self.options['direction'] == 'write': | |
| 70 | return | |
| 71 | elif cmd == 'ADDRESS WRITE' and self.options['direction'] == 'read': | |
| 72 | return | |
| 73 | elif cmd in ('ADDRESS READ', 'ADDRESS WRITE'): | |
| 74 | if self.options['address'] in (0, data): | |
| 75 | # We want this tranfer. | |
| 76 | self.state = 'transfer' | |
| 77 | elif self.state == 'transfer': | |
| 78 | if cmd in ('DATA READ', 'DATA WRITE'): | |
| 79 | self.put(ss, es, self.out_proto, data) | |
| 80 | else: | |
| 81 | raise Exception('Invalid state: %s' % self.state) | |
| 82 |