decoders/onewire_network/pd.py

   1 ##
   2 ## This file is part of the libsigrokdecode project.
   3 ##
   4 ## Copyright (C) 2012 Iztok Jeras <iztok.jeras@gmail.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 2 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
  20 import sigrokdecode as srd
  21
  22 # Dictionary of ROM commands and their names, next state.
  23 command = {
  24     0x33: ['Read ROM'                  , 'GET ROM'   ],
  25     0x0f: ['Conditional read ROM'      , 'GET ROM'   ],
  26     0xcc: ['Skip ROM'                  , 'TRANSPORT' ],
  27     0x55: ['Match ROM'                 , 'GET ROM'   ],
  28     0xf0: ['Search ROM'                , 'SEARCH ROM'],
  29     0xec: ['Conditional search ROM'    , 'SEARCH ROM'],
  30     0x3c: ['Overdrive skip ROM'        , 'TRANSPORT' ],
  31     0x69: ['Overdrive match ROM'       , 'GET ROM'   ],
  32     0xa5: ['Resume'                    , 'TRANSPORT' ],
  33     0x96: ['DS2408: Disable Test Mode' , 'GET ROM'   ],
  34 }
  35
  36 class Decoder(srd.Decoder):
  37     api_version = 3
  38     id = 'onewire_network'
  39     name = '1-Wire network layer'
  40     longname = '1-Wire serial communication bus (network layer)'
  41     desc = 'Bidirectional, half-duplex, asynchronous serial bus.'
  42     license = 'gplv2+'
  43     inputs = ['onewire_link']
  44     outputs = ['onewire_network']
  45     tags = ['Embedded/industrial']
  46     annotations = (
  47         ('text', 'Text'),
  48     )
  49
  50     def __init__(self):
  51         self.reset()
  52
  53     def reset(self):
  54         self.ss_block = 0
  55         self.es_block = 0
  56         self.state = 'COMMAND'
  57         self.bit_cnt = 0
  58         self.search = 'P'
  59         self.data_p = 0x0
  60         self.data_n = 0x0
  61         self.data = 0x0
  62         self.rom = 0x0000000000000000
  63
  64     def start(self):
  65         self.out_python = self.register(srd.OUTPUT_PYTHON)
  66         self.out_ann = self.register(srd.OUTPUT_ANN)
  67
  68     def putx(self, data):
  69         # Helper function for most annotations.
  70         self.put(self.ss_block, self.es_block, self.out_ann, data)
  71
  72     def puty(self, data):
  73         # Helper function for most protocol packets.
  74         self.put(self.ss_block, self.es_block, self.out_python, data)
  75
  76     def decode(self, ss, es, data):
  77         code, val = data
  78
  79         # State machine.
  80         if code == 'RESET/PRESENCE':
  81             self.search = 'P'
  82             self.bit_cnt = 0
  83             self.put(ss, es, self.out_ann,
  84                      [0, ['Reset/presence: %s' % ('true' if val else 'false')]])
  85             self.put(ss, es, self.out_python, ['RESET/PRESENCE', val])
  86             self.state = 'COMMAND'
  87             return
  88
  89         # For now we're only interested in 'RESET/PRESENCE' and 'BIT' packets.
  90         if code != 'BIT':
  91             return
  92
  93         if self.state == 'COMMAND':
  94             # Receiving and decoding a ROM command.
  95             if self.onewire_collect(8, val, ss, es) == 0:
  96                 return
  97             if self.data in command:
  98                 self.putx([0, ['ROM command: 0x%02x \'%s\''
  99                           % (self.data, command[self.data][0])]])
 100                 self.state = command[self.data][1]
 101             else:
 102                 self.putx([0, ['ROM command: 0x%02x \'%s\''
 103                           % (self.data, 'unrecognized')]])
 104                 self.state = 'COMMAND ERROR'
 105         elif self.state == 'GET ROM':
 106             # A 64 bit device address is selected.
 107             # Family code (1 byte) + serial number (6 bytes) + CRC (1 byte)
 108             if self.onewire_collect(64, val, ss, es) == 0:
 109                 return
 110             self.rom = self.data & 0xffffffffffffffff
 111             self.putx([0, ['ROM: 0x%016x' % self.rom]])
 112             self.puty(['ROM', self.rom])
 113             self.state = 'TRANSPORT'
 114         elif self.state == 'SEARCH ROM':
 115             # A 64 bit device address is searched for.
 116             # Family code (1 byte) + serial number (6 bytes) + CRC (1 byte)
 117             if self.onewire_search(64, val, ss, es) == 0:
 118                 return
 119             self.rom = self.data & 0xffffffffffffffff
 120             self.putx([0, ['ROM: 0x%016x' % self.rom]])
 121             self.puty(['ROM', self.rom])
 122             self.state = 'TRANSPORT'
 123         elif self.state == 'TRANSPORT':
 124             # The transport layer is handled in byte sized units.
 125             if self.onewire_collect(8, val, ss, es) == 0:
 126                 return
 127             self.putx([0, ['Data: 0x%02x' % self.data]])
 128             self.puty(['DATA', self.data])
 129         elif self.state == 'COMMAND ERROR':
 130             # Since the command is not recognized, print raw data.
 131             if self.onewire_collect(8, val, ss, es) == 0:
 132                 return
 133             self.putx([0, ['ROM error data: 0x%02x' % self.data]])
 134
 135     # Data collector.
 136     def onewire_collect(self, length, val, ss, es):
 137         # Storing the sample this sequence begins with.
 138         if self.bit_cnt == 0:
 139             self.ss_block = ss
 140         self.data = self.data & ~(1 << self.bit_cnt) | (val << self.bit_cnt)
 141         self.bit_cnt += 1
 142         # Storing the sample this sequence ends with.
 143         # In case the full length of the sequence is received, return 1.
 144         if self.bit_cnt == length:
 145             self.es_block = es
 146             self.data = self.data & ((1 << length) - 1)
 147             self.bit_cnt = 0
 148             return 1
 149         else:
 150             return 0
 151
 152     # Search collector.
 153     def onewire_search(self, length, val, ss, es):
 154         # Storing the sample this sequence begins with.
 155         if (self.bit_cnt == 0) and (self.search == 'P'):
 156             self.ss_block = ss
 157
 158         if self.search == 'P':
 159             # Master receives an original address bit.
 160             self.data_p = self.data_p & ~(1 << self.bit_cnt) | \
 161                           (val << self.bit_cnt)
 162             self.search = 'N'
 163         elif self.search == 'N':
 164             # Master receives a complemented address bit.
 165             self.data_n = self.data_n & ~(1 << self.bit_cnt) | \
 166                           (val << self.bit_cnt)
 167             self.search = 'D'
 168         elif self.search == 'D':
 169             # Master transmits an address bit.
 170             self.data = self.data & ~(1 << self.bit_cnt) | (val << self.bit_cnt)
 171             self.search = 'P'
 172             self.bit_cnt += 1
 173
 174         # Storing the sample this sequence ends with.
 175         # In case the full length of the sequence is received, return 1.
 176         if self.bit_cnt == length:
 177             self.es_block = es
 178             self.data_p = self.data_p & ((1 << length) - 1)
 179             self.data_n = self.data_n & ((1 << length) - 1)
 180             self.data = self.data & ((1 << length) - 1)
 181             self.search = 'P'
 182             self.bit_cnt = 0
 183             return 1
 184         else:
 185             return 0