decoders/em4100/pd.py

   1 ##
   2 ## This file is part of the libsigrokdecode project.
   3 ##
   4 ## Copyright (C) 2015 Benjamin Larsson <benjamin@southpole.se>
   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 class SamplerateError(Exception):
  23     pass
  24
  25 class Decoder(srd.Decoder):
  26     api_version = 3
  27     id = 'em4100'
  28     name = 'EM4100'
  29     longname = 'RFID EM4100'
  30     desc = 'EM4100 100-150kHz RFID protocol.'
  31     license = 'gplv2+'
  32     inputs = ['logic']
  33     outputs = []
  34     tags = ['IC', 'RFID']
  35     channels = (
  36         {'id': 'data', 'name': 'Data', 'desc': 'Data line'},
  37     )
  38     options = (
  39         {'id': 'polarity', 'desc': 'Polarity', 'default': 'active-high',
  40             'values': ('active-low', 'active-high')},
  41         {'id': 'datarate' , 'desc': 'Data rate', 'default': 64,
  42             'values': (64, 32, 16)},
  43 #        {'id': 'coding', 'desc': 'Bit coding', 'default': 'biphase',
  44 #            'values': ('biphase', 'manchester', 'psk')},
  45         {'id': 'coilfreq', 'desc': 'Coil frequency', 'default': 125000},
  46     )
  47     annotations = (
  48         ('bit', 'Bit'),
  49         ('header', 'Header'),
  50         ('version-customer', 'Version/customer'),
  51         ('data', 'Data'),
  52         ('rowparity-ok', 'Row parity OK'),
  53         ('rowparity-err', 'Row parity error'),
  54         ('colparity-ok', 'Column parity OK'),
  55         ('colparity-err', 'Column parity error'),
  56         ('stopbit', 'Stop bit'),
  57         ('tag', 'Tag'),
  58     )
  59     annotation_rows = (
  60         ('bits', 'Bits', (0,)),
  61         ('fields', 'Fields', (1, 2, 3, 4, 5, 6, 7, 8)),
  62         ('tags', 'Tags', (9,)),
  63     )
  64
  65     def __init__(self):
  66         self.reset()
  67
  68     def reset(self):
  69         self.samplerate = None
  70         self.oldpin = None
  71         self.last_samplenum = None
  72         self.lastlast_samplenum = None
  73         self.last_edge = 0
  74         self.bit_width = 0
  75         self.halfbit_limit = 0
  76         self.oldpp = 0
  77         self.oldpl = 0
  78         self.oldsamplenum = 0
  79         self.last_bit_pos = 0
  80         self.ss_first = 0
  81         self.first_one = 0
  82         self.state = 'HEADER'
  83         self.data = 0
  84         self.data_bits = 0
  85         self.ss_data = 0
  86         self.data_parity = 0
  87         self.payload_cnt = 0
  88         self.data_col_parity = [0, 0, 0, 0, 0, 0]
  89         self.col_parity = [0, 0, 0, 0, 0, 0]
  90         self.tag = 0
  91         self.all_row_parity_ok = True
  92         self.col_parity_pos = []
  93
  94     def metadata(self, key, value):
  95         if key == srd.SRD_CONF_SAMPLERATE:
  96             self.samplerate = value
  97         self.bit_width = (self.samplerate / self.options['coilfreq']) * self.options['datarate']
  98         self.halfbit_limit = self.bit_width/2 + self.bit_width/4
  99         self.polarity = 0 if self.options['polarity'] == 'active-low' else 1
 100
 101     def start(self):
 102         self.out_ann = self.register(srd.OUTPUT_ANN)
 103
 104     def putbit(self, bit, ss, es):
 105         self.put(ss, es, self.out_ann, [0, [str(bit)]])
 106         if self.state == 'HEADER':
 107             if bit == 1:
 108                 if self.first_one > 0:
 109                     self.first_one += 1
 110                 if self.first_one == 9:
 111                     self.put(self.ss_first, es, self.out_ann,
 112                              [1, ['Header', 'Head', 'He', 'H']])
 113                     self.first_one = 0
 114                     self.state = 'PAYLOAD'
 115                     return
 116                 if self.first_one == 0:
 117                     self.first_one = 1
 118                     self.ss_first = ss
 119
 120             if bit == 0:
 121                 self.first_one = 0
 122             return
 123
 124         if self.state == 'PAYLOAD':
 125             self.payload_cnt += 1
 126             if self.data_bits == 0:
 127                 self.ss_data = ss
 128                 self.data = 0
 129                 self.data_parity = 0
 130             self.data_bits += 1
 131             if self.data_bits == 5:
 132                 s = 'Version/customer' if self.payload_cnt <= 10 else 'Data'
 133                 c = 2 if self.payload_cnt <= 10 else 3
 134                 self.put(self.ss_data, ss, self.out_ann,
 135                          [c, [s + ': %X' % self.data, '%X' % self.data]])
 136                 s = 'OK' if self.data_parity == bit else 'ERROR'
 137                 c = 4 if s == 'OK' else 5
 138                 if s == 'ERROR':
 139                     self.all_row_parity_ok = False
 140                 self.put(ss, es, self.out_ann,
 141                          [c, ['Row parity: ' + s, 'RP: ' + s, 'RP', 'R']])
 142                 self.tag = (self.tag << 4) | self.data
 143                 self.data_bits = 0
 144                 if self.payload_cnt == 50:
 145                     self.state = 'TRAILER'
 146                     self.payload_cnt = 0
 147
 148             self.data_parity ^= bit
 149             self.data_col_parity[self.data_bits] ^= bit
 150             self.data = (self.data << 1) | bit
 151             return
 152
 153         if self.state == 'TRAILER':
 154             self.payload_cnt += 1
 155             if self.data_bits == 0:
 156                 self.ss_data = ss
 157                 self.data = 0
 158                 self.data_parity = 0
 159             self.data_bits += 1
 160             self.col_parity[self.data_bits] = bit
 161             self.col_parity_pos.append([ss, es])
 162
 163             if self.data_bits == 5:
 164                 self.put(ss, es, self.out_ann, [8, ['Stop bit', 'SB', 'S']])
 165
 166                 for i in range(1, 5):
 167                     s = 'OK' if self.data_col_parity[i] == \
 168                                 self.col_parity[i] else 'ERROR'
 169                     c = 6 if s == 'OK' else 7
 170                     self.put(self.col_parity_pos[i - 1][0],
 171                              self.col_parity_pos[i - 1][1], self.out_ann,
 172                              [c, ['Column parity %d: %s' % (i, s),
 173                                   'CP%d: %s' % (i, s), 'CP%d' % i, 'C']])
 174
 175                 # Emit an annotation for valid-looking tags.
 176                 all_col_parity_ok = (self.data_col_parity[1:5] == self.col_parity[1:5])
 177                 if all_col_parity_ok and self.all_row_parity_ok:
 178                     self.put(self.ss_first, es, self.out_ann,
 179                              [9, ['Tag: %010X' % self.tag, 'Tag', 'T']])
 180
 181                 self.tag = 0
 182                 self.data_bits = 0
 183
 184                 if self.payload_cnt == 5:
 185                     self.state = 'HEADER'
 186                     self.payload_cnt = 0
 187                     self.data_col_parity = [0, 0, 0, 0, 0, 0]
 188                     self.col_parity = [0, 0, 0, 0, 0, 0]
 189                     self.col_parity_pos = []
 190                     self.all_row_parity_ok = True
 191
 192     def manchester_decode(self, pl, pp, pin):
 193         bit = self.oldpin ^ self.polarity
 194         if pl > self.halfbit_limit:
 195             es = int(self.samplenum - pl/2)
 196             if self.oldpl > self.halfbit_limit:
 197                 ss = int(self.oldsamplenum - self.oldpl/2)
 198             else:
 199                 ss = int(self.oldsamplenum - self.oldpl)
 200             self.putbit(bit, ss, es)
 201             self.last_bit_pos = int(self.samplenum - pl/2)
 202         else:
 203             es = int(self.samplenum)
 204             if self.oldpl > self.halfbit_limit:
 205                 ss = int(self.oldsamplenum - self.oldpl/2)
 206                 self.putbit(bit, ss, es)
 207                 self.last_bit_pos = int(self.samplenum)
 208             else:
 209                 if self.last_bit_pos <= self.oldsamplenum - self.oldpl:
 210                     ss = int(self.oldsamplenum - self.oldpl)
 211                     self.putbit(bit, ss, es)
 212                     self.last_bit_pos = int(self.samplenum)
 213
 214     def decode(self):
 215         if not self.samplerate:
 216             raise SamplerateError('Cannot decode without samplerate.')
 217
 218         # Initialize internal state from the very first sample.
 219         (pin,) = self.wait()
 220         self.oldpin = pin
 221         self.last_samplenum = self.samplenum
 222         self.lastlast_samplenum = self.samplenum
 223         self.last_edge = self.samplenum
 224         self.oldpl = 0
 225         self.oldpp = 0
 226         self.oldsamplenum = 0
 227         self.last_bit_pos = 0
 228
 229         while True:
 230             # Ignore identical samples, only process edges.
 231             (pin,) = self.wait({0: 'e'})
 232             pl = self.samplenum - self.oldsamplenum
 233             pp = pin
 234             self.manchester_decode(pl, pp, pin)
 235             self.oldpl = pl
 236             self.oldpp = pp
 237             self.oldsamplenum = self.samplenum
 238             self.oldpin = pin