2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2015 Benjamin Larsson <benjamin@southpole.se>
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.
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.
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/>.
20 import sigrokdecode as srd
22 class SamplerateError(Exception):
25 class Decoder(srd.Decoder):
29 longname = 'RFID EM4100'
30 desc = 'EM4100 100-150kHz RFID protocol.'
35 {'id': 'data', 'name': 'Data', 'desc': 'Data line'},
38 {'id': 'polarity', 'desc': 'Polarity', 'default': 'active-high',
39 'values': ('active-low', 'active-high')},
40 {'id': 'datarate' , 'desc': 'Data rate', 'default': 64,
41 'values': (64, 32, 16)},
42 # {'id': 'coding', 'desc': 'Bit coding', 'default': 'biphase',
43 # 'values': ('biphase', 'manchester', 'psk')},
44 {'id': 'coilfreq', 'desc': 'Coil frequency', 'default': 125000},
49 ('version-customer', 'Version/customer'),
51 ('rowparity-ok', 'Row parity OK'),
52 ('rowparity-err', 'Row parity error'),
53 ('colparity-ok', 'Column parity OK'),
54 ('colparity-err', 'Column parity error'),
55 ('stopbit', 'Stop bit'),
59 ('bits', 'Bits', (0,)),
60 ('fields', 'Fields', (1, 2, 3, 4, 5, 6, 7, 8)),
61 ('tags', 'Tags', (9,)),
68 self.samplerate = None
70 self.last_samplenum = None
71 self.lastlast_samplenum = None
74 self.halfbit_limit = 0
87 self.data_col_parity = [0, 0, 0, 0, 0, 0]
88 self.col_parity = [0, 0, 0, 0, 0, 0]
90 self.all_row_parity_ok = True
91 self.col_parity_pos = []
93 def metadata(self, key, value):
94 if key == srd.SRD_CONF_SAMPLERATE:
95 self.samplerate = value
96 self.bit_width = (self.samplerate / self.options['coilfreq']) * self.options['datarate']
97 self.halfbit_limit = self.bit_width/2 + self.bit_width/4
98 self.polarity = 0 if self.options['polarity'] == 'active-low' else 1
101 self.out_ann = self.register(srd.OUTPUT_ANN)
103 def putbit(self, bit, ss, es):
104 self.put(ss, es, self.out_ann, [0, [str(bit)]])
105 if self.state == 'HEADER':
107 if self.first_one > 0:
109 if self.first_one == 9:
110 self.put(self.ss_first, es, self.out_ann,
111 [1, ['Header', 'Head', 'He', 'H']])
113 self.state = 'PAYLOAD'
115 if self.first_one == 0:
123 if self.state == 'PAYLOAD':
124 self.payload_cnt += 1
125 if self.data_bits == 0:
130 if self.data_bits == 5:
131 s = 'Version/customer' if self.payload_cnt <= 10 else 'Data'
132 c = 2 if self.payload_cnt <= 10 else 3
133 self.put(self.ss_data, ss, self.out_ann,
134 [c, [s + ': %X' % self.data, '%X' % self.data]])
135 s = 'OK' if self.data_parity == bit else 'ERROR'
136 c = 4 if s == 'OK' else 5
138 self.all_row_parity_ok = False
139 self.put(ss, es, self.out_ann,
140 [c, ['Row parity: ' + s, 'RP: ' + s, 'RP', 'R']])
141 self.tag = (self.tag << 4) | self.data
143 if self.payload_cnt == 50:
144 self.state = 'TRAILER'
147 self.data_parity ^= bit
148 self.data_col_parity[self.data_bits] ^= bit
149 self.data = (self.data << 1) | bit
152 if self.state == 'TRAILER':
153 self.payload_cnt += 1
154 if self.data_bits == 0:
159 self.col_parity[self.data_bits] = bit
160 self.col_parity_pos.append([ss, es])
162 if self.data_bits == 5:
163 self.put(ss, es, self.out_ann, [8, ['Stop bit', 'SB', 'S']])
165 for i in range(1, 5):
166 s = 'OK' if self.data_col_parity[i] == \
167 self.col_parity[i] else 'ERROR'
168 c = 6 if s == 'OK' else 7
169 self.put(self.col_parity_pos[i - 1][0],
170 self.col_parity_pos[i - 1][1], self.out_ann,
171 [c, ['Column parity %d: %s' % (i, s),
172 'CP%d: %s' % (i, s), 'CP%d' % i, 'C']])
174 # Emit an annotation for valid-looking tags.
175 all_col_parity_ok = (self.data_col_parity[1:5] == self.col_parity[1:5])
176 if all_col_parity_ok and self.all_row_parity_ok:
177 self.put(self.ss_first, es, self.out_ann,
178 [9, ['Tag: %010X' % self.tag, 'Tag', 'T']])
183 if self.payload_cnt == 5:
184 self.state = 'HEADER'
186 self.data_col_parity = [0, 0, 0, 0, 0, 0]
187 self.col_parity = [0, 0, 0, 0, 0, 0]
188 self.col_parity_pos = []
189 self.all_row_parity_ok = True
191 def manchester_decode(self, pl, pp, pin):
192 bit = self.oldpin ^ self.polarity
193 if pl > self.halfbit_limit:
194 es = int(self.samplenum - pl/2)
195 if self.oldpl > self.halfbit_limit:
196 ss = int(self.oldsamplenum - self.oldpl/2)
198 ss = int(self.oldsamplenum - self.oldpl)
199 self.putbit(bit, ss, es)
200 self.last_bit_pos = int(self.samplenum - pl/2)
202 es = int(self.samplenum)
203 if self.oldpl > self.halfbit_limit:
204 ss = int(self.oldsamplenum - self.oldpl/2)
205 self.putbit(bit, ss, es)
206 self.last_bit_pos = int(self.samplenum)
208 if self.last_bit_pos <= self.oldsamplenum - self.oldpl:
209 ss = int(self.oldsamplenum - self.oldpl)
210 self.putbit(bit, ss, es)
211 self.last_bit_pos = int(self.samplenum)
214 if not self.samplerate:
215 raise SamplerateError('Cannot decode without samplerate.')
217 # Initialize internal state from the very first sample.
220 self.last_samplenum = self.samplenum
221 self.lastlast_samplenum = self.samplenum
222 self.last_edge = self.samplenum
225 self.oldsamplenum = 0
226 self.last_bit_pos = 0
229 # Ignore identical samples, only process edges.
230 (pin,) = self.wait({0: 'e'})
231 pl = self.samplenum - self.oldsamplenum
233 self.manchester_decode(pl, pp, pin)
236 self.oldsamplenum = self.samplenum