## ## This file is part of the libsigrokdecode project. ## ## Copyright (C) 2015 Benjamin Larsson ## ## This program is free software; you can redistribute it and/or modify ## it under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 2 of the License, or ## (at your option) any later version. ## ## This program is distributed in the hope that it will be useful, ## but WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ## GNU General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with this program; if not, write to the Free Software ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA ## import sigrokdecode as srd class SamplerateError(Exception): pass class Decoder(srd.Decoder): api_version = 2 id = 'em4100' name = 'EM4100' longname = 'RFID EM4100' desc = 'EM4100 100-150kHz RFID protocol.' license = 'gplv2+' inputs = ['logic'] outputs = ['em4100'] channels = ( {'id': 'data', 'name': 'Data', 'desc': 'Data line'}, ) options = ( {'id': 'polarity', 'desc': 'Polarity', 'default': 'active-high', 'values': ('active-low', 'active-high')}, {'id': 'datarate' , 'desc': 'Data rate', 'default': 64, 'values': (64, 32, 16)}, # {'id': 'coding', 'desc': 'Bit coding', 'default': 'biphase', # 'values': ('biphase', 'manchester', 'psk')}, {'id': 'coilfreq', 'desc': 'Coil frequency', 'default': 125000}, ) annotations = ( ('bit', 'Bit'), ('header', 'Header'), ('version-customer', 'Version/customer'), ('data', 'Data'), ('rowparity-ok', 'Row parity OK'), ('rowparity-err', 'Row parity error'), ('colparity-ok', 'Column parity OK'), ('colparity-err', 'Column parity error'), ('stopbit', 'Stop bit'), ('tag', 'Tag'), ) annotation_rows = ( ('bits', 'Bits', (0,)), ('fields', 'Fields', (1, 2, 3, 4, 5, 6, 7, 8)), ('tags', 'Tags', (9,)), ) def __init__(self): self.samplerate = None self.oldpin = None self.last_samplenum = None self.lastlast_samplenum = None self.last_edge = 0 self.bit_width = 0 self.halfbit_limit = 0 self.oldpp = 0 self.oldpl = 0 self.oldsamplenum = 0 self.last_bit_pos = 0 self.ss_first = 0 self.first_one = 0 self.state = 'HEADER' self.data = 0 self.data_bits = 0 self.ss_data = 0 self.data_parity = 0 self.payload_cnt = 0 self.data_col_parity = [0, 0, 0, 0, 0, 0] self.col_parity = [0, 0, 0, 0, 0, 0] self.tag = 0 self.all_row_parity_ok = True self.col_parity_pos = [] def metadata(self, key, value): if key == srd.SRD_CONF_SAMPLERATE: self.samplerate = value self.bit_width = (self.samplerate / self.options['coilfreq']) * self.options['datarate'] self.halfbit_limit = self.bit_width/2 + self.bit_width/4 self.polarity = 0 if self.options['polarity'] == 'active-low' else 1 def start(self): self.out_ann = self.register(srd.OUTPUT_ANN) def putbit(self, bit, ss, es): self.put(ss, es, self.out_ann, [0, [str(bit)]]) if self.state == 'HEADER': if bit == 1: if self.first_one > 0: self.first_one += 1 if self.first_one == 9: self.put(self.ss_first, es, self.out_ann, [1, ['Header', 'Head', 'He', 'H']]) self.first_one = 0 self.state = 'PAYLOAD' return if self.first_one == 0: self.first_one = 1 self.ss_first = ss if bit == 0: self.first_one = 0 return if self.state == 'PAYLOAD': self.payload_cnt += 1 if self.data_bits == 0: self.ss_data = ss self.data = 0 self.data_parity = 0 self.data_bits += 1 if self.data_bits == 5: s = 'Version/customer' if self.payload_cnt <= 10 else 'Data' c = 2 if self.payload_cnt <= 10 else 3 self.put(self.ss_data, ss, self.out_ann, [c, [s + ': %X' % self.data, '%X' % self.data]]) s = 'OK' if self.data_parity == bit else 'ERROR' c = 4 if s == 'OK' else 5 if s == 'ERROR': self.all_row_parity_ok = False self.put(ss, es, self.out_ann, [c, ['Row parity: ' + s, 'RP: ' + s, 'RP', 'R']]) self.tag = (self.tag << 4) | self.data self.data_bits = 0 if self.payload_cnt == 50: self.state = 'TRAILER' self.payload_cnt = 0 self.data_parity ^= bit self.data_col_parity[self.data_bits] ^= bit self.data = (self.data << 1) | bit return if self.state == 'TRAILER': self.payload_cnt += 1 if self.data_bits == 0: self.ss_data = ss self.data = 0 self.data_parity = 0 self.data_bits += 1 self.col_parity[self.data_bits] = bit self.col_parity_pos.append([ss, es]) if self.data_bits == 5: self.put(ss, es, self.out_ann, [8, ['Stop bit', 'SB', 'S']]) for i in range(1, 5): s = 'OK' if self.data_col_parity[i] == \ self.col_parity[i] else 'ERROR' c = 6 if s == 'OK' else 7 self.put(self.col_parity_pos[i - 1][0], self.col_parity_pos[i - 1][1], self.out_ann, [c, ['Column parity %d: %s' % (i, s), 'CP%d: %s' % (i, s), 'CP%d' % i, 'C']]) # Emit an annotation for valid-looking tags. all_col_parity_ok = (self.data_col_parity[1:5] == self.col_parity[1:5]) if all_col_parity_ok and self.all_row_parity_ok: self.put(self.ss_first, es, self.out_ann, [9, ['Tag: %010X' % self.tag, 'Tag', 'T']]) self.tag = 0 self.data_bits = 0 if self.payload_cnt == 5: self.state = 'HEADER' self.payload_cnt = 0 self.data_col_parity = [0, 0, 0, 0, 0, 0] self.col_parity = [0, 0, 0, 0, 0, 0] self.col_parity_pos = [] self.all_row_parity_ok = True def manchester_decode(self, samplenum, pl, pp, pin): bit = self.oldpin ^ self.polarity if pl > self.halfbit_limit: es = int(samplenum - pl/2) if self.oldpl > self.halfbit_limit: ss = int(self.oldsamplenum - self.oldpl/2) else: ss = int(self.oldsamplenum - self.oldpl) self.putbit(bit, ss, es) self.last_bit_pos = int(samplenum - pl/2) else: es = int(samplenum) if self.oldpl > self.halfbit_limit: ss = int(self.oldsamplenum - self.oldpl/2) self.putbit(bit, ss, es) self.last_bit_pos = int(samplenum) else: if self.last_bit_pos <= self.oldsamplenum - self.oldpl: ss = int(self.oldsamplenum - self.oldpl) self.putbit(bit, ss, es) self.last_bit_pos = int(samplenum) def decode(self, ss, es, data): if not self.samplerate: raise SamplerateError('Cannot decode without samplerate.') for (samplenum, (pin,)) in data: # Ignore identical samples early on (for performance reasons). if self.oldpin == pin: continue if self.oldpin is None: self.oldpin = pin self.last_samplenum = samplenum self.lastlast_samplenum = samplenum self.last_edge = samplenum self.oldpl = 0 self.oldpp = 0 self.oldsamplenum = 0 self.last_bit_pos = 0 continue if self.oldpin != pin: pl = samplenum - self.oldsamplenum pp = pin self.manchester_decode(samplenum, pl, pp, pin) self.oldpl = pl self.oldpp = pp self.oldsamplenum = samplenum self.oldpin = pin