## ## 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 data 2 of the License, or ## (at your option) any later data. ## ## 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 = ( ('headerbit', 'Header bit'), ('databit', 'Version bit'), ('rowparity', 'Row Parity'), ('databit', 'Data bit'), ('colparity', 'Column Parity'), ('stopbit', 'Stop bit'), ('rowparity_check', 'Row Parity Check'), ) annotation_rows = ( ('bits', 'Bits', (0,)), ('fields', 'Fields', (1, 2, 4, 7)), ('value', 'Value', (3, 5, 6, 8)), ) def __init__(self, **kwargs): 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.first_start = 0 self.first_one = 0 self.state = 'HEADER' self.data = 0 self.data_bits = 0 self.data_start = 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] def metadata(self, key, value): if key == srd.SRD_CONF_SAMPLERATE: self.samplerate = value self.bit_width = (self.samplerate / (int(self.options['coilfreq']))) * int(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 add_bit(self, bit, bit_start, bit_stop): if self.state == 'HEADER': if bit == 1: if self.first_one > 0: self.first_one += 1 if self.first_one == 9: self.put(int(self.first_start), int(bit_stop), 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.first_start = bit_start if bit == 0: self.first_one = 0 return if self.state == 'PAYLOAD': self.payload_cnt += 1 if self.data_bits == 0: self.data_start = bit_start self.data = 0 self.data_parity = 0 self.data_bits += 1 if self.data_bits == 5: self.put(int(self.data_start), int(bit_start), self.out_ann, [2, ['Data', 'Da', 'D']]) self.put(int(bit_start), int(bit_stop), self.out_ann, [4, ['Parity', 'Par', 'Pa', 'P']]) self.put(int(self.data_start), int(bit_start), self.out_ann, [3, [str("%X" % self.data)]]) if self.data_parity == bit: p_string = ['OK', 'O'] else: p_string = ['ERROR', 'ERR', 'ER', 'E'] self.put(int(bit_start), int(bit_stop), self.out_ann, [6, p_string]) 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.data_start = bit_start self.data = 0 self.data_parity = 0 self.data_bits += 1 self.col_parity[self.data_bits] = bit if self.data_bits == 5: p_string = ['ERROR', 'ERR', 'ER', 'E'] if self.data_col_parity[1] == self.col_parity[1]: if self.data_col_parity[2] == self.col_parity[2]: if self.data_col_parity[3] == self.col_parity[3]: if self.data_col_parity[4] == self.col_parity[4]: p_string = ['OK', 'O'] self.put(int(self.data_start), int(bit_start), self.out_ann, [4, ['Column parity', 'Col par', 'CP', 'P']]) self.put(int(bit_start), int(bit_stop), self.out_ann, [4, ['Stop bit', 'St bi', 'SB', 'S']]) self.put(int(self.data_start), int(bit_start), self.out_ann, [6, p_string]) 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] def putbit(self, bit, bit_start, bit_stop): self.put(int(bit_start), int(bit_stop), self.out_ann, [0, [str(bit)]]) self.add_bit(bit, bit_start, bit_stop) def manchester_decode(self, samplenum, pl, pp, pin): bit_start = 0 bit_stop = 0 bit = self.oldpin ^ self.polarity if pl > self.halfbit_limit: samples = samplenum - self.oldsamplenum t = samples / self.samplerate if self.oldpl > self.halfbit_limit: bit_start = int(self.oldsamplenum - self.oldpl/2) bit_stop = int(samplenum - pl/2) self.putbit(bit, bit_start, bit_stop) if self.oldpl <= self.halfbit_limit: bit_start = int(self.oldsamplenum - self.oldpl) bit_stop = int(samplenum - pl/2) self.putbit(bit, bit_start, bit_stop) self.last_bit_pos = int(samplenum - pl/2) if pl < self.halfbit_limit: samples = samplenum - self.oldsamplenum t = samples / self.samplerate if self.oldpl > self.halfbit_limit: bit_start = self.oldsamplenum - self.oldpl/2 bit_stop = int(samplenum) self.putbit(bit, bit_start, bit_stop) self.last_bit_pos = int(samplenum) if self.oldpl <= self.halfbit_limit: if self.last_bit_pos <= self.oldsamplenum - self.oldpl: bit_start = self.oldsamplenum - self.oldpl bit_stop = int(samplenum) self.putbit(bit, bit_start, bit_stop) 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