2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2012-2013 Uwe Hermann <uwe@hermann-uwe.de>
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, write to the Free Software
18 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 # DCF77 protocol decoder
23 import sigrokdecode as srd
26 # Return the specified BCD number (max. 8 bits) as integer.
28 return (b & 0x0f) + ((b >> 4) * 10)
30 class Decoder(srd.Decoder):
34 longname = 'DCF77 time protocol'
35 desc = 'European longwave time signal (77.5kHz carrier signal).'
40 {'id': 'data', 'name': 'DATA', 'desc': 'DATA line'},
45 ['start_of_minute', 'Start of minute'],
46 ['special_bits', 'Special bits (civil warnings, weather forecast)'],
47 ['call_bit', 'Call bit'],
48 ['summer_time', 'Summer time announcement'],
51 ['leap_second', 'Leap second bit'],
52 ['start_of_time', 'Start of encoded time'],
54 ['minute_parity', 'Minute parity bit'],
56 ['hour_parity', 'Hour parity bit'],
57 ['day', 'Day of month'],
58 ['day_of_week', 'Day of week'],
61 ['date_parity', 'Date parity bit'],
62 ['raw_bits', 'Raw bits'],
63 ['unknown_bits', 'Unknown bits'],
64 ['warnings', 'Human-readable warnings'],
67 def __init__(self, **kwargs):
68 self.state = 'WAIT FOR RISING EDGE'
72 self.ss_bit = self.ss_bit_old = self.es_bit = self.ss_block = 0
74 self.bitcount = 0 # Counter for the DCF77 bits (0..58)
75 self.dcf77_bitnumber_is_known = 0
77 def start(self, metadata):
78 self.samplerate = metadata['samplerate']
79 # self.out_proto = self.add(srd.OUTPUT_PROTO, 'dcf77')
80 self.out_ann = self.add(srd.OUTPUT_ANN, 'dcf77')
86 # Annotation for a single DCF77 bit.
87 self.put(self.ss_bit, self.es_bit, self.out_ann, data)
90 # Annotation for a multi-bit DCF77 field.
91 self.put(self.ss_block, self.samplenum, self.out_ann, data)
93 # TODO: Which range to use? Only the 100ms/200ms or full second?
94 def handle_dcf77_bit(self, bit):
97 # Create one annotation for each DCF77 bit (containing the 0/1 value).
98 # Use 'Unknown DCF77 bit x: val' if we're not sure yet which of the
99 # 0..58 bits it is (because we haven't seen a 'new minute' marker yet).
100 # Otherwise, use 'DCF77 bit x: val'.
101 s = 'B' if self.dcf77_bitnumber_is_known else 'Unknown b'
102 ann = 17 if self.dcf77_bitnumber_is_known else 18
103 self.putx([ann, ['%sit %d: %d' % (s, c, bit), '%d' % bit]])
105 # If we're not sure yet which of the 0..58 DCF77 bits we have, return.
106 # We don't want to decode bogus data.
107 if not self.dcf77_bitnumber_is_known:
110 # Collect bits 36-58, we'll need them for a parity check later.
111 if c in range(36, 58 + 1):
112 self.datebits.append(bit)
114 # Output specific "decoded" annotations for the respective DCF77 bits.
116 # Start of minute: DCF bit 0.
118 self.putx([0, ['Start of minute (always 0)',
119 'Start of minute', 'SoM']])
121 self.putx([19, ['Start of minute != 0', 'SoM != 0']])
122 elif c in range(1, 14 + 1):
123 # Special bits (civil warnings, weather forecast): DCF77 bits 1-14.
126 self.ss_block = self.ss_bit
128 self.tmp |= (bit << (c - 1))
130 s = bin(self.tmp)[2:].zfill(14)
131 self.putb([1, ['Special bits: %s' % s, 'SB: %s' % s]])
133 s = '' if (bit == 1) else 'not '
134 self.putx([2, ['Call bit: %sset' % s, 'CB: %sset' % s]])
135 # TODO: Previously this bit indicated use of the backup antenna.
137 s = '' if (bit == 1) else 'not '
138 x = 'yes' if (bit == 1) else 'no'
139 self.putx([3, ['Summer time announcement: %sactive' % s,
140 'Summer time: %sactive' % s,
141 'Summer time: %s' % x, 'ST: %s' % x]])
143 s = '' if (bit == 1) else 'not '
144 x = 'yes' if (bit == 1) else 'no'
145 self.putx([4, ['CEST: %sin effect' % s, 'CEST: %s' % x]])
147 s = '' if (bit == 1) else 'not '
148 x = 'yes' if (bit == 1) else 'no'
149 self.putx([5, ['CET: %sin effect' % s, 'CET: %s' % x]])
151 s = '' if (bit == 1) else 'not '
152 x = 'yes' if (bit == 1) else 'no'
153 self.putx([6, ['Leap second announcement: %sactive' % s,
154 'Leap second: %sactive' % s,
155 'Leap second: %s' % x, 'LS: %s' % x]])
157 # Start of encoded time: DCF bit 20.
159 self.putx([7, ['Start of encoded time (always 1)',
160 'Start of encoded time', 'SoeT']])
162 self.putx([19, ['Start of encoded time != 1', 'SoeT != 1']])
163 elif c in range(21, 27 + 1):
164 # Minutes (0-59): DCF77 bits 21-27 (BCD format).
167 self.ss_block = self.ss_bit
169 self.tmp |= (bit << (c - 21))
171 m = bcd2int(self.tmp)
172 self.putb([8, ['Minutes: %d' % m, 'Min: %d' % m]])
174 # Even parity over minute bits (21-28): DCF77 bit 28.
175 self.tmp |= (bit << (c - 21))
176 parity = bin(self.tmp).count('1')
177 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
178 self.putx([9, ['Minute parity: %s' % s, 'Min parity: %s' % s]])
179 elif c in range(29, 34 + 1):
180 # Hours (0-23): DCF77 bits 29-34 (BCD format).
183 self.ss_block = self.ss_bit
185 self.tmp |= (bit << (c - 29))
187 self.putb([10, ['Hours: %d' % bcd2int(self.tmp)]])
189 # Even parity over hour bits (29-35): DCF77 bit 35.
190 self.tmp |= (bit << (c - 29))
191 parity = bin(self.tmp).count('1')
192 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
193 self.putx([11, ['Hour parity: %s' % s]])
194 elif c in range(36, 41 + 1):
195 # Day of month (1-31): DCF77 bits 36-41 (BCD format).
198 self.ss_block = self.ss_bit
200 self.tmp |= (bit << (c - 36))
202 self.putb([12, ['Day: %d' % bcd2int(self.tmp)]])
203 elif c in range(42, 44 + 1):
204 # Day of week (1-7): DCF77 bits 42-44 (BCD format).
205 # A value of 1 means Monday, 7 means Sunday.
208 self.ss_block = self.ss_bit
210 self.tmp |= (bit << (c - 42))
212 d = bcd2int(self.tmp)
213 dn = calendar.day_name[d - 1] # day_name[0] == Monday
214 self.putb([13, ['Day of week: %d (%s)' % (d, dn),
215 'DoW: %d (%s)' % (d, dn)]])
216 elif c in range(45, 49 + 1):
217 # Month (1-12): DCF77 bits 45-49 (BCD format).
220 self.ss_block = self.ss_bit
222 self.tmp |= (bit << (c - 45))
224 m = bcd2int(self.tmp)
225 mn = calendar.month_name[m] # month_name[1] == January
226 self.putx([14, ['Month: %d (%s)' % (m, mn),
227 'Mon: %d (%s)' % (m, mn)]])
228 elif c in range(50, 57 + 1):
229 # Year (0-99): DCF77 bits 50-57 (BCD format).
232 self.ss_block = self.ss_bit
234 self.tmp |= (bit << (c - 50))
236 self.putb([15, ['Year: %d' % bcd2int(self.tmp)]])
238 # Even parity over date bits (36-58): DCF77 bit 58.
239 parity = self.datebits.count(1)
240 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
241 self.putx([16, ['Date parity: %s' % s, 'DP: %s' %s]])
244 raise Exception('Invalid DCF77 bit: %d' % c)
246 def decode(self, ss, es, data):
247 for (self.samplenum, pins) in data:
249 # Ignore identical samples early on (for performance reasons).
250 if self.oldpins == pins:
252 self.oldpins, (val,) = pins, pins
254 if self.state == 'WAIT FOR RISING EDGE':
255 # Wait until the next rising edge occurs.
256 if not (self.oldval == 0 and val == 1):
260 # Save the sample number where the DCF77 bit begins.
261 self.ss_bit = self.samplenum
263 # Calculate the length (in ms) between two rising edges.
264 len_edges = self.ss_bit - self.ss_bit_old
265 len_edges_ms = int((len_edges / self.samplerate) * 1000)
267 # The time between two rising edges is usually around 1000ms.
268 # For DCF77 bit 59, there is no rising edge at all, i.e. the
269 # time between DCF77 bit 59 and DCF77 bit 0 (of the next
270 # minute) is around 2000ms. Thus, if we see an edge with a
271 # 2000ms distance to the last one, this edge marks the
272 # beginning of a new minute (and DCF77 bit 0 of that minute).
273 if len_edges_ms in range(1600, 2400 + 1):
275 self.ss_bit_old = self.ss_bit
276 self.dcf77_bitnumber_is_known = 1
278 self.ss_bit_old = self.ss_bit
279 self.state = 'GET BIT'
281 elif self.state == 'GET BIT':
282 # Wait until the next falling edge occurs.
283 if not (self.oldval == 1 and val == 0):
287 # Save the sample number where the DCF77 bit ends.
288 self.es_bit = self.samplenum
290 # Calculate the length (in ms) of the current high period.
291 len_high = self.samplenum - self.ss_bit
292 len_high_ms = int((len_high / self.samplerate) * 1000)
294 # If the high signal was 100ms long, that encodes a 0 bit.
295 # If it was 200ms long, that encodes a 1 bit.
296 if len_high_ms in range(40, 160 + 1):
298 elif len_high_ms in range(161, 260 + 1):
301 bit = -1 # TODO: Error?
303 # There's no bit 59, make sure none is decoded.
304 if bit in (0, 1) and self.bitcount in range(0, 58 + 1):
305 self.handle_dcf77_bit(bit)
308 self.state = 'WAIT FOR RISING EDGE'
311 raise Exception('Invalid state: %s' % self.state)