2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2012-2014 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 import sigrokdecode as srd
24 # Return the specified BCD number (max. 8 bits) as integer.
26 return (b & 0x0f) + ((b >> 4) * 10)
28 class SamplerateError(Exception):
31 class Decoder(srd.Decoder):
35 longname = 'DCF77 time protocol'
36 desc = 'European longwave time signal (77.5kHz carrier signal).'
41 {'id': 'data', 'name': 'DATA', 'desc': 'DATA line'},
44 ('start-of-minute', 'Start of minute'),
45 ('special-bits', 'Special bits (civil warnings, weather forecast)'),
46 ('call-bit', 'Call bit'),
47 ('summer-time', 'Summer time announcement'),
50 ('leap-second', 'Leap second bit'),
51 ('start-of-time', 'Start of encoded time'),
53 ('minute-parity', 'Minute parity bit'),
55 ('hour-parity', 'Hour parity bit'),
56 ('day', 'Day of month'),
57 ('day-of-week', 'Day of week'),
60 ('date-parity', 'Date parity bit'),
61 ('raw-bits', 'Raw bits'),
62 ('unknown-bits', 'Unknown bits'),
63 ('warnings', 'Human-readable warnings'),
66 ('bits', 'Bits', (17, 18)),
67 ('fields', 'Fields', tuple(range(0, 16 + 1))),
68 ('warnings', 'Warnings', (19,)),
71 def __init__(self, **kwargs):
72 self.samplerate = None
73 self.state = 'WAIT FOR RISING EDGE'
77 self.ss_bit = self.ss_bit_old = self.es_bit = self.ss_block = 0
79 self.bitcount = 0 # Counter for the DCF77 bits (0..58)
80 self.dcf77_bitnumber_is_known = 0
83 self.out_ann = self.register(srd.OUTPUT_ANN)
85 def metadata(self, key, value):
86 if key == srd.SRD_CONF_SAMPLERATE:
87 self.samplerate = value
90 # Annotation for a single DCF77 bit.
91 self.put(self.ss_bit, self.es_bit, self.out_ann, data)
94 # Annotation for a multi-bit DCF77 field.
95 self.put(self.ss_block, self.samplenum, self.out_ann, data)
97 # TODO: Which range to use? Only the 100ms/200ms or full second?
98 def handle_dcf77_bit(self, bit):
101 # Create one annotation for each DCF77 bit (containing the 0/1 value).
102 # Use 'Unknown DCF77 bit x: val' if we're not sure yet which of the
103 # 0..58 bits it is (because we haven't seen a 'new minute' marker yet).
104 # Otherwise, use 'DCF77 bit x: val'.
105 s = 'B' if self.dcf77_bitnumber_is_known else 'Unknown b'
106 ann = 17 if self.dcf77_bitnumber_is_known else 18
107 self.putx([ann, ['%sit %d: %d' % (s, c, bit), '%d' % bit]])
109 # If we're not sure yet which of the 0..58 DCF77 bits we have, return.
110 # We don't want to decode bogus data.
111 if not self.dcf77_bitnumber_is_known:
114 # Collect bits 36-58, we'll need them for a parity check later.
115 if c in range(36, 58 + 1):
116 self.datebits.append(bit)
118 # Output specific "decoded" annotations for the respective DCF77 bits.
120 # Start of minute: DCF bit 0.
122 self.putx([0, ['Start of minute (always 0)',
123 'Start of minute', 'SoM']])
125 self.putx([19, ['Start of minute != 0', 'SoM != 0']])
126 elif c in range(1, 14 + 1):
127 # Special bits (civil warnings, weather forecast): DCF77 bits 1-14.
130 self.ss_block = self.ss_bit
132 self.tmp |= (bit << (c - 1))
134 s = bin(self.tmp)[2:].zfill(14)
135 self.putb([1, ['Special bits: %s' % s, 'SB: %s' % s]])
137 s = '' if (bit == 1) else 'not '
138 self.putx([2, ['Call bit: %sset' % s, 'CB: %sset' % s]])
139 # TODO: Previously this bit indicated use of the backup antenna.
141 s = '' if (bit == 1) else 'not '
142 x = 'yes' if (bit == 1) else 'no'
143 self.putx([3, ['Summer time announcement: %sactive' % s,
144 'Summer time: %sactive' % s,
145 'Summer time: %s' % x, 'ST: %s' % x]])
147 s = '' if (bit == 1) else 'not '
148 x = 'yes' if (bit == 1) else 'no'
149 self.putx([4, ['CEST: %sin effect' % s, 'CEST: %s' % x]])
151 s = '' if (bit == 1) else 'not '
152 x = 'yes' if (bit == 1) else 'no'
153 self.putx([5, ['CET: %sin effect' % s, 'CET: %s' % x]])
155 s = '' if (bit == 1) else 'not '
156 x = 'yes' if (bit == 1) else 'no'
157 self.putx([6, ['Leap second announcement: %sactive' % s,
158 'Leap second: %sactive' % s,
159 'Leap second: %s' % x, 'LS: %s' % x]])
161 # Start of encoded time: DCF bit 20.
163 self.putx([7, ['Start of encoded time (always 1)',
164 'Start of encoded time', 'SoeT']])
166 self.putx([19, ['Start of encoded time != 1', 'SoeT != 1']])
167 elif c in range(21, 27 + 1):
168 # Minutes (0-59): DCF77 bits 21-27 (BCD format).
171 self.ss_block = self.ss_bit
173 self.tmp |= (bit << (c - 21))
175 m = bcd2int(self.tmp)
176 self.putb([8, ['Minutes: %d' % m, 'Min: %d' % m]])
178 # Even parity over minute bits (21-28): DCF77 bit 28.
179 self.tmp |= (bit << (c - 21))
180 parity = bin(self.tmp).count('1')
181 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
182 self.putx([9, ['Minute parity: %s' % s, 'Min parity: %s' % s]])
183 elif c in range(29, 34 + 1):
184 # Hours (0-23): DCF77 bits 29-34 (BCD format).
187 self.ss_block = self.ss_bit
189 self.tmp |= (bit << (c - 29))
191 self.putb([10, ['Hours: %d' % bcd2int(self.tmp)]])
193 # Even parity over hour bits (29-35): DCF77 bit 35.
194 self.tmp |= (bit << (c - 29))
195 parity = bin(self.tmp).count('1')
196 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
197 self.putx([11, ['Hour parity: %s' % s]])
198 elif c in range(36, 41 + 1):
199 # Day of month (1-31): DCF77 bits 36-41 (BCD format).
202 self.ss_block = self.ss_bit
204 self.tmp |= (bit << (c - 36))
206 self.putb([12, ['Day: %d' % bcd2int(self.tmp)]])
207 elif c in range(42, 44 + 1):
208 # Day of week (1-7): DCF77 bits 42-44 (BCD format).
209 # A value of 1 means Monday, 7 means Sunday.
212 self.ss_block = self.ss_bit
214 self.tmp |= (bit << (c - 42))
216 d = bcd2int(self.tmp)
217 dn = calendar.day_name[d - 1] # day_name[0] == Monday
218 self.putb([13, ['Day of week: %d (%s)' % (d, dn),
219 'DoW: %d (%s)' % (d, dn)]])
220 elif c in range(45, 49 + 1):
221 # Month (1-12): DCF77 bits 45-49 (BCD format).
224 self.ss_block = self.ss_bit
226 self.tmp |= (bit << (c - 45))
228 m = bcd2int(self.tmp)
229 mn = calendar.month_name[m] # month_name[1] == January
230 self.putb([14, ['Month: %d (%s)' % (m, mn),
231 'Mon: %d (%s)' % (m, mn)]])
232 elif c in range(50, 57 + 1):
233 # Year (0-99): DCF77 bits 50-57 (BCD format).
236 self.ss_block = self.ss_bit
238 self.tmp |= (bit << (c - 50))
240 self.putb([15, ['Year: %d' % bcd2int(self.tmp)]])
242 # Even parity over date bits (36-58): DCF77 bit 58.
243 parity = self.datebits.count(1)
244 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
245 self.putx([16, ['Date parity: %s' % s, 'DP: %s' % s]])
248 raise Exception('Invalid DCF77 bit: %d' % c)
250 def decode(self, ss, es, data):
251 if not self.samplerate:
252 raise SamplerateError('Cannot decode without samplerate.')
253 for (self.samplenum, pins) in data:
255 # Ignore identical samples early on (for performance reasons).
256 if self.oldpins == pins:
258 self.oldpins, (val,) = pins, pins
260 if self.state == 'WAIT FOR RISING EDGE':
261 # Wait until the next rising edge occurs.
262 if not (self.oldval == 0 and val == 1):
266 # Save the sample number where the DCF77 bit begins.
267 self.ss_bit = self.samplenum
269 # Calculate the length (in ms) between two rising edges.
270 len_edges = self.ss_bit - self.ss_bit_old
271 len_edges_ms = int((len_edges / self.samplerate) * 1000)
273 # The time between two rising edges is usually around 1000ms.
274 # For DCF77 bit 59, there is no rising edge at all, i.e. the
275 # time between DCF77 bit 59 and DCF77 bit 0 (of the next
276 # minute) is around 2000ms. Thus, if we see an edge with a
277 # 2000ms distance to the last one, this edge marks the
278 # beginning of a new minute (and DCF77 bit 0 of that minute).
279 if len_edges_ms in range(1600, 2400 + 1):
281 self.ss_bit_old = self.ss_bit
282 self.dcf77_bitnumber_is_known = 1
284 self.ss_bit_old = self.ss_bit
285 self.state = 'GET BIT'
287 elif self.state == 'GET BIT':
288 # Wait until the next falling edge occurs.
289 if not (self.oldval == 1 and val == 0):
293 # Save the sample number where the DCF77 bit ends.
294 self.es_bit = self.samplenum
296 # Calculate the length (in ms) of the current high period.
297 len_high = self.samplenum - self.ss_bit
298 len_high_ms = int((len_high / self.samplerate) * 1000)
300 # If the high signal was 100ms long, that encodes a 0 bit.
301 # If it was 200ms long, that encodes a 1 bit.
302 if len_high_ms in range(40, 160 + 1):
304 elif len_high_ms in range(161, 260 + 1):
307 bit = -1 # TODO: Error?
309 # There's no bit 59, make sure none is decoded.
310 if bit in (0, 1) and self.bitcount in range(0, 58 + 1):
311 self.handle_dcf77_bit(bit)
314 self.state = 'WAIT FOR RISING EDGE'