2 ## This file is part of the sigrok project.
4 ## Copyright (C) 2012 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
27 WAIT_FOR_RISING_EDGE = 0
30 # Annotation feed formats
33 # Return the specified BCD number (max. 8 bits) as integer.
35 return (b & 0x0f) + ((b >> 4) * 10)
37 class Decoder(srd.Decoder):
41 longname = 'DCF77 time protocol'
48 {'id': 'data', 'name': 'DATA', 'desc': 'DATA line'},
51 {'id': 'pon', 'name': 'PON', 'desc': 'TODO'},
56 ['ASCII', 'TODO: description'],
59 def __init__(self, **kwargs):
60 self.state = WAIT_FOR_RISING_EDGE
64 self.bit_start_old = 0
65 self.bitcount = 0 # Counter for the DCF77 bits (0..58)
66 self.dcf77_bitnumber_is_known = 0
68 def start(self, metadata):
69 self.samplerate = metadata['samplerate']
70 # self.out_proto = self.add(srd.OUTPUT_PROTO, 'dcf77')
71 self.out_ann = self.add(srd.OUTPUT_ANN, 'dcf77')
76 # TODO: Which range to use? Only the 100ms/200ms or full second?
77 def handle_dcf77_bit(self, bit):
82 # Create one annotation for each DCF77 bit (containing the 0/1 value).
83 # Use 'Unknown DCF77 bit x: val' if we're not sure yet which of the
84 # 0..58 bits it is (because we haven't seen a 'new minute' marker yet).
85 # Otherwise, use 'DCF77 bit x: val'.
86 s = '' if self.dcf77_bitnumber_is_known else 'Unknown '
87 self.put(ss, es, a, [0, ['%sDCF77 bit %d: %d' % (s, c, bit)]])
89 # If we're not sure yet which of the 0..58 DCF77 bits we have, return.
90 # We don't want to decode bogus data.
91 if not self.dcf77_bitnumber_is_known:
94 # Output specific "decoded" annotations for the respective DCF77 bits.
96 # Start of minute: DCF bit 0.
98 self.put(ss, es, a, [0, ['Start of minute (always 0)']])
100 self.put(ss, es, a, [0, ['ERROR: Start of minute != 0']])
101 elif c in range(1, 14 + 1):
102 # Special bits (civil warnings, weather forecast): DCF77 bits 1-14.
106 self.tmp |= (bit << (c - 1))
108 self.put(ss, es, a, [0, ['Special bits: %s' % bin(self.tmp)]])
110 s = '' if (bit == 1) else 'not '
111 self.put(ss, es, a, [0, ['Call bit is %sset' % s]])
112 # TODO: Previously this bit indicated use of the backup antenna.
114 s = '' if (bit == 1) else 'not '
115 self.put(ss, es, a, [0, ['Summer time announcement %sactive' % s]])
117 s = '' if (bit == 1) else 'not '
118 self.put(ss, es, a, [0, ['CEST is %sin effect' % s]])
120 s = '' if (bit == 1) else 'not '
121 self.put(ss, es, a, [0, ['CET is %sin effect' % s]])
123 s = '' if (bit == 1) else 'not '
124 self.put(ss, es, a, [0, ['Leap second announcement %sactive' % s]])
126 # Start of encoded time: DCF bit 20.
128 self.put(ss, es, a, [0, ['Start of encoded time (always 1)']])
131 [0, ['ERROR: Start of encoded time != 1']])
132 elif c in range(21, 27 + 1):
133 # Minutes (0-59): DCF77 bits 21-27 (BCD format).
137 self.tmp |= (bit << (c - 21))
139 self.put(ss, es, a, [0, ['Minutes: %d' % bcd2int(self.tmp)]])
141 # Even parity over minute bits (21-28): DCF77 bit 28.
142 self.tmp |= (bit << (c - 21))
143 parity = bin(self.tmp).count('1')
144 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
145 self.put(ss, es, a, [0, ['Minute parity: %s' % s]])
146 elif c in range(29, 34 + 1):
147 # Hours (0-23): DCF77 bits 29-34 (BCD format).
151 self.tmp |= (bit << (c - 29))
153 self.put(ss, es, a, [0, ['Hours: %d' % bcd2int(self.tmp)]])
155 # Even parity over hour bits (29-35): DCF77 bit 35.
156 self.tmp |= (bit << (c - 29))
157 parity = bin(self.tmp).count('1')
158 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
159 self.put(ss, es, a, [0, ['Hour parity: %s' % s]])
160 elif c in range(36, 41 + 1):
161 # Day of month (1-31): DCF77 bits 36-41 (BCD format).
165 self.tmp |= (bit << (c - 36))
167 self.put(ss, es, a, [0, ['Day: %d' % bcd2int(self.tmp)]])
168 elif c in range(42, 44 + 1):
169 # Day of week (1-7): DCF77 bits 42-44 (BCD format).
170 # A value of 1 means Monday, 7 means Sunday.
174 self.tmp |= (bit << (c - 42))
176 d = bcd2int(self.tmp)
177 dn = calendar.day_name[d - 1] # day_name[0] == Monday
178 self.put(ss, es, a, [0, ['Day of week: %d (%s)' % (d, dn)]])
179 elif c in range(45, 49 + 1):
180 # Month (1-12): DCF77 bits 45-49 (BCD format).
184 self.tmp |= (bit << (c - 45))
186 m = bcd2int(self.tmp)
187 mn = calendar.month_name[m] # month_name[1] == January
188 self.put(ss, es, a, [0, ['Month: %d (%s)' % (m, mn)]])
189 elif c in range(50, 57 + 1):
190 # Year (0-99): DCF77 bits 50-57 (BCD format).
194 self.tmp |= (bit << (c - 50))
196 self.put(ss, es, a, [0, ['Year: %d' % bcd2int(self.tmp)]])
198 # Even parity over date bits (36-58): DCF77 bit 58.
199 self.tmp |= (bit << (c - 50))
200 parity = bin(self.tmp).count('1')
201 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
202 self.put(ss, es, a, [0, ['Date parity: %s' % s]])
204 raise Exception('Invalid DCF77 bit: %d' % c)
206 def decode(self, ss, es, data):
207 for samplenum, (val) in data: # TODO: Handle optional PON.
209 self.samplenum += 1 # FIXME. Use samplenum. Off-by-one?
211 if self.state == WAIT_FOR_RISING_EDGE:
212 # Wait until the next rising edge occurs.
213 if not (self.oldval == 0 and val == 1):
217 # Save the sample number where the DCF77 bit begins.
218 self.bit_start = self.samplenum
220 # Calculate the length (in ms) between two rising edges.
221 len_edges = self.bit_start - self.bit_start_old
222 len_edges_ms = int((len_edges / self.samplerate) * 1000)
224 # The time between two rising edges is usually around 1000ms.
225 # For DCF77 bit 59, there is no rising edge at all, i.e. the
226 # time between DCF77 bit 59 and DCF77 bit 0 (of the next
227 # minute) is around 2000ms. Thus, if we see an edge with a
228 # 2000ms distance to the last one, this edge marks the
229 # beginning of a new minute (and DCF77 bit 0 of that minute).
230 if len_edges_ms in range(1600, 2400 + 1):
231 self.put(ss, es, self.out_ann, [0, ['New minute starts']])
233 self.bit_start_old = self.bit_start
234 self.dcf77_bitnumber_is_known = 1
235 # Don't switch to GET_BIT state this time.
238 self.bit_start_old = self.bit_start
241 elif self.state == GET_BIT:
242 # Wait until the next falling edge occurs.
243 if not (self.oldval == 1 and val == 0):
247 # Calculate the length (in ms) of the current high period.
248 len_high = self.samplenum - self.bit_start
249 len_high_ms = int((len_high / self.samplerate) * 1000)
251 # If the high signal was 100ms long, that encodes a 0 bit.
252 # If it was 200ms long, that encodes a 1 bit.
253 if len_high_ms in range(40, 160 + 1):
255 elif len_high_ms in range(161, 260 + 1):
258 bit = -1 # TODO: Error?
260 # TODO: There's no bit 59, make sure none is decoded.
261 if bit in (0, 1) and self.bitcount in range(0, 58 + 1):
262 self.handle_dcf77_bit(bit)
265 self.state = WAIT_FOR_RISING_EDGE
268 raise Exception('Invalid state: %d' % self.state)