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
26 # Annotation feed formats
29 # Return the specified BCD number (max. 8 bits) as integer.
31 return (b & 0x0f) + ((b >> 4) * 10)
33 class Decoder(srd.Decoder):
37 longname = 'DCF77 time protocol'
44 {'id': 'data', 'name': 'DATA', 'desc': 'DATA line'},
47 {'id': 'pon', 'name': 'PON', 'desc': 'TODO'},
52 ['ASCII', 'TODO: description'],
55 def __init__(self, **kwargs):
56 self.state = 'WAIT FOR RISING EDGE'
60 self.bit_start_old = 0
61 self.bitcount = 0 # Counter for the DCF77 bits (0..58)
62 self.dcf77_bitnumber_is_known = 0
64 def start(self, metadata):
65 self.samplerate = metadata['samplerate']
66 # self.out_proto = self.add(srd.OUTPUT_PROTO, 'dcf77')
67 self.out_ann = self.add(srd.OUTPUT_ANN, 'dcf77')
72 # TODO: Which range to use? Only the 100ms/200ms or full second?
73 def handle_dcf77_bit(self, bit):
78 # Create one annotation for each DCF77 bit (containing the 0/1 value).
79 # Use 'Unknown DCF77 bit x: val' if we're not sure yet which of the
80 # 0..58 bits it is (because we haven't seen a 'new minute' marker yet).
81 # Otherwise, use 'DCF77 bit x: val'.
82 s = '' if self.dcf77_bitnumber_is_known else 'Unknown '
83 self.put(ss, es, a, [0, ['%sDCF77 bit %d: %d' % (s, c, bit)]])
85 # If we're not sure yet which of the 0..58 DCF77 bits we have, return.
86 # We don't want to decode bogus data.
87 if not self.dcf77_bitnumber_is_known:
90 # Output specific "decoded" annotations for the respective DCF77 bits.
92 # Start of minute: DCF bit 0.
94 self.put(ss, es, a, [0, ['Start of minute (always 0)']])
96 self.put(ss, es, a, [0, ['ERROR: Start of minute != 0']])
97 elif c in range(1, 14 + 1):
98 # Special bits (civil warnings, weather forecast): DCF77 bits 1-14.
102 self.tmp |= (bit << (c - 1))
104 self.put(ss, es, a, [0, ['Special bits: %s' % bin(self.tmp)]])
106 s = '' if (bit == 1) else 'not '
107 self.put(ss, es, a, [0, ['Call bit is %sset' % s]])
108 # TODO: Previously this bit indicated use of the backup antenna.
110 s = '' if (bit == 1) else 'not '
111 self.put(ss, es, a, [0, ['Summer time announcement %sactive' % s]])
113 s = '' if (bit == 1) else 'not '
114 self.put(ss, es, a, [0, ['CEST is %sin effect' % s]])
116 s = '' if (bit == 1) else 'not '
117 self.put(ss, es, a, [0, ['CET is %sin effect' % s]])
119 s = '' if (bit == 1) else 'not '
120 self.put(ss, es, a, [0, ['Leap second announcement %sactive' % s]])
122 # Start of encoded time: DCF bit 20.
124 self.put(ss, es, a, [0, ['Start of encoded time (always 1)']])
127 [0, ['ERROR: Start of encoded time != 1']])
128 elif c in range(21, 27 + 1):
129 # Minutes (0-59): DCF77 bits 21-27 (BCD format).
133 self.tmp |= (bit << (c - 21))
135 self.put(ss, es, a, [0, ['Minutes: %d' % bcd2int(self.tmp)]])
137 # Even parity over minute bits (21-28): DCF77 bit 28.
138 self.tmp |= (bit << (c - 21))
139 parity = bin(self.tmp).count('1')
140 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
141 self.put(ss, es, a, [0, ['Minute parity: %s' % s]])
142 elif c in range(29, 34 + 1):
143 # Hours (0-23): DCF77 bits 29-34 (BCD format).
147 self.tmp |= (bit << (c - 29))
149 self.put(ss, es, a, [0, ['Hours: %d' % bcd2int(self.tmp)]])
151 # Even parity over hour bits (29-35): DCF77 bit 35.
152 self.tmp |= (bit << (c - 29))
153 parity = bin(self.tmp).count('1')
154 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
155 self.put(ss, es, a, [0, ['Hour parity: %s' % s]])
156 elif c in range(36, 41 + 1):
157 # Day of month (1-31): DCF77 bits 36-41 (BCD format).
161 self.tmp |= (bit << (c - 36))
163 self.put(ss, es, a, [0, ['Day: %d' % bcd2int(self.tmp)]])
164 elif c in range(42, 44 + 1):
165 # Day of week (1-7): DCF77 bits 42-44 (BCD format).
166 # A value of 1 means Monday, 7 means Sunday.
170 self.tmp |= (bit << (c - 42))
172 d = bcd2int(self.tmp)
173 dn = calendar.day_name[d - 1] # day_name[0] == Monday
174 self.put(ss, es, a, [0, ['Day of week: %d (%s)' % (d, dn)]])
175 elif c in range(45, 49 + 1):
176 # Month (1-12): DCF77 bits 45-49 (BCD format).
180 self.tmp |= (bit << (c - 45))
182 m = bcd2int(self.tmp)
183 mn = calendar.month_name[m] # month_name[1] == January
184 self.put(ss, es, a, [0, ['Month: %d (%s)' % (m, mn)]])
185 elif c in range(50, 57 + 1):
186 # Year (0-99): DCF77 bits 50-57 (BCD format).
190 self.tmp |= (bit << (c - 50))
192 self.put(ss, es, a, [0, ['Year: %d' % bcd2int(self.tmp)]])
194 # Even parity over date bits (36-58): DCF77 bit 58.
195 self.tmp |= (bit << (c - 50))
196 parity = bin(self.tmp).count('1')
197 s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
198 self.put(ss, es, a, [0, ['Date parity: %s' % s]])
200 raise Exception('Invalid DCF77 bit: %d' % c)
202 def decode(self, ss, es, data):
203 for samplenum, (val) in data: # TODO: Handle optional PON.
205 self.samplenum += 1 # FIXME. Use samplenum. Off-by-one?
207 if self.state == 'WAIT FOR RISING EDGE':
208 # Wait until the next rising edge occurs.
209 if not (self.oldval == 0 and val == 1):
213 # Save the sample number where the DCF77 bit begins.
214 self.bit_start = self.samplenum
216 # Calculate the length (in ms) between two rising edges.
217 len_edges = self.bit_start - self.bit_start_old
218 len_edges_ms = int((len_edges / self.samplerate) * 1000)
220 # The time between two rising edges is usually around 1000ms.
221 # For DCF77 bit 59, there is no rising edge at all, i.e. the
222 # time between DCF77 bit 59 and DCF77 bit 0 (of the next
223 # minute) is around 2000ms. Thus, if we see an edge with a
224 # 2000ms distance to the last one, this edge marks the
225 # beginning of a new minute (and DCF77 bit 0 of that minute).
226 if len_edges_ms in range(1600, 2400 + 1):
227 self.put(ss, es, self.out_ann, [0, ['New minute starts']])
229 self.bit_start_old = self.bit_start
230 self.dcf77_bitnumber_is_known = 1
231 # Don't switch to GET_BIT state this time.
234 self.bit_start_old = self.bit_start
237 elif self.state == GET_BIT:
238 # Wait until the next falling edge occurs.
239 if not (self.oldval == 1 and val == 0):
243 # Calculate the length (in ms) of the current high period.
244 len_high = self.samplenum - self.bit_start
245 len_high_ms = int((len_high / self.samplerate) * 1000)
247 # If the high signal was 100ms long, that encodes a 0 bit.
248 # If it was 200ms long, that encodes a 1 bit.
249 if len_high_ms in range(40, 160 + 1):
251 elif len_high_ms in range(161, 260 + 1):
254 bit = -1 # TODO: Error?
256 # TODO: There's no bit 59, make sure none is decoded.
257 if bit in (0, 1) and self.bitcount in range(0, 58 + 1):
258 self.handle_dcf77_bit(bit)
261 self.state = 'WAIT FOR RISING EDGE'
264 raise Exception('Invalid state: %d' % self.state)