--- /dev/null
+##
+## This file is part of the sigrok project.
+##
+## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## 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 version 2 of the License, or
+## (at your option) any later version.
+##
+## 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
+##
+
+#
+# DCF77 protocol decoder
+#
+# More information:
+# http://en.wikipedia.org/wiki/DCF77
+#
+
+#
+# Protocol output format:
+# TODO
+#
+
+import sigrokdecode as srd
+import calendar
+
+# States
+WAIT_FOR_RISING_EDGE = 0
+GET_BIT = 1
+
+# Annotation feed formats
+ANN_ASCII = 0
+
+# Return the specified BCD number (max. 8 bits) as integer.
+def bcd2int(b):
+ return (b & 0x0f) + ((b >> 4) * 10)
+
+class Decoder(srd.Decoder):
+ id = 'dcf77'
+ name = 'DCF77'
+ longname = 'TODO.'
+ desc = 'TODO.'
+ longdesc = 'TODO.'
+ author = 'Uwe Hermann'
+ email = 'uwe@hermann-uwe.de'
+ license = 'gplv2+'
+ inputs = ['logic']
+ outputs = ['dcf77']
+ probes = [
+ {'id': 'data', 'name': 'DATA', 'desc': 'DATA line'},
+ ]
+ options = {}
+ annotations = [
+ # ANN_ASCII
+ ['ASCII', 'TODO: description'],
+ ]
+
+ def __init__(self, **kwargs):
+ self.state = WAIT_FOR_RISING_EDGE
+ self.oldval = None
+ self.samplenum = 0
+ self.bit_start = 0
+ self.bit_start_old = 0
+ self.bitcount = 0 # Counter for the DCF77 bits (0..58)
+ self.dcf77_bitnumber_is_known = 0
+
+ def start(self, metadata):
+ self.samplerate = metadata['samplerate']
+ # self.out_proto = self.add(srd.OUTPUT_PROTO, 'dcf77')
+ self.out_ann = self.add(srd.OUTPUT_ANN, 'dcf77')
+
+ def report(self):
+ pass
+
+ # TODO: Which range to use? Only the 100ms/200ms or full second?
+ def handle_dcf77_bit(self, bit):
+ c = self.bitcount
+ a = self.out_ann
+ ss = es = 0 # FIXME
+
+ # Create one annotation for each DCF77 bit (containing the 0/1 value).
+ # Use 'Unknown DCF77 bit x: val' if we're not sure yet which of the
+ # 0..58 bits it is (because we haven't seen a 'new minute' marker yet).
+ # Otherwise, use 'DCF77 bit x: val'.
+ s = '' if self.dcf77_bitnumber_is_known else 'Unknown '
+ self.put(ss, es, a, [0, ['%sDCF77 bit %d: %d' % (s, c, bit)]])
+
+ # If we're not sure yet which of the 0..58 DCF77 bits we have, return.
+ # We don't want to decode bogus data.
+ if not self.dcf77_bitnumber_is_known:
+ return
+
+ # Output specific "decoded" annotations for the respective DCF77 bits.
+ if c == 0:
+ # Start of minute: DCF bit 0.
+ if bit == 0:
+ self.put(ss, es, a, [0, ['Start of minute (always 0)']])
+ else:
+ self.put(ss, es, a, [0, ['ERROR: Start of minute != 0']])
+ elif c in range(1, 14 + 1):
+ # Special bits (civil warnings, weather forecast): DCF77 bits 1-14.
+ if c == 1:
+ self.tmp = bit
+ else:
+ self.tmp |= (bit << (c - 1))
+ if c == 14:
+ self.put(ss, es, a, [0, ['Special bits: %s' % bin(self.tmp)]])
+ elif c == 15:
+ s = '' if (bit == 1) else 'not '
+ self.put(ss, es, a, [0, ['Call bit is %sset' % s]])
+ # TODO: Previously this bit indicated use of the backup antenna.
+ elif c == 16:
+ s = '' if (bit == 1) else 'not '
+ self.put(ss, es, a, [0, ['Summer time announcement %sactive' % s]])
+ elif c == 17:
+ s = '' if (bit == 1) else 'not '
+ self.put(ss, es, a, [0, ['CEST is %sin effect' % s]])
+ elif c == 18:
+ s = '' if (bit == 1) else 'not '
+ self.put(ss, es, a, [0, ['CET is %sin effect' % s]])
+ elif c == 19:
+ s = '' if (bit == 1) else 'not '
+ self.put(ss, es, a, [0, ['Leap second announcement %sactive' % s]])
+ elif c == 20:
+ # Start of encoded time: DCF bit 20.
+ if bit == 1:
+ self.put(ss, es, a, [0, ['Start of encoded time (always 1)']])
+ else:
+ self.put(ss, es, a,
+ [0, ['ERROR: Start of encoded time != 1']])
+ elif c in range(21, 27 + 1):
+ # Minutes (0-59): DCF77 bits 21-27 (BCD format).
+ if c == 21:
+ self.tmp = bit
+ else:
+ self.tmp |= (bit << (c - 21))
+ if c == 27:
+ self.put(ss, es, a, [0, ['Minutes: %d' % bcd2int(self.tmp)]])
+ elif c == 28:
+ # Even parity over minute bits (21-28): DCF77 bit 28.
+ self.tmp |= (bit << (c - 21))
+ parity = bin(self.tmp).count('1')
+ s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
+ self.put(ss, es, a, [0, ['Minute parity: %s' % s]])
+ elif c in range(29, 34 + 1):
+ # Hours (0-23): DCF77 bits 29-34 (BCD format).
+ if c == 29:
+ self.tmp = bit
+ else:
+ self.tmp |= (bit << (c - 29))
+ if c == 34:
+ self.put(ss, es, a, [0, ['Hours: %d' % bcd2int(self.tmp)]])
+ elif c == 35:
+ # Even parity over hour bits (29-35): DCF77 bit 35.
+ self.tmp |= (bit << (c - 29))
+ parity = bin(self.tmp).count('1')
+ s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
+ self.put(ss, es, a, [0, ['Hour parity: %s' % s]])
+ elif c in range(36, 41 + 1):
+ # Day of month (1-31): DCF77 bits 36-41 (BCD format).
+ if c == 36:
+ self.tmp = bit
+ else:
+ self.tmp |= (bit << (c - 36))
+ if c == 41:
+ self.put(ss, es, a, [0, ['Day: %d' % bcd2int(self.tmp)]])
+ elif c in range(42, 44 + 1):
+ # Day of week (1-7): DCF77 bits 42-44 (BCD format).
+ # A value of 1 means Monday, 7 means Sunday.
+ if c == 42:
+ self.tmp = bit
+ else:
+ self.tmp |= (bit << (c - 42))
+ if c == 44:
+ d = bcd2int(self.tmp)
+ dn = calendar.day_name[d - 1] # day_name[0] == Monday
+ self.put(ss, es, a, [0, ['Day of week: %d (%s)' % (d, dn)]])
+ elif c in range(45, 49 + 1):
+ # Month (1-12): DCF77 bits 45-49 (BCD format).
+ if c == 45:
+ self.tmp = bit
+ else:
+ self.tmp |= (bit << (c - 45))
+ if c == 49:
+ m = bcd2int(self.tmp)
+ mn = calendar.month_name[m] # month_name[1] == January
+ self.put(ss, es, a, [0, ['Month: %d (%s)' % (m, mn)]])
+ elif c in range(50, 57 + 1):
+ # Year (0-99): DCF77 bits 50-57 (BCD format).
+ if c == 50:
+ self.tmp = bit
+ else:
+ self.tmp |= (bit << (c - 50))
+ if c == 57:
+ self.put(ss, es, a, [0, ['Year: %d' % bcd2int(self.tmp)]])
+ elif c == 58:
+ # Even parity over date bits (36-58): DCF77 bit 58.
+ self.tmp |= (bit << (c - 50))
+ parity = bin(self.tmp).count('1')
+ s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
+ self.put(ss, es, a, [0, ['Date parity: %s' % s]])
+ else:
+ raise Exception('Invalid DCF77 bit: %d' % c)
+
+ def decode(self, ss, es, data):
+ for samplenum, (pon, val) in data: # FIXME
+
+ self.samplenum += 1 # FIXME. Use samplenum. Off-by-one?
+
+ if self.state == WAIT_FOR_RISING_EDGE:
+ # Wait until the next rising edge occurs.
+ if not (self.oldval == 0 and val == 1):
+ self.oldval = val
+ continue
+
+ # Save the sample number where the DCF77 bit begins.
+ self.bit_start = self.samplenum
+
+ # Calculate the length (in ms) between two rising edges.
+ len_edges = self.bit_start - self.bit_start_old
+ len_edges_ms = int((len_edges / self.samplerate) * 1000)
+
+ # The time between two rising edges is usually around 1000ms.
+ # For DCF77 bit 59, there is no rising edge at all, i.e. the
+ # time between DCF77 bit 59 and DCF77 bit 0 (of the next
+ # minute) is around 2000ms. Thus, if we see an edge with a
+ # 2000ms distance to the last one, this edge marks the
+ # beginning of a new minute (and DCF77 bit 0 of that minute).
+ if len_edges_ms in range(1600, 2400 + 1):
+ self.put(ss, es, self.out_ann, [0, ['New minute starts']])
+ self.bitcount = 0
+ self.bit_start_old = self.bit_start
+ self.dcf77_bitnumber_is_known = 1
+ # Don't switch to GET_BIT state this time.
+ continue
+
+ self.bit_start_old = self.bit_start
+ self.state = GET_BIT
+
+ elif self.state == GET_BIT:
+ # Wait until the next falling edge occurs.
+ if not (self.oldval == 1 and val == 0):
+ self.oldval = val
+ continue
+
+ # Calculate the length (in ms) of the current high period.
+ len_high = self.samplenum - self.bit_start
+ len_high_ms = int((len_high / self.samplerate) * 1000)
+
+ # If the high signal was 100ms long, that encodes a 0 bit.
+ # If it was 200ms long, that encodes a 1 bit.
+ if len_high_ms in range(40, 160 + 1):
+ bit = 0
+ elif len_high_ms in range(161, 260 + 1):
+ bit = 1
+ else:
+ bit = -1 # TODO: Error?
+
+ # TODO: There's no bit 59, make sure none is decoded.
+ if bit in (0, 1) and self.bitcount in range(0, 58 + 1):
+ self.handle_dcf77_bit(bit)
+ self.bitcount += 1
+
+ self.state = WAIT_FOR_RISING_EDGE
+
+ else:
+ raise Exception('Invalid state: %s' % self.state)
+
+ self.oldval = val
+
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