diff options
Diffstat (limited to 'decoders')
| -rw-r--r-- | decoders/Makefile.am | 1 | ||||
| -rw-r--r-- | decoders/dcf77.py | 279 |
2 files changed, 280 insertions, 0 deletions
diff --git a/decoders/Makefile.am b/decoders/Makefile.am index 33efdba..8b64f7f 100644 --- a/decoders/Makefile.am +++ b/decoders/Makefile.am @@ -22,6 +22,7 @@ pkgdatadir = $(DECODERS_DIR) # Please keep this list in alphabetical order. dist_pkgdata_DATA = \ + dcf77.py \ ddc.py \ i2c.py \ mx25lxx05d.py \ diff --git a/decoders/dcf77.py b/decoders/dcf77.py new file mode 100644 index 0000000..7002660 --- /dev/null +++ b/decoders/dcf77.py @@ -0,0 +1,279 @@ +## +## 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 + |