/usr/share/libsigrokdecode/decoders/dcf77/pd.py is in libsigrokdecode4 0.5.0-4.
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## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2012-2016 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, see <http://www.gnu.org/licenses/>.
##
import sigrokdecode as srd
import calendar
from common.srdhelper import bcd2int
class SamplerateError(Exception):
pass
class Decoder(srd.Decoder):
api_version = 3
id = 'dcf77'
name = 'DCF77'
longname = 'DCF77 time protocol'
desc = 'European longwave time signal (77.5kHz carrier signal).'
license = 'gplv2+'
inputs = ['logic']
outputs = ['dcf77']
channels = (
{'id': 'data', 'name': 'DATA', 'desc': 'DATA line'},
)
annotations = (
('start-of-minute', 'Start of minute'),
('special-bits', 'Special bits (civil warnings, weather forecast)'),
('call-bit', 'Call bit'),
('summer-time', 'Summer time announcement'),
('cest', 'CEST bit'),
('cet', 'CET bit'),
('leap-second', 'Leap second bit'),
('start-of-time', 'Start of encoded time'),
('minute', 'Minute'),
('minute-parity', 'Minute parity bit'),
('hour', 'Hour'),
('hour-parity', 'Hour parity bit'),
('day', 'Day of month'),
('day-of-week', 'Day of week'),
('month', 'Month'),
('year', 'Year'),
('date-parity', 'Date parity bit'),
('raw-bits', 'Raw bits'),
('unknown-bits', 'Unknown bits'),
('warnings', 'Human-readable warnings'),
)
annotation_rows = (
('bits', 'Bits', (17, 18)),
('fields', 'Fields', tuple(range(0, 16 + 1))),
('warnings', 'Warnings', (19,)),
)
def __init__(self):
self.samplerate = None
self.state = 'WAIT FOR RISING EDGE'
self.ss_bit = self.ss_bit_old = self.es_bit = self.ss_block = 0
self.datebits = []
self.bitcount = 0 # Counter for the DCF77 bits (0..58)
self.dcf77_bitnumber_is_known = 0
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
def metadata(self, key, value):
if key == srd.SRD_CONF_SAMPLERATE:
self.samplerate = value
def putx(self, data):
# Annotation for a single DCF77 bit.
self.put(self.ss_bit, self.es_bit, self.out_ann, data)
def putb(self, data):
# Annotation for a multi-bit DCF77 field.
self.put(self.ss_block, self.samplenum, self.out_ann, data)
# TODO: Which range to use? Only the 100ms/200ms or full second?
def handle_dcf77_bit(self, bit):
c = self.bitcount
# 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 = 'B' if self.dcf77_bitnumber_is_known else 'Unknown b'
ann = 17 if self.dcf77_bitnumber_is_known else 18
self.putx([ann, ['%sit %d: %d' % (s, c, bit), '%d' % 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
# Collect bits 36-58, we'll need them for a parity check later.
if c in range(36, 58 + 1):
self.datebits.append(bit)
# Output specific "decoded" annotations for the respective DCF77 bits.
if c == 0:
# Start of minute: DCF bit 0.
if bit == 0:
self.putx([0, ['Start of minute (always 0)',
'Start of minute', 'SoM']])
else:
self.putx([19, ['Start of minute != 0', 'SoM != 0']])
elif c in range(1, 14 + 1):
# Special bits (civil warnings, weather forecast): DCF77 bits 1-14.
if c == 1:
self.tmp = bit
self.ss_block = self.ss_bit
else:
self.tmp |= (bit << (c - 1))
if c == 14:
s = bin(self.tmp)[2:].zfill(14)
self.putb([1, ['Special bits: %s' % s, 'SB: %s' % s]])
elif c == 15:
s = '' if (bit == 1) else 'not '
self.putx([2, ['Call bit: %sset' % s, 'CB: %sset' % s]])
# TODO: Previously this bit indicated use of the backup antenna.
elif c == 16:
s = '' if (bit == 1) else 'not '
x = 'yes' if (bit == 1) else 'no'
self.putx([3, ['Summer time announcement: %sactive' % s,
'Summer time: %sactive' % s,
'Summer time: %s' % x, 'ST: %s' % x]])
elif c == 17:
s = '' if (bit == 1) else 'not '
x = 'yes' if (bit == 1) else 'no'
self.putx([4, ['CEST: %sin effect' % s, 'CEST: %s' % x]])
elif c == 18:
s = '' if (bit == 1) else 'not '
x = 'yes' if (bit == 1) else 'no'
self.putx([5, ['CET: %sin effect' % s, 'CET: %s' % x]])
elif c == 19:
s = '' if (bit == 1) else 'not '
x = 'yes' if (bit == 1) else 'no'
self.putx([6, ['Leap second announcement: %sactive' % s,
'Leap second: %sactive' % s,
'Leap second: %s' % x, 'LS: %s' % x]])
elif c == 20:
# Start of encoded time: DCF bit 20.
if bit == 1:
self.putx([7, ['Start of encoded time (always 1)',
'Start of encoded time', 'SoeT']])
else:
self.putx([19, ['Start of encoded time != 1', 'SoeT != 1']])
elif c in range(21, 27 + 1):
# Minutes (0-59): DCF77 bits 21-27 (BCD format).
if c == 21:
self.tmp = bit
self.ss_block = self.ss_bit
else:
self.tmp |= (bit << (c - 21))
if c == 27:
m = bcd2int(self.tmp)
self.putb([8, ['Minutes: %d' % m, 'Min: %d' % m]])
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.putx([9, ['Minute parity: %s' % s, 'Min 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
self.ss_block = self.ss_bit
else:
self.tmp |= (bit << (c - 29))
if c == 34:
self.putb([10, ['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.putx([11, ['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
self.ss_block = self.ss_bit
else:
self.tmp |= (bit << (c - 36))
if c == 41:
self.putb([12, ['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
self.ss_block = self.ss_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.putb([13, ['Day of week: %d (%s)' % (d, dn),
'DoW: %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
self.ss_block = self.ss_bit
else:
self.tmp |= (bit << (c - 45))
if c == 49:
m = bcd2int(self.tmp)
mn = calendar.month_name[m] # month_name[1] == January
self.putb([14, ['Month: %d (%s)' % (m, mn),
'Mon: %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
self.ss_block = self.ss_bit
else:
self.tmp |= (bit << (c - 50))
if c == 57:
self.putb([15, ['Year: %d' % bcd2int(self.tmp)]])
elif c == 58:
# Even parity over date bits (36-58): DCF77 bit 58.
parity = self.datebits.count(1)
s = 'OK' if ((parity % 2) == 0) else 'INVALID!'
self.putx([16, ['Date parity: %s' % s, 'DP: %s' % s]])
self.datebits = []
else:
raise Exception('Invalid DCF77 bit: %d' % c)
def decode(self):
if not self.samplerate:
raise SamplerateError('Cannot decode without samplerate.')
while True:
if self.state == 'WAIT FOR RISING EDGE':
# Wait until the next rising edge occurs.
self.wait({0: 'r'})
# Save the sample number where the DCF77 bit begins.
self.ss_bit = self.samplenum
# Calculate the length (in ms) between two rising edges.
len_edges = self.ss_bit - self.ss_bit_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.bitcount = 0
self.ss_bit_old = self.ss_bit
self.dcf77_bitnumber_is_known = 1
self.ss_bit_old = self.ss_bit
self.state = 'GET BIT'
elif self.state == 'GET BIT':
# Wait until the next falling edge occurs.
self.wait({0: 'f'})
# Save the sample number where the DCF77 bit ends.
self.es_bit = self.samplenum
# Calculate the length (in ms) of the current high period.
len_high = self.samplenum - self.ss_bit
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?
# 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'
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