## ## This file is part of the sigrok project. ## ## Copyright (C) 2012 Uwe Hermann ## ## 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): api_version = 1 id = 'dcf77' name = 'DCF77' longname = 'DCF77 time protocol' desc = 'TODO.' longdesc = 'TODO.' license = 'gplv2+' inputs = ['logic'] outputs = ['dcf77'] probes = [ {'id': 'data', 'name': 'DATA', 'desc': 'DATA line'}, ] optional_probes = [ {'id': 'pon', 'name': 'PON', 'desc': 'TODO'}, ] 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, (val) in data: # TODO: Handle optional PON. 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: %d' % self.state) self.oldval = val