--- /dev/null
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2013 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
+##
+
+pkgdatadir = $(DECODERS_DIR)/guess_bitrate
+
+dist_pkgdata_DATA = __init__.py pd.py
+
+CLEANFILES = *.pyc
+
--- /dev/null
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2013 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
+##
+
+'''
+This protocol decoder tries to guess the bitrate / baudrate of the
+communication on the specified probe. Typically this will be used to
+guess / detect the baudrate used in a UART communication snippet, but it
+could also be used to guess bitrates of certain other protocols or buses.
+
+It should be noted that this is nothing more than a simple guess / heuristic,
+and that there are various cases in practice where the detection of the
+bitrate or baudrate will not necessarily have the expected result.
+
+The precision of the estimated bitrate / baudrate will also depend on the
+samplerate used to sample the respective probe. For good results it is
+recommended to use a logic analyzer samplerate that is much higher than
+the expected bitrate/baudrate that might be used on the probe.
+'''
+
+from .pd import *
+
--- /dev/null
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2013 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
+##
+
+# Bitrate / baudrate guessing protocol decoder
+
+import sigrokdecode as srd
+
+class Decoder(srd.Decoder):
+ api_version = 1
+ id = 'guess_bitrate'
+ name = 'Guess bitrate'
+ longname = 'Guess bitrate/baudrate'
+ desc = 'Guess the bitrate/baudrate of a UART (or other) protocol.'
+ license = 'gplv2+'
+ inputs = ['logic']
+ outputs = ['guess_bitrate']
+ probes = [
+ {'id': 'data', 'name': 'Data', 'desc': 'Data line'},
+ ]
+ optional_probes = []
+ options = {}
+ annotations = [
+ ['bitrate', 'Bitrate / baudrate'],
+ ]
+
+ def putx(self, data):
+ self.put(self.ss_edge, self.samplenum, self.out_ann, data)
+
+ def __init__(self, **kwargs):
+ self.olddata = None
+ self.ss_edge = None
+ self.first_transition = True
+ self.bitwidth = None
+
+ def start(self, metadata):
+ self.samplerate = metadata['samplerate']
+ # self.out_proto = self.add(srd.OUTPUT_PROTO, 'guess_bitrate')
+ self.out_ann = self.add(srd.OUTPUT_ANN, 'guess_bitrate')
+
+ def report(self):
+ pass
+
+ def decode(self, ss, es, data):
+ for (self.samplenum, pins) in data:
+
+ data = pins[0]
+
+ # Wait for any transition on the data line.
+ if data == self.olddata:
+ continue
+
+ # Initialize first self.olddata with the first sample value.
+ if self.olddata == None:
+ self.olddata = data
+ continue
+
+ # Get the smallest distance between two transitions
+ # and use that to calculate the bitrate/baudrate.
+ if self.first_transition == True:
+ self.ss_edge = self.samplenum
+ self.first_transition = False
+ else:
+ b = self.samplenum - self.ss_edge
+ if self.bitwidth == None or b < self.bitwidth:
+ self.bitwidth = b
+ bitrate = int(float(self.samplerate) / float(b))
+ self.putx([0, ['%d' % bitrate]])
+ self.ss_edge = self.samplenum
+
+ self.olddata = data
+
projects / libsigrokdecode.git / commitdiff