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| -rw-r--r-- | decoders/pwm/__init__.py | 25 | ||||
| -rw-r--r-- | decoders/pwm/pd.py | 97 |
2 files changed, 122 insertions, 0 deletions
diff --git a/decoders/pwm/__init__.py b/decoders/pwm/__init__.py new file mode 100644 index 0000000..096e077 --- /dev/null +++ b/decoders/pwm/__init__.py @@ -0,0 +1,25 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2014 Torsten Duwe <duwe@suse.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 +## + +''' +Pulse-width modulation (a.k.a pulse-duration modulation, PDM) decoder. +''' + +from .pd import Decoder diff --git a/decoders/pwm/pd.py b/decoders/pwm/pd.py new file mode 100644 index 0000000..999b496 --- /dev/null +++ b/decoders/pwm/pd.py @@ -0,0 +1,97 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2014 Torsten Duwe <duwe@suse.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 +## + +import sigrokdecode as srd + +class Decoder(srd.Decoder): + api_version = 2 + id = 'pwm' + name = 'PWM' + longname = 'Pulse-width modulation' + desc = 'Analog level encoded in duty cycle percentage.' + license = 'gplv2+' + inputs = ['logic'] + outputs = ['pwm'] + channels = ( + {'id': 'pwm', 'name': 'PWM in', 'desc': 'Modulation pulses'}, + ) + options = ( + {'id': 'new_cycle_edge', 'desc': 'New cycle on which edge', + 'default': 'rising', 'values': ('rising', 'falling')}, + ) + annotations = ( + ('value', 'PWM value'), + ) + binary = ( + ('raw', 'RAW file'), + ) + + def __init__(self, **kwargs): + self.ss = self.es = -1 + self.high = 1 + self.low = 1 + self.lastedge = 0 + self.oldpin = 0 + self.startedge = 0 + self.num_cycles = 0 + + def start(self): + self.out_python = self.register(srd.OUTPUT_PYTHON) + self.out_ann = self.register(srd.OUTPUT_ANN) + self.out_bin = self.register(srd.OUTPUT_BINARY) + self.out_freq = self.register(srd.OUTPUT_META, + meta=(int, 'Frequency', 'PWM base (cycle) frequency')) + self.startedge = 0 + if self.options['new_cycle_edge'] == 'falling': + self.startedge = 1 + + def putx(self, data): + self.put(self.ss, self.es, self.out_ann, data) + + def putp(self, data): + self.put(self.ss, self.es, self.out_python, data) + + def putb(self, data): + self.put(self.num_cycles, self.num_cycles, self.out_bin, data) + + def decode(self, ss, es, data): + for (self.samplenum, pins) in data: + # Ignore identical samples early on (for performance reasons). + if self.oldpin == pins[0]: + continue + + if self.oldpin == 0: # Rising edge. + self.low = self.samplenum - self.lastedge + else: + self.high = self.samplenum - self.lastedge + + if self.oldpin == self.startedge: + self.es = self.samplenum # This interval ends at this edge. + if self.ss >= 0: # Have we completed a hi-lo sequence? + self.putx([0, ["%d%%" % ((100 * self.high) // (self.high + self.low))]]) + self.putb((0, bytes([(256 * self.high) // (self.high + self.low)]))) + self.num_cycles += 1 + else: + # Mid-interval. + # This interval started at the previous edge. + self.ss = self.lastedge + + self.lastedge = self.samplenum + self.oldpin = pins[0] |