mirror of
https://github.com/DreamSourceLab/DSView.git
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136 lines
5.0 KiB
Python
Executable File
136 lines
5.0 KiB
Python
Executable File
##
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## This file is part of the libsigrokdecode project.
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##
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## Copyright (C) 2016 Sean Burford <sburford@google.com>
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##
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## This program is free software; you can redistribute it and/or modify
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## it under the terms of the GNU General Public License as published by
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## the Free Software Foundation; either version 2 of the License, or
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## (at your option) any later version.
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##
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## This program is distributed in the hope that it will be useful,
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## but WITHOUT ANY WARRANTY; without even the implied warranty of
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## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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## GNU General Public License for more details.
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##
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## You should have received a copy of the GNU General Public License
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## along with this program; if not, write to the Free Software
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## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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##
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import sigrokdecode as srd
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class Decoder(srd.Decoder):
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api_version = 2
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id = 'wiegand'
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name = 'Wiegand'
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longname = 'Wiegand interface'
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desc = 'Wiegand interface for electronic entry systems.'
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license = 'gplv2+'
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inputs = ['logic']
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outputs = ['wiegand']
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channels = (
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{'id': 'd0', 'name': 'D0', 'desc': 'Data 0 line'},
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{'id': 'd1', 'name': 'D1', 'desc': 'Data 1 line'},
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)
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options = (
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{'id': 'active', 'desc': 'Data lines active level',
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'default': 'low', 'values': ('low', 'high')},
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{'id': 'bitwidth_ms', 'desc': 'Single bit width in milliseconds',
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'default': 4, 'values': (1, 2, 4, 8, 16, 32)},
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)
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annotations = (
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('bits', 'Bits'),
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('state', 'State'),
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)
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annotation_rows = (
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('bits', 'Binary value', (0,)),
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('state', 'Stream state', (1,)),
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)
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def __init__(self):
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self._samples_per_bit = 10
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self._d0_prev = None
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self._d1_prev = None
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self._state = None
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self.ss_state = None
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self.ss_bit = None
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self.es_bit = None
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self._bit = None
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self._bits = []
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def start(self):
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'Register output types and verify user supplied decoder values.'
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self.out_ann = self.register(srd.OUTPUT_ANN)
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self._active = self.options['active'] == 'high' and 1 or 0
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self._inactive = 1 - self._active
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def metadata(self, key, value):
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'Receive decoder metadata about the data stream.'
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if key == srd.SRD_CONF_SAMPLERATE:
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ms_per_sample = 1000 * (1.0 / value)
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ms_per_bit = float(self.options['bitwidth_ms'])
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self._samples_per_bit = int(max(1, int(ms_per_bit / ms_per_sample)))
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def _update_state(self, state, bit=None):
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'Update state and bit values when they change.'
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if self._bit is not None:
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self._bits.append(self._bit)
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self.put(self.ss_bit, self.samplenum, self.out_ann,
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[0, [str(self._bit)]])
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self._bit = bit
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self.ss_bit = self.samplenum
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if bit is not None:
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# Set a timeout so that the final bit ends.
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self.es_bit = self.samplenum + self._samples_per_bit
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else:
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self.es_bit = None
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if state != self._state:
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ann = None
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if self._state == 'data':
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accum_bits = ''.join(str(x) for x in self._bits)
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ann = [1, ['%d bits %s' % (len(self._bits), accum_bits),
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'%d bits' % len(self._bits)]]
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elif self._state == 'invalid':
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ann = [1, [self._state]]
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if ann:
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self.put(self.ss_state, self.samplenum, self.out_ann, ann)
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self.ss_state = self.samplenum
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self._state = state
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self._bits = []
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def decode(self, ss, es, data):
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for self.samplenum, (d0, d1) in data:
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data.itercnt += 1
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if d0 == self._d0_prev and d1 == self._d1_prev:
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if self.es_bit and self.samplenum >= self.es_bit:
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if (d0, d1) == (self._inactive, self._inactive):
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self._update_state('idle')
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else:
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self._update_state('invalid')
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continue
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if self._state in (None, 'idle', 'data'):
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if (d0, d1) == (self._active, self._inactive):
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self._update_state('data', 0)
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elif (d0, d1) == (self._inactive, self._active):
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self._update_state('data', 1)
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elif (d0, d1) == (self._active, self._active):
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self._update_state('invalid')
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elif self._state == 'invalid':
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# Wait until we see an idle state before leaving invalid.
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# This prevents inverted lines from being misread.
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if (d0, d1) == (self._inactive, self._inactive):
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self._update_state('idle')
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self._d0_prev, self._d1_prev = d0, d1
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def report(self):
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return '%s: %s D0 %d D1 %d (active on %d), %d samples per bit' % (
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self.name, self._state, self._d0_prev, self._d1_prev,
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self._active, self._samples_per_bit)
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