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| -rw-r--r-- | decoders/sdq/__init__.py | 24 | ||||
| -rw-r--r-- | decoders/sdq/pd.py | 131 |
2 files changed, 155 insertions, 0 deletions
diff --git a/decoders/sdq/__init__.py b/decoders/sdq/__init__.py new file mode 100644 index 0000000..7087bda --- /dev/null +++ b/decoders/sdq/__init__.py @@ -0,0 +1,24 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2019-2020 Philip Åkesson <philip.akesson@gmail.com> +## +## 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/>. +## + +''' +Texas Instruments SDQ protocol, also used by Apple. +''' + +from .pd import Decoder diff --git a/decoders/sdq/pd.py b/decoders/sdq/pd.py new file mode 100644 index 0000000..80b15ff --- /dev/null +++ b/decoders/sdq/pd.py @@ -0,0 +1,131 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2019-2020 Philip Åkesson <philip.akesson@gmail.com> +## +## 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 + +class SamplerateError(Exception): + pass + +class Decoder(srd.Decoder): + api_version = 3 + id = 'sdq' + name = 'SDQ' + longname = 'Texas Instruments SDQ' + desc = 'Texas Instruments SDQ. The SDQ protocol is also used by Apple.' + license = 'gplv2+' + inputs = ['logic'] + outputs = [] + tags = ['Embedded/industrial'] + channels = ( + {'id': 'sdq', 'name': 'SDQ', 'desc': 'Single wire SDQ data line.'}, + ) + options = ( + {'id': 'bitrate', 'desc': 'Bit rate', 'default': 98425}, + ) + annotations = ( + ('bit', 'Bit'), + ('byte', 'Byte'), + ('break', 'Break'), + ) + annotation_rows = ( + ('bits', 'Bits', (0,)), + ('bytes', 'Bytes', (1,)), + ('breaks', 'Breaks', (2,)), + ) + + def puts(self, data): + self.put(self.startsample, self.samplenum, self.out_ann, data) + + def putetu(self, data): + self.put(self.startsample, self.startsample + int(self.bit_width), self.out_ann, data) + + def putbetu(self, data): + self.put(self.bytepos, self.startsample + int(self.bit_width), self.out_ann, data) + + def bits2num(self, bitlist): + number = 0 + for i in range(len(bitlist)): + number += bitlist[i] * 2**i + return number + + def __init__(self): + self.reset() + + def reset(self): + self.samplerate = None + self.state = 'INIT' + self.startsample = 0 + self.bits = [] + self.bytepos = 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 + self.bit_width = float(self.samplerate) / float(self.options['bitrate']) + self.half_bit_width = self.bit_width / 2.0 + self.break_threshold = self.bit_width * 1.2 # Break if the line is low for longer than this + + def handle_bit(self, bit): + self.bits.append(bit) + self.putetu([0, ['Bit: %d' % bit, '%d' % bit]]) + + if len(self.bits) == 8: + byte = self.bits2num(self.bits) + self.putbetu([1, ['Byte: %#04x' % byte, '%#04x' % byte]]) + self.bits = [] + self.bytepos = 0 + + def handle_break(self): + self.puts([2, ['Break', 'BR']]) + self.bits = [] + self.startsample = self.samplenum + self.bytepos = 0 + + def decode(self): + if not self.samplerate: + raise SamplerateError('Cannot decode without samplerate.') + + while True: + if self.state == 'INIT': + sdq, = self.wait({0: 'h'}) # Wait until the line is high before starting + self.state = 'DATA' + + elif self.state == 'DATA': + sdq, = self.wait({0: 'f'}) # Falling edge + + self.startsample = self.samplenum + if self.bytepos == 0: + self.bytepos = self.samplenum + + sdq, = self.wait({0: 'r'}) # Rising edge + + delta = self.samplenum - self.startsample + if delta > self.break_threshold: + self.state = 'BREAK' + elif delta > self.half_bit_width: + self.handle_bit(0) + else: + self.handle_bit(1) + + elif self.state == 'BREAK': + self.handle_break() + self.state = 'DATA' |