diff --git a/libsigrokdecode4DSL/decoders/sdq/__init__.py b/libsigrokdecode4DSL/decoders/sdq/__init__.py new file mode 100644 index 00000000..3fc10438 --- /dev/null +++ b/libsigrokdecode4DSL/decoders/sdq/__init__.py @@ -0,0 +1,28 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2019-2020 Philip Åkesson +## +## 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 . +## + +''' +The SDQ protocol was developed by Texas Instruments, and is used in +devices like battery pack authentication. Apple uses SDQ in MagSafe +and Lightning connectors, as well as some batteries. + +See https://www.ti.com/lit/ds/symlink/bq26100.pdf for details. +''' + +from .pd import Decoder diff --git a/libsigrokdecode4DSL/decoders/sdq/pd.py b/libsigrokdecode4DSL/decoders/sdq/pd.py new file mode 100644 index 00000000..66df4202 --- /dev/null +++ b/libsigrokdecode4DSL/decoders/sdq/pd.py @@ -0,0 +1,131 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2019-2020 Philip Åkesson +## +## 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 . +## + +from common.srdhelper import bitpack +import sigrokdecode as srd + +class SamplerateError(Exception): + pass + +class Pin: + SDQ, = range(1) + +class Ann: + BIT, BYTE, BREAK, = range(3) + +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', (Ann.BIT,)), + ('bytes', 'Bytes', (Ann.BYTE,)), + ('breaks', 'Breaks', (Ann.BREAK,)), + ) + + 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 __init__(self): + self.reset() + + def reset(self): + self.samplerate = None + 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 + + def handle_bit(self, bit): + self.bits.append(bit) + self.putetu([Ann.BIT, [ + 'Bit: {:d}'.format(bit), + '{:d}'.format(bit), + ]]) + + if len(self.bits) == 8: + byte = bitpack(self.bits) + self.putbetu([Ann.BYTE, [ + 'Byte: 0x{:02x}'.format(byte), + '0x{:02x}'.format(byte), + ]]) + self.bits = [] + self.bytepos = 0 + + def handle_break(self): + self.puts([Ann.BREAK, ['Break', 'BR']]) + self.bits = [] + self.startsample = self.samplenum + self.bytepos = 0 + + def decode(self): + if not self.samplerate: + raise SamplerateError('Cannot decode without samplerate.') + self.bit_width = float(self.samplerate) / float(self.options['bitrate']) + self.half_bit_width = self.bit_width / 2.0 + # BREAK if the line is low for longer than this. + break_threshold = self.bit_width * 1.2 + + # Wait until the line is high before inspecting input data. + sdq, = self.wait({Pin.SDQ: 'h'}) + while True: + # Get the length of a low pulse (falling to rising edge). + sdq, = self.wait({Pin.SDQ: 'f'}) + self.startsample = self.samplenum + if self.bytepos == 0: + self.bytepos = self.samplenum + sdq, = self.wait({Pin.SDQ: 'r'}) + + # Check for 0 or 1 data bits, or the BREAK symbol. + delta = self.samplenum - self.startsample + if delta > break_threshold: + self.handle_break() + elif delta > self.half_bit_width: + self.handle_bit(0) + else: + self.handle_bit(1)