## ## This file is part of the libsigrokdecode project. ## ## Copyright (C) 2012 Iztok Jeras ## ## 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 # Dictionary of ROM commands and their names, next state. command = { 0x33: ['Read ROM' , 'GET ROM' ], 0x0f: ['Conditional read ROM' , 'GET ROM' ], 0xcc: ['Skip ROM' , 'TRANSPORT' ], 0x55: ['Match ROM' , 'GET ROM' ], 0xf0: ['Search ROM' , 'SEARCH ROM'], 0xec: ['Conditional search ROM', 'SEARCH ROM'], 0x3c: ['Overdrive skip ROM' , 'TRANSPORT' ], 0x69: ['Overdrive match ROM' , 'GET ROM' ], } class Decoder(srd.Decoder): api_version = 1 id = 'onewire_network' name = '1-Wire network layer' longname = '1-Wire serial communication bus (network layer)' desc = 'Bidirectional, half-duplex, asynchronous serial bus.' license = 'gplv2+' inputs = ['onewire_link'] outputs = ['onewire_network'] annotations = [ ['text', 'Human-readable text'], ] def __init__(self, **kwargs): self.beg = 0 self.end = 0 self.state = 'COMMAND' self.bit_cnt = 0 self.search = 'P' self.data_p = 0x0 self.data_n = 0x0 self.data = 0x0 self.rom = 0x0000000000000000 def start(self): self.out_python = self.register(srd.OUTPUT_PYTHON) self.out_ann = self.register(srd.OUTPUT_ANN) def putx(self, data): # Helper function for most annotations. self.put(self.beg, self.end, self.out_ann, data) def puty(self, data): # Helper function for most protocol packets. self.put(self.beg, self.end, self.out_python, data) def decode(self, ss, es, data): code, val = data # State machine. if code == 'RESET/PRESENCE': self.search = 'P' self.bit_cnt = 0 self.put(ss, es, self.out_ann, [0, ['Reset/presence: %s' % ('true' if val else 'false')]]) self.put(ss, es, self.out_python, ['RESET/PRESENCE', val]) self.state = 'COMMAND' return # For now we're only interested in 'RESET/PRESENCE' and 'BIT' packets. if code != 'BIT': return if self.state == 'COMMAND': # Receiving and decoding a ROM command. if self.onewire_collect(8, val, ss, es) == 0: return if self.data in command: self.putx([0, ['ROM command: 0x%02x \'%s\'' % (self.data, command[self.data][0])]]) self.state = command[self.data][1] else: self.putx([0, ['ROM command: 0x%02x \'%s\'' % (self.data, 'unrecognized')]]) self.state = 'COMMAND ERROR' elif self.state == 'GET ROM': # A 64 bit device address is selected. # Family code (1 byte) + serial number (6 bytes) + CRC (1 byte) if self.onewire_collect(64, val, ss, es) == 0: return self.rom = self.data & 0xffffffffffffffff self.putx([0, ['ROM: 0x%016x' % self.rom]]) self.puty(['ROM', self.rom]) self.state = 'TRANSPORT' elif self.state == 'SEARCH ROM': # A 64 bit device address is searched for. # Family code (1 byte) + serial number (6 bytes) + CRC (1 byte) if self.onewire_search(64, val, ss, es) == 0: return self.rom = self.data & 0xffffffffffffffff self.putx([0, ['ROM: 0x%016x' % self.rom]]) self.puty(['ROM', self.rom]) self.state = 'TRANSPORT' elif self.state == 'TRANSPORT': # The transport layer is handled in byte sized units. if self.onewire_collect(8, val, ss, es) == 0: return self.putx([0, ['Data: 0x%02x' % self.data]]) self.puty(['DATA', self.data]) elif self.state == 'COMMAND ERROR': # Since the command is not recognized, print raw data. if self.onewire_collect(8, val, ss, es) == 0: return self.putx([0, ['ROM error data: 0x%02x' % self.data]]) else: raise Exception('Invalid state: %s' % self.state) # Data collector. def onewire_collect(self, length, val, ss, es): # Storing the sample this sequence begins with. if self.bit_cnt == 1: self.beg = ss self.data = self.data & ~(1 << self.bit_cnt) | (val << self.bit_cnt) self.bit_cnt += 1 # Storing the sample this sequence ends with. # In case the full length of the sequence is received, return 1. if self.bit_cnt == length: self.end = es self.data = self.data & ((1 << length) - 1) self.bit_cnt = 0 return 1 else: return 0 # Search collector. def onewire_search(self, length, val, ss, es): # Storing the sample this sequence begins with. if (self.bit_cnt == 0) and (self.search == 'P'): self.beg = ss if self.search == 'P': # Master receives an original address bit. self.data_p = self.data_p & ~(1 << self.bit_cnt) | \ (val << self.bit_cnt) self.search = 'N' elif self.search == 'N': # Master receives a complemented address bit. self.data_n = self.data_n & ~(1 << self.bit_cnt) | \ (val << self.bit_cnt) self.search = 'D' elif self.search == 'D': # Master transmits an address bit. self.data = self.data & ~(1 << self.bit_cnt) | (val << self.bit_cnt) self.search = 'P' self.bit_cnt += 1 # Storing the sample this sequence ends with. # In case the full length of the sequence is received, return 1. if self.bit_cnt == length: self.end = es self.data_p = self.data_p & ((1 << length) - 1) self.data_n = self.data_n & ((1 << length) - 1) self.data = self.data & ((1 << length) - 1) self.search = 'P' self.bit_cnt = 0 return 1 else: return 0