| ## |
| ## This file is part of the libsigrokdecode project. |
| ## |
| ## Copyright (C) 2012 Iztok Jeras <iztok.jeras@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, 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 = 2 |
| 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.ss_block = 0 |
| self.es_block = 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.ss_block, self.es_block, self.out_ann, data) |
| |
| def puty(self, data): |
| # Helper function for most protocol packets. |
| self.put(self.ss_block, self.es_block, 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]]) |
| |
| # Data collector. |
| def onewire_collect(self, length, val, ss, es): |
| # Storing the sample this sequence begins with. |
| if self.bit_cnt == 1: |
| self.ss_block = 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.es_block = 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.ss_block = 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.es_block = 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 |
