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some fixex to the link layer, not final
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1##
2## This file is part of the sigrok project.
3##
4## Copyright (C) 2011-2012 Uwe Hermann <uwe@hermann-uwe.de>
5##
6## This program is free software; you can redistribute it and/or modify
7## it under the terms of the GNU General Public License as published by
8## the Free Software Foundation; either version 2 of the License, or
9## (at your option) any later version.
10##
11## This program is distributed in the hope that it will be useful,
12## but WITHOUT ANY WARRANTY; without even the implied warranty of
13## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14## GNU General Public License for more details.
15##
16## You should have received a copy of the GNU General Public License
17## along with this program; if not, write to the Free Software
18## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19##
20
21# 1-Wire protocol decoder
22
23import sigrokdecode as srd
24
25# Annotation feed formats
26ANN_ASCII = 0
27ANN_DEC = 1
28ANN_HEX = 2
29ANN_OCT = 3
30ANN_BITS = 4
31
32class Decoder(srd.Decoder):
33 api_version = 1
34 id = 'onewire'
35 name = '1-Wire'
36 longname = ''
37 desc = '1-Wire bus and MicroLan'
38 license = 'gplv2+'
39 inputs = ['logic']
40 outputs = ['onewire']
41 probes = [
42 {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire bus'},
43 ]
44 optional_probes = [
45 {'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power'},
46 ]
47 options = {
48 'overdrive': ['Overdrive', 0],
49 }
50 annotations = [
51 ['ASCII', 'Data bytes as ASCII characters'],
52 ['Decimal', 'Databytes as decimal, integer values'],
53 ['Hex', 'Data bytes in hex format'],
54 ['Octal', 'Data bytes as octal numbers'],
55 ['Bits', 'Data bytes in bit notation (sequence of 0/1 digits)'],
56 ]
57
58 def __init__(self, **kwargs):
59 # Common variables
60 self.samplenum = 0
61 # Link layer variables
62 self.lnk_state = 'WAIT FOR FALLING EDGE'
63 self.lnk_event = 'NONE'
64 self.lnk_fall = 0
65 self.lnk_present = 0
66 self.lnk_bit = 0
67 # Network layer variables
68 self.net_state = 'WAIT FOR COMMAND'
69 self.net_event = 'NONE'
70 self.net_cnt = 0
71 self.net_cmd = 0
72 # Transport layer variables
73 self.trn_state = 'WAIT FOR EVENT'
74 self.trn_event = 'NONE'
75
76 def start(self, metadata):
77 self.samplerate = metadata['samplerate']
78 self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire')
79 self.out_ann = self.add(srd.OUTPUT_ANN , 'onewire')
80
81 # The width of the 1-Wire time base (30us) in number of samples.
82 # TODO: optimize this value
83 self.time_base = float(self.samplerate) * float(0.000030)
84 print ("DEBUG: samplerate = %d, time_base = %d" % (self.samplerate, self.time_base))
85
86 def report(self):
87 pass
88
89 def decode(self, ss, es, data):
90 for (self.samplenum, (owr, pwr)) in data:
91# print ("DEBUG: sample = %d, owr = %d, pwr = %d, lnk_fall = %d, lnk_state = %s" % (self.samplenum, owr, pwr, self.lnk_fall, self.lnk_state))
92
93 # Data link layer
94
95 # Clear events.
96 self.lnk_event = "NONE"
97 # State machine.
98 if self.lnk_state == 'WAIT FOR FALLING EDGE':
99 # The start of a cycle is a falling edge.
100 if (owr == 0):
101 # Save the sample number for the falling edge.
102 self.lnk_fall = self.samplenum
103 # Go to waiting for sample time
104 self.lnk_state = 'WAIT FOR DATA SAMPLE'
105 self.put(self.lnk_fall, self.samplenum, self.out_ann,
106 [ANN_DEC, ['LNK: NEGEDGE: ']])
107 print ("DEBUG: NEGEDGE t0=%d t+=%d" % (self.lnk_fall, self.samplenum))
108 elif self.lnk_state == 'WAIT FOR DATA SAMPLE':
109 # Data should be sample one 'time unit' after a falling edge
110 if (self.samplenum - self.lnk_fall == 1*self.time_base):
111 self.lnk_bit = owr & 0x1
112 self.lnk_event = "DATA BIT"
113 if (self.lnk_bit) : self.lnk_state = 'WAIT FOR FALLING EDGE'
114 else : self.lnk_state = 'WAIT FOR RISING EDGE'
115 self.put(self.lnk_fall, self.samplenum, self.out_ann,
116 [ANN_DEC, ['LNK: BIT: ' + str(self.lnk_bit)]])
117 print ("DEBUG: BIT=%d t0=%d t+=%d" % (self.lnk_bit, self.lnk_fall, self.samplenum))
118 elif self.lnk_state == 'WAIT FOR RISING EDGE':
119 # The end of a cycle is a rising edge.
120 if (owr == 1):
121 # A reset cycle is longer than 8T.
122 if (self.samplenum - self.lnk_fall > 8*self.time_base):
123 # Save the sample number for the falling edge.
124 self.lnk_rise = self.samplenum
125 # Send a reset event to the next protocol layer.
126 self.lnk_event = "RESET"
127 self.lnk_state = "WAIT FOR PRESENCE DETECT"
128 self.put(self.lnk_fall, self.samplenum, self.out_proto,
129 ['RESET'])
130 self.put(self.lnk_fall, self.samplenum, self.out_ann,
131 [ANN_DEC, ['LNK: RESET: ']])
132 print ("DEBUG: RESET t0=%d t+=%d" % (self.lnk_fall, self.samplenum))
133 # Reset the timer.
134 self.lnk_fall = self.samplenum
135 # Otherwise this is assumed to be a data bit.
136 else :
137 self.lnk_state = "WAIT FOR FALLING EDGE"
138 elif self.lnk_state == 'WAIT FOR PRESENCE DETECT':
139 # Data should be sample one 'time unit' after a falling edge
140 if (self.samplenum - self.lnk_rise == 2.5*self.time_base):
141 self.lnk_present = owr & 0x1
142 #self.lnk_event = "PRESENCE DETECT"
143 if (self.lnk_bit) : self.lnk_state = 'WAIT FOR FALLING EDGE'
144 else : self.lnk_state = 'WAIT FOR RISING EDGE'
145 self.put(self.lnk_fall, self.samplenum, self.out_ann,
146 [ANN_DEC, ['LNK: PRESENCE: ' + str(self.lnk_present)]])
147 print ("DEBUG: PRESENCE=%d t0=%d t+=%d" % (self.lnk_present, self.lnk_fall, self.samplenum))
148 else:
149 raise Exception('Invalid lnk_state: %d' % self.lnk_state)
150
151 # Network layer
152
153 # Clear events.
154 self.net_event = "RESET"
155 # State machine.
156 if (self.lnk_event == "RESET"):
157 self.net_state = "WAIT FOR COMMAND"
158 self.net_cnt = 0
159 self.net_cmd = 0
160 elif (self.lnk_event == "DATA BIT"):
161 if (self.net_state == "WAIT FOR COMMAND"):
162 self.net_cnt = self.net_cnt + 1
163 self.net_cmd = (self.net_cmd << 1) & self.lnk_bit
164 if (self.net_cnt == 8):
165 self.put(self.lnk_fall, self.samplenum,
166 self.out_proto, ['LNK: COMMAND', self.net_cmd])
167 self.put(self.lnk_fall, self.samplenum, self.out_ann,
168 [ANN_DEC, ['LNK: COMMAND: ' + self.net_cmd]])
169 if (self.net_cmd == 0x33):
170 # READ ROM
171 break
172 elif (self.net_cmd == 0x0f):
173 # READ ROM
174 break
175 elif (self.net_cmd == 0xcc):
176 # SKIP ROM
177 break
178 elif (self.net_cmd == 0x55):
179 # MATCH ROM
180 break
181 elif (self.net_cmd == 0xf0):
182 # SEARCH ROM
183 break
184 elif (self.net_cmd == 0x3c):
185 # OVERDRIVE SKIP ROM
186 break
187 elif (self.net_cmd == 0x69):
188 # OVERDRIVE MATCH ROM
189 break
190 self.net_cnt = 0
191 elif (self.net_state == "WAIT FOR ROM"):
192 #
193 break
194 else:
195 raise Exception('Invalid net_state: %d' % self.net_state)
196 elif not (self.lnk_event == "NONE"):
197 raise Exception('Invalid lnk_event: %s' % self.lnk_event)
198
199
200# if (self.samplenum == self.lnk_start + 8*self.time_base):
201# self.put(self.lnk_fall, self.samplenum - 1, self.out_proto, ['RESET'])