2 ## This file is part of the sigrok project.
4 ## Copyright (C) 2012 Iztok Jeras <iztok.jeras@gmail.com>
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.
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.
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
21 # 1-Wire link layer protocol decoder
23 import sigrokdecode as srd
25 class Decoder(srd.Decoder):
28 name = '1-Wire link layer'
29 longname = '1-Wire serial communication bus'
30 desc = 'Bidirectional, half-duplex, asynchronous serial bus.'
33 outputs = ['onewire_link']
35 {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire bus'},
38 {'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power'},
41 'overdrive' : ['Overdrive', 1],
42 'cnt_normal_bit' : ['Time (in samplerate periods) for normal mode sample bit' , 0],
43 'cnt_normal_presence' : ['Time (in samplerate periods) for normal mode sample presence', 0],
44 'cnt_normal_reset' : ['Time (in samplerate periods) for normal mode reset' , 0],
45 'cnt_overdrive_bit' : ['Time (in samplerate periods) for overdrive mode sample bit' , 0],
46 'cnt_overdrive_presence': ['Time (in samplerate periods) for overdrive mode sample presence', 0],
47 'cnt_overdrive_reset' : ['Time (in samplerate periods) for overdrive mode reset' , 0],
50 ['Link', 'Link layer events (reset, presence, bit slots)'],
53 def __init__(self, **kwargs):
56 # Link layer variables
57 self.state = 'WAIT FOR FALLING EDGE'
62 # Event timing variables
66 def start(self, metadata):
67 self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire_link')
68 self.out_ann = self.add(srd.OUTPUT_ANN , 'onewire_link')
70 # check if samplerate is appropriate
71 self.samplerate = metadata['samplerate']
72 if (self.options['overdrive']):
73 self.put(0, 0, self.out_ann, [0,
74 ['NOTE: Sample rate checks assume overdrive mode.']])
75 if (self.samplerate < 2000000):
76 self.put(0, 0, self.out_ann, [0,
77 ['ERROR: Sampling rate is too low must be above 2MHz for proper overdrive mode decoding.']])
78 elif (self.samplerate < 5000000):
79 self.put(0, 0, self.out_ann, [0,
80 ['WARNING: Sampling rate is suggested to be above 5MHz for proper overdrive mode decoding.']])
82 self.put(0, 0, self.out_ann, [0,
83 ['NOTE: Sample rate checks assume normal mode only.']])
84 if (self.samplerate < 400000):
85 self.put(0, 0, self.out_ann, [0,
86 ['ERROR: Sampling rate is too low must be above 400kHz for proper normal mode decoding.']])
87 elif (self.samplerate < 1000000):
88 self.put(0, 0, self.out_ann, [0,
89 ['WARNING: Sampling rate is suggested to be above 1MHz for proper normal mode decoding.']])
91 # The default 1-Wire time base is 30us, this is used to calculate sampling times.
92 if (self.options['cnt_normal_bit']):
93 self.cnt_normal_bit = self.options['cnt_normal_bit']
95 self.cnt_normal_bit = int(float(self.samplerate) * 0.000015) - 1 # 15ns
96 if (self.options['cnt_normal_presence']):
97 self.cnt_normal_presence = self.options['cnt_normal_presence']
99 self.cnt_normal_presence = int(float(self.samplerate) * 0.000075) - 1 # 75ns
100 if (self.options['cnt_normal_reset']):
101 self.cnt_normal_reset = self.options['cnt_normal_reset']
103 self.cnt_normal_reset = int(float(self.samplerate) * 0.000480) - 1 # 480ns
104 if (self.options['cnt_overdrive_bit']):
105 self.cnt_overdrive_bit = self.options['cnt_overdrive_bit']
107 self.cnt_overdrive_bit = int(float(self.samplerate) * 0.000002) - 1 # 2ns
108 if (self.options['cnt_overdrive_presence']):
109 self.cnt_overdrive_presence = self.options['cnt_overdrive_presence']
111 self.cnt_overdrive_presence = int(float(self.samplerate) * 0.000010) - 1 # 10ns
112 if (self.options['cnt_overdrive_reset']):
113 self.cnt_overdrive_reset = self.options['cnt_overdrive_reset']
115 self.cnt_overdrive_reset = int(float(self.samplerate) * 0.000048) - 1 # 48ns
117 # calculating the slot size
118 self.cnt_normal_slot = int(float(self.samplerate) * 0.000060) - 1 # 60ns
119 self.cnt_overdrive_slot = int(float(self.samplerate) * 0.000006) - 1 # 6ns
121 # organize values into lists
122 self.cnt_bit = [self.cnt_normal_bit , self.cnt_overdrive_bit ]
123 self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence]
124 self.cnt_reset = [self.cnt_normal_reset , self.cnt_overdrive_reset ]
125 self.cnt_slot = [self.cnt_normal_slot , self.cnt_overdrive_slot ]
127 # Check if sample times are in the allowed range
128 time_min = float(self.cnt_normal_bit ) / self.samplerate
129 time_max = float(self.cnt_normal_bit+1) / self.samplerate
130 if ( (time_min < 0.000005) or (time_max > 0.000015) ) :
131 self.put(0, 0, self.out_ann, [0,
132 ['WARNING: The normal mode data sample time interval (%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).'
133 % (time_min*1000000, time_max*1000000)]])
134 time_min = float(self.cnt_normal_presence ) / self.samplerate
135 time_max = float(self.cnt_normal_presence+1) / self.samplerate
136 if ( (time_min < 0.0000681) or (time_max > 0.000075) ) :
137 self.put(0, 0, self.out_ann, [0,
138 ['WARNING: The normal mode presence sample time interval (%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).'
139 % (time_min*1000000, time_max*1000000)]])
140 time_min = float(self.cnt_overdrive_bit ) / self.samplerate
141 time_max = float(self.cnt_overdrive_bit+1) / self.samplerate
142 if ( (time_min < 0.000001) or (time_max > 0.000002) ) :
143 self.put(0, 0, self.out_ann, [0,
144 ['WARNING: The overdrive mode data sample time interval (%2.1fus-%2.1fus) should be inside (1.0us, 2.0us).'
145 % (time_min*1000000, time_max*1000000)]])
146 time_min = float(self.cnt_overdrive_presence ) / self.samplerate
147 time_max = float(self.cnt_overdrive_presence+1) / self.samplerate
148 if ( (time_min < 0.0000073) or (time_max > 0.000010) ) :
149 self.put(0, 0, self.out_ann, [0,
150 ['WARNING: The overdrive mode presence sample time interval (%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).'
151 % (time_min*1000000, time_max*1000000)]])
156 def decode(self, ss, es, data):
157 for (self.samplenum, (owr, pwr)) in data:
160 if self.state == 'WAIT FOR FALLING EDGE':
161 # The start of a cycle is a falling edge.
163 # Save the sample number for the falling edge.
164 self.fall = self.samplenum
165 # Go to waiting for sample time
166 self.state = 'WAIT FOR DATA SAMPLE'
167 elif self.state == 'WAIT FOR DATA SAMPLE':
169 if (self.samplenum - self.fall == self.cnt_bit[self.overdrive]):
171 if (self.bit): self.state = 'WAIT FOR FALLING EDGE'
172 else : self.state = 'WAIT FOR RISING EDGE'
173 self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['BIT: %01x' % self.bit]])
174 self.put(self.out_proto, ['BIT', self.bit])
175 # Checking the first command to see if overdrive mode should be entered
176 if (self.cmd_cnt <= 8):
177 self.command = self.command | (self.bit << self.cmd_cnt)
178 elif (self.cmd_cnt == 8):
179 if (self.command in [0x3c, 0x69]):
180 self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['ENTER OVERDRIVE MODE']])
181 # incrementing the bit counter
183 elif self.state == 'WAIT FOR RISING EDGE':
184 # The end of a cycle is a rising edge.
186 # Check if this was a reset cycle
187 if (self.samplenum - self.fall > self.cnt_normal_reset):
188 # Save the sample number for the falling edge.
189 self.rise = self.samplenum
190 self.state = "WAIT FOR PRESENCE DETECT"
191 self.put(self.fall, self.rise, self.out_ann, [0, ['RESET']])
192 self.put(self.fall, self.rise, self.out_proto, ['RESET', 0])
194 self.fall = self.samplenum
195 # Exit overdrive mode
196 self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['EXIT OVERDRIVE MODE']])
200 elif ((self.samplenum - self.fall > self.cnt_overdrive_reset) and (self.overdrive)):
201 # Save the sample number for the falling edge.
202 self.rise = self.samplenum
203 self.state = "WAIT FOR PRESENCE DETECT"
204 self.put(self.fall, self.rise, self.out_ann, [0, ['RESET']])
205 self.put(self.fall, self.rise, self.out_proto, ['RESET', 0])
207 self.fall = self.samplenum
208 # Otherwise this is assumed to be a data bit.
210 self.state = "WAIT FOR FALLING EDGE"
211 elif self.state == 'WAIT FOR PRESENCE DETECT':
212 # Sample presence status
213 if (self.samplenum - self.rise == self.cnt_presence[self.overdrive]):
214 self.present = owr & 0x1
215 # Save the sample number for the falling edge.
216 if not (self.present) : self.fall = self.samplenum
217 # create presence detect event
218 if (self.present) : self.state = 'WAIT FOR FALLING EDGE'
219 else : self.state = 'WAIT FOR RISING EDGE'
220 self.put(self.samplenum, 0, self.out_ann, [0, ['PRESENCE: ' + "False" if self.present else "True"]])
221 self.put(self.samplenum, 0, self.out_proto, ['PRESENCE', self.present])
223 raise Exception('Invalid state: %d' % self.state)