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1 | ## | |
2 | ## This file is part of the sigrok project. | |
3 | ## | |
4 | ## Copyright (C) 2011 Gareth McMullin <gareth@blacksphere.co.nz> | |
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 | # USB (full-speed) protocol decoder | |
22 | ||
23 | import sigrokdecode as srd | |
24 | ||
25 | # States | |
26 | SE0, J, K, SE1 = 0, 1, 2, 3 | |
27 | ||
28 | # ... | |
29 | syms = { | |
30 | (0, 0): SE0, | |
31 | (1, 0): J, | |
32 | (0, 1): K, | |
33 | (1, 1): SE1, | |
34 | } | |
35 | ||
36 | # ... | |
37 | pids = { | |
38 | '10000111': 'OUT', # Tokens | |
39 | '10010110': 'IN', | |
40 | '10100101': 'SOF', | |
41 | '10110100': 'SETUP', | |
42 | '11000011': 'DATA0', # Data | |
43 | '11010010': 'DATA1', | |
44 | '01001011': 'ACK', # Handshake | |
45 | '01011010': 'NAK', | |
46 | '01111000': 'STALL', | |
47 | '01101001': 'NYET', | |
48 | } | |
49 | ||
50 | def bitstr_to_num(bitstr): | |
51 | if not bitstr: | |
52 | return 0 | |
53 | l = list(bitstr) | |
54 | l.reverse() | |
55 | return int(''.join(l), 2) | |
56 | ||
57 | def packet_decode(packet): | |
58 | sync = packet[:8] | |
59 | pid = packet[8:16] | |
60 | pid = pids.get(pid, pid) | |
61 | ||
62 | # Remove CRC. | |
63 | if pid in ('OUT', 'IN', 'SOF', 'SETUP'): | |
64 | data = packet[16:-5] | |
65 | if pid == 'SOF': | |
66 | data = str(bitstr_to_num(data)) | |
67 | else: | |
68 | dev = bitstr_to_num(data[:7]) | |
69 | ep = bitstr_to_num(data[7:]) | |
70 | data = 'DEV %d EP %d' % (dev, ep) | |
71 | ||
72 | elif pid in ('DATA0', 'DATA1'): | |
73 | data = packet[16:-16] | |
74 | tmp = '' | |
75 | while data: | |
76 | tmp += '%02x ' % bitstr_to_num(data[:8]) | |
77 | data = data[8:] | |
78 | data = tmp | |
79 | else: | |
80 | data = packet[16:] | |
81 | ||
82 | if sync != '00000001': | |
83 | return 'SYNC INVALID!' | |
84 | ||
85 | return pid + ' ' + data | |
86 | ||
87 | class Decoder(srd.Decoder): | |
88 | api_version = 1 | |
89 | id = 'usb' | |
90 | name = 'USB' | |
91 | longname = 'Universal Serial Bus' | |
92 | desc = 'Universal Serial Bus' | |
93 | longdesc = '...longdesc...' | |
94 | license = 'gplv2+' | |
95 | inputs = ['logic'] | |
96 | outputs = ['usb'] | |
97 | probes = [ | |
98 | {'id': 'dp', 'name': 'D+', 'desc': 'USB D+ signal'}, | |
99 | {'id': 'dm', 'name': 'D-', 'desc': 'USB D- signal'}, | |
100 | ] | |
101 | optional_probes = [] | |
102 | options = {} | |
103 | annotations = [ | |
104 | ['TODO', 'TODO'] | |
105 | ] | |
106 | ||
107 | def __init__(self): | |
108 | pass | |
109 | ||
110 | def start(self, metadata): | |
111 | self.rate = metadata['samplerate'] | |
112 | ||
113 | # self.out_proto = self.add(srd.OUTPUT_PROTO, 'usb') | |
114 | self.out_ann = self.add(srd.OUTPUT_ANN, 'usb') | |
115 | ||
116 | if self.rate < 48000000: | |
117 | raise Exception('Sample rate (%d) not sufficient for USB ' | |
118 | 'decoding, need at least 48MHz' % self.rate) | |
119 | ||
120 | # Initialise decoder state. | |
121 | self.sym = J | |
122 | self.scount = 0 | |
123 | self.packet = '' | |
124 | ||
125 | def report(self): | |
126 | pass | |
127 | ||
128 | def decode(self, ss, es, data): | |
129 | for (samplenum, (dm, dp)) in data: | |
130 | ||
131 | self.scount += 1 | |
132 | ||
133 | sym = syms[dp, dm] | |
134 | ||
135 | # ... | |
136 | if sym == self.sym: | |
137 | continue | |
138 | ||
139 | if self.scount == 1: | |
140 | # We ignore single sample width pulses. | |
141 | # I sometimes get these with the OLS. | |
142 | self.sym = sym | |
143 | self.scount = 0 | |
144 | continue | |
145 | ||
146 | # How many bits since the last transition? | |
147 | if self.packet != '' or self.sym != J: | |
148 | bitcount = int((self.scount - 1) * 12000000 / self.rate) | |
149 | else: | |
150 | bitcount = 0 | |
151 | ||
152 | if self.sym == SE0: | |
153 | if bitcount == 1: | |
154 | # End-Of-Packet (EOP) | |
155 | self.put(0, 0, self.out_ann, | |
156 | [0, [packet_decode(self.packet), self.packet]]) | |
157 | else: | |
158 | # Longer than EOP, assume reset. | |
159 | self.put(0, 0, self.out_ann, [0, ['RESET']]) | |
160 | self.scount = 0 | |
161 | self.sym = sym | |
162 | self.packet = '' | |
163 | continue | |
164 | ||
165 | # Add bits to the packet string. | |
166 | self.packet += '1' * bitcount | |
167 | ||
168 | # Handle bit stuffing. | |
169 | if bitcount < 6 and sym != SE0: | |
170 | self.packet += '0' | |
171 | elif bitcount > 6: | |
172 | self.put(0, 0, self.out_ann, [0, ['BIT STUFF ERROR']]) | |
173 | ||
174 | self.scount = 0 | |
175 | self.sym = sym | |
176 |