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03325c23 GM |
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 | ||
9611dc5f | 21 | # |
03325c23 | 22 | # USB Full-speed protocol decoder |
9611dc5f UH |
23 | # |
24 | # Full-speed USB signalling consists of two signal lines, both driven at 3.3V | |
25 | # logic levels. The signals are DP (D+) and DM (D-), and normally operate in | |
26 | # differential mode. | |
03325c23 | 27 | # The state where DP=1,DM=0 is J, the state DP=0,DM=1 is K. |
9611dc5f | 28 | # A state SE0 is defined where DP=DM=0. This common mode signal is used to |
03325c23 | 29 | # signal a reset or end of packet. |
9611dc5f UH |
30 | # |
31 | # Data transmitted on the USB is encoded with NRZI. A transition from J to K | |
32 | # or vice-versa indicates a logic 0, while no transition indicates a logic 1. | |
33 | # If 6 ones are transmitted consecutively, a zero is inserted to force a | |
34 | # transition. This is known as bit stuffing. Data is transferred at a rate | |
35 | # of 12Mbit/s. The SE0 transmitted to signal an end-of-packet is two bit | |
03325c23 | 36 | # intervals long. |
9611dc5f UH |
37 | # |
38 | # Details: | |
39 | # https://en.wikipedia.org/wiki/USB | |
40 | # http://www.usb.org/developers/docs/ | |
41 | # | |
03325c23 | 42 | |
677d597b | 43 | import sigrokdecode as srd |
03325c23 | 44 | |
9611dc5f | 45 | # States |
03325c23 | 46 | SE0, J, K, SE1 = 0, 1, 2, 3 |
0690a587 UH |
47 | |
48 | # ... | |
03325c23 | 49 | syms = { |
c66baa8c UH |
50 | (0, 0): SE0, |
51 | (1, 0): J, | |
52 | (0, 1): K, | |
53 | (1, 1): SE1, | |
03325c23 GM |
54 | } |
55 | ||
bbe99ad5 UH |
56 | # ... |
57 | pids = { | |
58 | '10000111': 'OUT', # Tokens | |
59 | '10010110': 'IN', | |
60 | '10100101': 'SOF', | |
61 | '10110100': 'SETUP', | |
62 | '11000011': 'DATA0', # Data | |
63 | '11010010': 'DATA1', | |
64 | '01001011': 'ACK', # Handshake | |
65 | '01011010': 'NAK', | |
66 | '01111000': 'STALL', | |
67 | '01101001': 'NYET', | |
68 | } | |
69 | ||
03325c23 | 70 | def bitstr_to_num(bitstr): |
eb7082c9 UH |
71 | if not bitstr: |
72 | return 0 | |
03325c23 GM |
73 | l = list(bitstr) |
74 | l.reverse() | |
75 | return int(''.join(l), 2) | |
76 | ||
77 | def packet_decode(packet): | |
03325c23 GM |
78 | sync = packet[:8] |
79 | pid = packet[8:16] | |
80 | pid = pids.get(pid, pid) | |
eb7082c9 | 81 | |
9611dc5f | 82 | # Remove CRC. |
03325c23 GM |
83 | if pid in ('OUT', 'IN', 'SOF', 'SETUP'): |
84 | data = packet[16:-5] | |
85 | if pid == 'SOF': | |
86 | data = str(bitstr_to_num(data)) | |
87 | else: | |
88 | dev = bitstr_to_num(data[:7]) | |
89 | ep = bitstr_to_num(data[7:]) | |
eb7082c9 | 90 | data = 'DEV %d EP %d' % (dev, ep) |
03325c23 GM |
91 | |
92 | elif pid in ('DATA0', 'DATA1'): | |
93 | data = packet[16:-16] | |
eb7082c9 | 94 | tmp = '' |
03325c23 | 95 | while data: |
0690a587 | 96 | tmp += '%02x ' % bitstr_to_num(data[:8]) |
03325c23 GM |
97 | data = data[8:] |
98 | data = tmp | |
99 | else: | |
100 | data = packet[16:] | |
101 | ||
eb7082c9 UH |
102 | if sync != '00000001': |
103 | return 'SYNC INVALID!' | |
9611dc5f | 104 | |
03325c23 GM |
105 | return pid + ' ' + data |
106 | ||
677d597b | 107 | class Decoder(srd.Decoder): |
67e847fd | 108 | id = 'usb' |
03325c23 | 109 | name = 'USB' |
0690a587 | 110 | longname = 'Universal Serial Bus' |
9a12a6e7 | 111 | desc = 'Universal Serial Bus' |
03325c23 GM |
112 | longdesc = '...longdesc...' |
113 | author = 'Gareth McMullin' | |
114 | email = 'gareth@blacksphere.co.nz' | |
115 | license = 'gplv2+' | |
116 | inputs = ['logic'] | |
117 | outputs = ['usb'] | |
ea42f53e UH |
118 | probes = [ |
119 | {'id': 'dp', 'name': 'D+', 'desc': 'USB D+ signal'}, | |
120 | {'id': 'dm', 'name': 'D-', 'desc': 'USB D- signal'}, | |
121 | ] | |
03325c23 | 122 | options = {} |
0690a587 UH |
123 | annotations = [ |
124 | ['TODO', 'TODO'] | |
125 | ] | |
03325c23 GM |
126 | |
127 | def __init__(self): | |
d0e93c76 | 128 | pass |
03325c23 GM |
129 | |
130 | def start(self, metadata): | |
03325c23 | 131 | self.rate = metadata['samplerate'] |
0690a587 | 132 | |
56202222 UH |
133 | # self.out_proto = self.add(srd.OUTPUT_PROTO, 'usb') |
134 | self.out_ann = self.add(srd.OUTPUT_ANN, 'usb') | |
0690a587 | 135 | |
03325c23 | 136 | if self.rate < 48000000: |
eb7082c9 | 137 | raise Exception('Sample rate not sufficient for USB decoding') |
0690a587 | 138 | |
9611dc5f | 139 | # Initialise decoder state. |
03325c23 GM |
140 | self.sym = J |
141 | self.scount = 0 | |
142 | self.packet = '' | |
143 | ||
2b9837d9 | 144 | def decode(self, ss, es, data): |
b327337f | 145 | |
ea42f53e | 146 | # FIXME |
0690a587 UH |
147 | # for (samplenum, (dp, dm, x, y, z, a)) in data: |
148 | for (samplenum, (dm, dp)) in data: | |
03325c23 GM |
149 | |
150 | self.scount += 1 | |
151 | ||
ea42f53e | 152 | sym = syms[dp, dm] |
0690a587 UH |
153 | |
154 | # ... | |
03325c23 GM |
155 | if sym == self.sym: |
156 | continue | |
157 | ||
158 | if self.scount == 1: | |
9611dc5f UH |
159 | # We ignore single sample width pulses. |
160 | # I sometimes get these with the OLS. | |
03325c23 GM |
161 | self.sym = sym |
162 | self.scount = 0 | |
163 | continue | |
164 | ||
9611dc5f | 165 | # How many bits since the last transition? |
0690a587 | 166 | if self.packet != '' or self.sym != J: |
b327337f | 167 | bitcount = int((self.scount - 1) * 12000000 / self.rate) |
03325c23 GM |
168 | else: |
169 | bitcount = 0 | |
170 | ||
171 | if self.sym == SE0: | |
172 | if bitcount == 1: | |
9611dc5f | 173 | # End-Of-Packet (EOP) |
0690a587 UH |
174 | self.put(0, 0, self.out_ann, |
175 | [0, [packet_decode(self.packet), self.packet]]) | |
03325c23 | 176 | else: |
9611dc5f | 177 | # Longer than EOP, assume reset. |
0690a587 | 178 | self.put(0, 0, self.out_ann, [0, ['RESET']]) |
03325c23 GM |
179 | self.scount = 0 |
180 | self.sym = sym | |
181 | self.packet = '' | |
182 | continue | |
183 | ||
184 | # Add bits to the packet string. | |
185 | self.packet += '1' * bitcount | |
0690a587 | 186 | |
9611dc5f | 187 | # Handle bit stuffing. |
03325c23 GM |
188 | if bitcount < 6 and sym != SE0: |
189 | self.packet += '0' | |
190 | elif bitcount > 6: | |
0690a587 | 191 | self.put(0, 0, self.out_ann, [0, ['BIT STUFF ERROR']]) |
9611dc5f | 192 | |
03325c23 GM |
193 | self.scount = 0 |
194 | self.sym = sym | |
195 |