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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 | ## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de> | |
6 | ## | |
7 | ## This program is free software; you can redistribute it and/or modify | |
8 | ## it under the terms of the GNU General Public License as published by | |
9 | ## the Free Software Foundation; either version 2 of the License, or | |
10 | ## (at your option) any later version. | |
11 | ## | |
12 | ## This program is distributed in the hope that it will be useful, | |
13 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | ## GNU General Public License for more details. | |
16 | ## | |
17 | ## You should have received a copy of the GNU General Public License | |
18 | ## along with this program; if not, write to the Free Software | |
19 | ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | ## | |
21 | ||
22 | import sigrokdecode as srd | |
23 | ||
24 | # Chip-select options | |
25 | ACTIVE_LOW = 0 | |
26 | ACTIVE_HIGH = 1 | |
27 | ||
28 | # Clock polarity options | |
29 | CPOL_0 = 0 # Clock is low when inactive | |
30 | CPOL_1 = 1 # Clock is high when inactive | |
31 | ||
32 | # Clock phase options | |
33 | CPHA_0 = 0 # Data is valid on the leading clock edge | |
34 | CPHA_1 = 1 # Data is valid on the trailing clock edge | |
35 | ||
36 | # Bit order options | |
37 | MSB_FIRST = 0 | |
38 | LSB_FIRST = 1 | |
39 | ||
40 | spi_mode = { | |
41 | (0, 0): 0, # Mode 0 | |
42 | (0, 1): 1, # Mode 1 | |
43 | (1, 0): 2, # Mode 2 | |
44 | (1, 1): 3, # Mode 3 | |
45 | } | |
46 | ||
47 | # Annotation formats | |
48 | ANN_HEX = 0 | |
49 | ||
50 | class Decoder(srd.Decoder): | |
51 | id = 'spi' | |
52 | name = 'SPI' | |
53 | longname = 'Serial Peripheral Interface' | |
54 | desc = '...desc...' | |
55 | longdesc = '...longdesc...' | |
56 | author = 'Gareth McMullin' | |
57 | email = 'gareth@blacksphere.co.nz' | |
58 | license = 'gplv2+' | |
59 | inputs = ['logic'] | |
60 | outputs = ['spi'] | |
61 | probes = [ | |
62 | {'id': 'mosi', 'name': 'MOSI', | |
63 | 'desc': 'SPI MOSI line (Master out, slave in)'}, | |
64 | {'id': 'miso', 'name': 'MISO', | |
65 | 'desc': 'SPI MISO line (Master in, slave out)'}, | |
66 | {'id': 'sck', 'name': 'CLK', 'desc': 'SPI clock line'}, | |
67 | {'id': 'cs', 'name': 'CS#', 'desc': 'SPI CS (chip select) line'}, | |
68 | ] | |
69 | options = { | |
70 | 'cs_polarity': ['CS# polarity', ACTIVE_LOW], | |
71 | 'cpol': ['Clock polarity', CPOL_0], | |
72 | 'cpha': ['Clock phase', CPHA_0], | |
73 | 'bitorder': ['Bit order within the SPI data', MSB_FIRST], | |
74 | 'wordsize': ['Word size of SPI data', 8], # 1-64? | |
75 | } | |
76 | annotations = [ | |
77 | ['Hex', 'SPI data bytes in hex format'], | |
78 | ] | |
79 | ||
80 | def __init__(self): | |
81 | self.oldsck = 1 | |
82 | self.bitcount = 0 | |
83 | self.mosidata = 0 | |
84 | self.misodata = 0 | |
85 | self.bytesreceived = 0 | |
86 | self.samplenum = -1 | |
87 | self.cs_was_deasserted_during_data_word = 0 | |
88 | ||
89 | # Set protocol decoder option defaults. | |
90 | self.cs_polarity = Decoder.options['cs_polarity'][1] | |
91 | self.cpol = Decoder.options['cpol'][1] | |
92 | self.cpha = Decoder.options['cpha'][1] | |
93 | self.bitorder = Decoder.options['bitorder'][1] | |
94 | self.wordsize = Decoder.options['wordsize'][1] | |
95 | ||
96 | def start(self, metadata): | |
97 | self.out_proto = self.add(srd.OUTPUT_PROTO, 'spi') | |
98 | self.out_ann = self.add(srd.OUTPUT_ANN, 'spi') | |
99 | ||
100 | def report(self): | |
101 | return 'SPI: %d bytes received' % self.bytesreceived | |
102 | ||
103 | def decode(self, ss, es, data): | |
104 | # HACK! At the moment the number of probes is not handled correctly. | |
105 | # E.g. if an input file (-i foo.sr) has more than two probes enabled. | |
106 | # for (samplenum, (mosi, sck, x, y, z, a)) in data: | |
107 | # for (samplenum, (cs, miso, sck, mosi, wp, hold)) in data: | |
108 | for (samplenum, (cs, miso, sck, mosi, wp, hold)) in data: | |
109 | ||
110 | self.samplenum += 1 # FIXME | |
111 | ||
112 | # Ignore sample if the clock pin hasn't changed. | |
113 | if sck == self.oldsck: | |
114 | continue | |
115 | ||
116 | self.oldsck = sck | |
117 | ||
118 | # Sample data on rising/falling clock edge (depends on mode). | |
119 | mode = spi_mode[self.cpol, self.cpha] | |
120 | if mode == 0 and sck == 0: # Sample on rising clock edge | |
121 | continue | |
122 | elif mode == 1 and sck == 1: # Sample on falling clock edge | |
123 | continue | |
124 | elif mode == 2 and sck == 1: # Sample on falling clock edge | |
125 | continue | |
126 | elif mode == 3 and sck == 0: # Sample on rising clock edge | |
127 | continue | |
128 | ||
129 | # If this is the first bit, save its sample number. | |
130 | if self.bitcount == 0: | |
131 | self.start_sample = samplenum | |
132 | deasserted = cs if (self.cs_polarity == ACTIVE_LOW) else not c | |
133 | if deasserted: | |
134 | self.cs_was_deasserted_during_data_word = 1 | |
135 | ||
136 | # Receive MOSI bit into our shift register. | |
137 | if self.bitorder == MSB_FIRST: | |
138 | self.mosidata |= mosi << (self.wordsize - 1 - self.bitcount) | |
139 | else: | |
140 | self.mosidata |= mosi << self.bitcount | |
141 | ||
142 | # Receive MISO bit into our shift register. | |
143 | if self.bitorder == MSB_FIRST: | |
144 | self.misodata |= miso << (self.wordsize - 1 - self.bitcount) | |
145 | else: | |
146 | self.misodata |= miso << self.bitcount | |
147 | ||
148 | self.bitcount += 1 | |
149 | ||
150 | # Continue to receive if not a byte yet. | |
151 | if self.bitcount != self.wordsize: | |
152 | continue | |
153 | ||
154 | self.put(self.start_sample, self.samplenum, self.out_proto, | |
155 | ['data', self.mosidata, self.misodata]) | |
156 | self.put(self.start_sample, self.samplenum, self.out_ann, | |
157 | [ANN_HEX, ['MOSI: 0x%02x, MISO: 0x%02x' % (self.mosidata, | |
158 | self.misodata)]]) | |
159 | ||
160 | if self.cs_was_deasserted_during_data_word: | |
161 | self.put(self.start_sample, self.samplenum, self.out_ann, | |
162 | [ANN_HEX, ['WARNING: CS# was deasserted during this ' | |
163 | 'SPI data byte!']]) | |
164 | ||
165 | # Reset decoder state. | |
166 | self.mosidata = 0 | |
167 | self.misodata = 0 | |
168 | self.bitcount = 0 | |
169 | ||
170 | # Keep stats for summary. | |
171 | self.bytesreceived += 1 | |
172 |