2 ## This file is part of the sigrok project.
4 ## Copyright (C) 2011 Gareth McMullin <gareth@blacksphere.co.nz>
5 ## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
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.
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.
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
22 import sigrokdecode as srd
28 # Clock polarity options
29 CPOL_0 = 0 # Clock is low when inactive
30 CPOL_1 = 1 # Clock is high when inactive
33 CPHA_0 = 0 # Data is valid on the leading clock edge
34 CPHA_1 = 1 # Data is valid on the trailing clock edge
50 class Decoder(srd.Decoder):
53 longname = 'Serial Peripheral Interface'
55 longdesc = '...longdesc...'
60 {'id': 'mosi', 'name': 'MOSI',
61 'desc': 'SPI MOSI line (Master out, slave in)'},
62 {'id': 'miso', 'name': 'MISO',
63 'desc': 'SPI MISO line (Master in, slave out)'},
64 {'id': 'sck', 'name': 'CLK', 'desc': 'SPI clock line'},
65 {'id': 'cs', 'name': 'CS#', 'desc': 'SPI CS (chip select) line'},
68 'cs_polarity': ['CS# polarity', ACTIVE_LOW],
69 'cpol': ['Clock polarity', CPOL_0],
70 'cpha': ['Clock phase', CPHA_0],
71 'bitorder': ['Bit order within the SPI data', MSB_FIRST],
72 'wordsize': ['Word size of SPI data', 8], # 1-64?
75 ['Hex', 'SPI data bytes in hex format'],
83 self.bytesreceived = 0
85 self.cs_was_deasserted_during_data_word = 0
87 # Set protocol decoder option defaults.
88 self.cs_polarity = Decoder.options['cs_polarity'][1]
89 self.cpol = Decoder.options['cpol'][1]
90 self.cpha = Decoder.options['cpha'][1]
91 self.bitorder = Decoder.options['bitorder'][1]
92 self.wordsize = Decoder.options['wordsize'][1]
94 def start(self, metadata):
95 self.out_proto = self.add(srd.OUTPUT_PROTO, 'spi')
96 self.out_ann = self.add(srd.OUTPUT_ANN, 'spi')
99 return 'SPI: %d bytes received' % self.bytesreceived
101 def decode(self, ss, es, data):
102 # HACK! At the moment the number of probes is not handled correctly.
103 # E.g. if an input file (-i foo.sr) has more than two probes enabled.
104 # for (samplenum, (mosi, sck, x, y, z, a)) in data:
105 # for (samplenum, (cs, miso, sck, mosi, wp, hold)) in data:
106 for (samplenum, (cs, miso, sck, mosi, wp, hold)) in data:
108 self.samplenum += 1 # FIXME
110 # Ignore sample if the clock pin hasn't changed.
111 if sck == self.oldsck:
116 # Sample data on rising/falling clock edge (depends on mode).
117 mode = spi_mode[self.cpol, self.cpha]
118 if mode == 0 and sck == 0: # Sample on rising clock edge
120 elif mode == 1 and sck == 1: # Sample on falling clock edge
122 elif mode == 2 and sck == 1: # Sample on falling clock edge
124 elif mode == 3 and sck == 0: # Sample on rising clock edge
127 # If this is the first bit, save its sample number.
128 if self.bitcount == 0:
129 self.start_sample = samplenum
130 deasserted = cs if (self.cs_polarity == ACTIVE_LOW) else not c
132 self.cs_was_deasserted_during_data_word = 1
134 # Receive MOSI bit into our shift register.
135 if self.bitorder == MSB_FIRST:
136 self.mosidata |= mosi << (self.wordsize - 1 - self.bitcount)
138 self.mosidata |= mosi << self.bitcount
140 # Receive MISO bit into our shift register.
141 if self.bitorder == MSB_FIRST:
142 self.misodata |= miso << (self.wordsize - 1 - self.bitcount)
144 self.misodata |= miso << self.bitcount
148 # Continue to receive if not a byte yet.
149 if self.bitcount != self.wordsize:
152 self.put(self.start_sample, self.samplenum, self.out_proto,
153 ['data', self.mosidata, self.misodata])
154 self.put(self.start_sample, self.samplenum, self.out_ann,
155 [ANN_HEX, ['MOSI: 0x%02x, MISO: 0x%02x' % (self.mosidata,
158 if self.cs_was_deasserted_during_data_word:
159 self.put(self.start_sample, self.samplenum, self.out_ann,
160 [ANN_HEX, ['WARNING: CS# was deasserted during this '
163 # Reset decoder state.
168 # Keep stats for summary.
169 self.bytesreceived += 1