2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2011 Gareth McMullin <gareth@blacksphere.co.nz>
5 ## Copyright (C) 2012-2014 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 [<ptype>, <data1>, <data2>]
31 - 'DATA': <data1> contains the MOSI data, <data2> contains the MISO data.
32 The data is _usually_ 8 bits (but can also be fewer or more bits).
33 Both data items are Python numbers (not strings), or None if the respective
34 channel was not supplied.
35 - 'BITS': <data1>/<data2> contain a list of bit values in this MOSI/MISO data
36 item, and for each of those also their respective start-/endsample numbers.
37 - 'CS CHANGE': <data1> is the old CS# pin value, <data2> is the new value.
38 Both data items are Python numbers (0/1), not strings. At the beginning of
39 the decoding a packet is generated with <data1> = -1 and <data2> being the
40 initial state of the CS# pin or -1 if the chip select pin is not supplied.
45 ['BITS', [[1, 80, 82], [1, 83, 84], [1, 85, 86], [1, 87, 88],
46 [1, 89, 90], [1, 91, 92], [1, 93, 94], [1, 95, 96]],
47 [[0, 80, 82], [1, 83, 84], [0, 85, 86], [1, 87, 88],
48 [1, 89, 90], [1, 91, 92], [0, 93, 94], [0, 95, 96]]]
55 # Key: (CPOL, CPHA). Value: SPI mode.
56 # Clock polarity (CPOL) = 0/1: Clock is low/high when inactive.
57 # Clock phase (CPHA) = 0/1: Data is valid on the leading/trailing clock edge.
65 class SamplerateError(Exception):
68 class ChannelError(Exception):
71 class Decoder(srd.Decoder):
75 longname = 'Serial Peripheral Interface'
76 desc = 'Full-duplex, synchronous, serial bus.'
81 {'id': 'clk', 'name': 'CLK', 'desc': 'Clock'},
84 {'id': 'miso', 'name': 'MISO', 'desc': 'Master in, slave out'},
85 {'id': 'mosi', 'name': 'MOSI', 'desc': 'Master out, slave in'},
86 {'id': 'cs', 'name': 'CS#', 'desc': 'Chip-select'},
89 {'id': 'cs_polarity', 'desc': 'CS# polarity', 'default': 'active-low',
90 'values': ('active-low', 'active-high')},
91 {'id': 'cpol', 'desc': 'Clock polarity', 'default': 0,
93 {'id': 'cpha', 'desc': 'Clock phase', 'default': 0,
95 {'id': 'bitorder', 'desc': 'Bit order',
96 'default': 'msb-first', 'values': ('msb-first', 'lsb-first')},
97 {'id': 'wordsize', 'desc': 'Word size', 'default': 8},
100 ('miso-data', 'MISO data'),
101 ('mosi-data', 'MOSI data'),
102 ('miso-bits', 'MISO bits'),
103 ('mosi-bits', 'MOSI bits'),
104 ('warnings', 'Human-readable warnings'),
107 ('miso-data', 'MISO data', (0,)),
108 ('miso-bits', 'MISO bits', (2,)),
109 ('mosi-data', 'MOSI data', (1,)),
110 ('mosi-bits', 'MOSI bits', (3,)),
111 ('other', 'Other', (4,)),
115 self.samplerate = None
118 self.misodata = self.mosidata = 0
123 self.cs_was_deasserted = False
126 self.have_cs = self.have_miso = self.have_mosi = None
127 self.no_cs_notification = False
129 def metadata(self, key, value):
130 if key == srd.SRD_CONF_SAMPLERATE:
131 self.samplerate = value
134 self.out_python = self.register(srd.OUTPUT_PYTHON)
135 self.out_ann = self.register(srd.OUTPUT_ANN)
136 self.out_bitrate = self.register(srd.OUTPUT_META,
137 meta=(int, 'Bitrate', 'Bitrate during transfers'))
139 def putw(self, data):
140 self.put(self.ss_block, self.samplenum, self.out_ann, data)
143 # Pass MISO and MOSI bits and then data to the next PD up the stack.
144 so = self.misodata if self.have_miso else None
145 si = self.mosidata if self.have_mosi else None
146 so_bits = self.misobits if self.have_miso else None
147 si_bits = self.mosibits if self.have_mosi else None
150 ss, es = self.misobits[-1][1], self.misobits[0][2]
152 ss, es = self.mosibits[-1][1], self.mosibits[0][2]
154 self.put(ss, es, self.out_python, ['BITS', si_bits, so_bits])
155 self.put(ss, es, self.out_python, ['DATA', si, so])
159 for bit in self.misobits:
160 self.put(bit[1], bit[2], self.out_ann, [2, ['%d' % bit[0]]])
162 for bit in self.mosibits:
163 self.put(bit[1], bit[2], self.out_ann, [3, ['%d' % bit[0]]])
165 # Dataword annotations.
167 self.put(ss, es, self.out_ann, [0, ['%02X' % self.misodata]])
169 self.put(ss, es, self.out_ann, [1, ['%02X' % self.mosidata]])
171 def reset_decoder_state(self):
172 self.misodata = 0 if self.have_miso else None
173 self.mosidata = 0 if self.have_mosi else None
174 self.misobits = [] if self.have_miso else None
175 self.mosibits = [] if self.have_mosi else None
178 def handle_bit(self, miso, mosi, clk, cs):
179 # If this is the first bit of a dataword, save its sample number.
180 if self.bitcount == 0:
181 self.ss_block = self.samplenum
182 self.cs_was_deasserted = False
184 active_low = (self.options['cs_polarity'] == 'active-low')
185 self.cs_was_deasserted = (cs == 1) if active_low else (cs == 0)
187 ws = self.options['wordsize']
189 # Receive MISO bit into our shift register.
191 if self.options['bitorder'] == 'msb-first':
192 self.misodata |= miso << (ws - 1 - self.bitcount)
194 self.misodata |= miso << self.bitcount
196 # Receive MOSI bit into our shift register.
198 if self.options['bitorder'] == 'msb-first':
199 self.mosidata |= mosi << (ws - 1 - self.bitcount)
201 self.mosidata |= mosi << self.bitcount
203 # Guesstimate the endsample for this bit (can be overridden below).
205 if self.bitcount > 0:
207 es += self.samplenum - self.misobits[0][1]
209 es += self.samplenum - self.mosibits[0][1]
212 self.misobits.insert(0, [miso, self.samplenum, es])
214 self.mosibits.insert(0, [mosi, self.samplenum, es])
216 if self.bitcount > 0 and self.have_miso:
217 self.misobits[1][2] = self.samplenum
218 if self.bitcount > 0 and self.have_mosi:
219 self.mosibits[1][2] = self.samplenum
223 # Continue to receive if not enough bits were received, yet.
224 if self.bitcount != ws:
230 elapsed = 1 / float(self.samplerate)
231 elapsed *= (self.samplenum - self.ss_block + 1)
232 bitrate = int(1 / elapsed * self.options['wordsize'])
233 self.put(self.ss_block, self.samplenum, self.out_bitrate, bitrate)
235 if self.have_cs and self.cs_was_deasserted:
236 self.putw([4, ['CS# was deasserted during this data word!']])
238 self.reset_decoder_state()
240 def find_clk_edge(self, miso, mosi, clk, cs):
241 if self.have_cs and self.oldcs != cs:
242 # Send all CS# pin value changes.
243 self.put(self.samplenum, self.samplenum, self.out_python,
244 ['CS-CHANGE', self.oldcs, cs])
246 # Reset decoder state when CS# changes (and the CS# pin is used).
247 self.reset_decoder_state()
249 # Ignore sample if the clock pin hasn't changed.
250 if clk == self.oldclk:
255 # Sample data on rising/falling clock edge (depends on mode).
256 mode = spi_mode[self.options['cpol'], self.options['cpha']]
257 if mode == 0 and clk == 0: # Sample on rising clock edge
259 elif mode == 1 and clk == 1: # Sample on falling clock edge
261 elif mode == 2 and clk == 1: # Sample on falling clock edge
263 elif mode == 3 and clk == 0: # Sample on rising clock edge
266 # Found the correct clock edge, now get the SPI bit(s).
267 self.handle_bit(miso, mosi, clk, cs)
269 def decode(self, ss, es, data):
270 if not self.samplerate:
271 raise SamplerateError('Cannot decode without samplerate.')
272 # Either MISO or MOSI can be omitted (but not both). CS# is optional.
273 for (self.samplenum, pins) in data:
275 # Ignore identical samples early on (for performance reasons).
276 if self.oldpins == pins:
278 self.oldpins, (clk, miso, mosi, cs) = pins, pins
279 self.have_miso = (miso in (0, 1))
280 self.have_mosi = (mosi in (0, 1))
281 self.have_cs = (cs in (0, 1))
283 # Either MISO or MOSI (but not both) can be omitted.
284 if not (self.have_miso or self.have_mosi):
285 raise ChannelError('Either MISO or MOSI (or both) pins required.')
287 # Tell stacked decoders that we don't have a CS# signal.
288 if not self.no_cs_notification and not self.have_cs:
289 self.put(0, 0, self.out_python, ['CS-CHANGE', -1, -1])
290 self.no_cs_notification = True
292 self.find_clk_edge(miso, mosi, clk, cs)