## ## This file is part of the libsigrokdecode project. ## ## Copyright (C) 2011 Gareth McMullin ## Copyright (C) 2012-2014 Uwe Hermann ## ## This program is free software; you can redistribute it and/or modify ## it under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 2 of the License, or ## (at your option) any later version. ## ## This program is distributed in the hope that it will be useful, ## but WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ## GNU General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with this program; if not, write to the Free Software ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA ## import sigrokdecode as srd ''' OUTPUT_PYTHON format: Packet: [, , ] : - 'DATA': contains the MOSI data, contains the MISO data. The data is _usually_ 8 bits (but can also be fewer or more bits). Both data items are Python numbers (not strings), or None if the respective channel was not supplied. - 'BITS': / contain a list of bit values in this MOSI/MISO data item, and for each of those also their respective start-/endsample numbers. - 'CS CHANGE': is the old CS# pin value, is the new value. Both data items are Python numbers (0/1), not strings. At the beginning of the decoding a packet is generated with = None and being the initial state of the CS# pin or None if the chip select pin is not supplied. Examples: ['CS-CHANGE', None, 1] ['CS-CHANGE', 1, 0] ['DATA', 0xff, 0x3a] ['BITS', [[1, 80, 82], [1, 83, 84], [1, 85, 86], [1, 87, 88], [1, 89, 90], [1, 91, 92], [1, 93, 94], [1, 95, 96]], [[0, 80, 82], [1, 83, 84], [0, 85, 86], [1, 87, 88], [1, 89, 90], [1, 91, 92], [0, 93, 94], [0, 95, 96]]] ['DATA', 0x65, 0x00] ['DATA', 0xa8, None] ['DATA', None, 0x55] ['CS-CHANGE', 0, 1] ''' # Key: (CPOL, CPHA). Value: SPI mode. # Clock polarity (CPOL) = 0/1: Clock is low/high when inactive. # Clock phase (CPHA) = 0/1: Data is valid on the leading/trailing clock edge. spi_mode = { (0, 0): 0, # Mode 0 (0, 1): 1, # Mode 1 (1, 0): 2, # Mode 2 (1, 1): 3, # Mode 3 } class SamplerateError(Exception): pass class ChannelError(Exception): pass class Decoder(srd.Decoder): api_version = 2 id = 'spi' name = 'SPI' longname = 'Serial Peripheral Interface' desc = 'Full-duplex, synchronous, serial bus.' license = 'gplv2+' inputs = ['logic'] outputs = ['spi'] channels = ( {'id': 'clk', 'name': 'CLK', 'desc': 'Clock'}, ) optional_channels = ( {'id': 'miso', 'name': 'MISO', 'desc': 'Master in, slave out'}, {'id': 'mosi', 'name': 'MOSI', 'desc': 'Master out, slave in'}, {'id': 'cs', 'name': 'CS#', 'desc': 'Chip-select'}, ) options = ( {'id': 'cs_polarity', 'desc': 'CS# polarity', 'default': 'active-low', 'values': ('active-low', 'active-high')}, {'id': 'cpol', 'desc': 'Clock polarity', 'default': 0, 'values': (0, 1)}, {'id': 'cpha', 'desc': 'Clock phase', 'default': 0, 'values': (0, 1)}, {'id': 'bitorder', 'desc': 'Bit order', 'default': 'msb-first', 'values': ('msb-first', 'lsb-first')}, {'id': 'wordsize', 'desc': 'Word size', 'default': 8}, ) annotations = ( ('miso-data', 'MISO data'), ('mosi-data', 'MOSI data'), ('miso-bits', 'MISO bits'), ('mosi-bits', 'MOSI bits'), ('warnings', 'Human-readable warnings'), ) annotation_rows = ( ('miso-data', 'MISO data', (0,)), ('miso-bits', 'MISO bits', (2,)), ('mosi-data', 'MOSI data', (1,)), ('mosi-bits', 'MOSI bits', (3,)), ('other', 'Other', (4,)), ) def __init__(self): self.samplerate = None self.oldclk = 1 self.bitcount = 0 self.misodata = self.mosidata = 0 self.misobits = [] self.mosibits = [] self.ss_block = -1 self.samplenum = -1 self.cs_was_deasserted = False self.oldcs = None self.oldpins = None self.have_cs = self.have_miso = self.have_mosi = None self.no_cs_notification = False def metadata(self, key, value): if key == srd.SRD_CONF_SAMPLERATE: self.samplerate = value def start(self): self.out_python = self.register(srd.OUTPUT_PYTHON) self.out_ann = self.register(srd.OUTPUT_ANN) self.out_bitrate = self.register(srd.OUTPUT_META, meta=(int, 'Bitrate', 'Bitrate during transfers')) def putw(self, data): self.put(self.ss_block, self.samplenum, self.out_ann, data) def putdata(self): # Pass MISO and MOSI bits and then data to the next PD up the stack. so = self.misodata if self.have_miso else None si = self.mosidata if self.have_mosi else None so_bits = self.misobits if self.have_miso else None si_bits = self.mosibits if self.have_mosi else None if self.have_miso: ss, es = self.misobits[-1][1], self.misobits[0][2] if self.have_mosi: ss, es = self.mosibits[-1][1], self.mosibits[0][2] self.put(ss, es, self.out_python, ['BITS', si_bits, so_bits]) self.put(ss, es, self.out_python, ['DATA', si, so]) # Bit annotations. if self.have_miso: for bit in self.misobits: self.put(bit[1], bit[2], self.out_ann, [2, ['%d' % bit[0]]]) if self.have_mosi: for bit in self.mosibits: self.put(bit[1], bit[2], self.out_ann, [3, ['%d' % bit[0]]]) # Dataword annotations. if self.have_miso: self.put(ss, es, self.out_ann, [0, ['%02X' % self.misodata]]) if self.have_mosi: self.put(ss, es, self.out_ann, [1, ['%02X' % self.mosidata]]) def reset_decoder_state(self): self.misodata = 0 if self.have_miso else None self.mosidata = 0 if self.have_mosi else None self.misobits = [] if self.have_miso else None self.mosibits = [] if self.have_mosi else None self.bitcount = 0 def handle_bit(self, miso, mosi, clk, cs): # If this is the first bit of a dataword, save its sample number. if self.bitcount == 0: self.ss_block = self.samplenum self.cs_was_deasserted = False if self.have_cs: active_low = (self.options['cs_polarity'] == 'active-low') self.cs_was_deasserted = (cs == 1) if active_low else (cs == 0) ws = self.options['wordsize'] # Receive MISO bit into our shift register. if self.have_miso: if self.options['bitorder'] == 'msb-first': self.misodata |= miso << (ws - 1 - self.bitcount) else: self.misodata |= miso << self.bitcount # Receive MOSI bit into our shift register. if self.have_mosi: if self.options['bitorder'] == 'msb-first': self.mosidata |= mosi << (ws - 1 - self.bitcount) else: self.mosidata |= mosi << self.bitcount # Guesstimate the endsample for this bit (can be overridden below). es = self.samplenum if self.bitcount > 0: if self.have_miso: es += self.samplenum - self.misobits[0][1] elif self.have_mosi: es += self.samplenum - self.mosibits[0][1] if self.have_miso: self.misobits.insert(0, [miso, self.samplenum, es]) if self.have_mosi: self.mosibits.insert(0, [mosi, self.samplenum, es]) if self.bitcount > 0 and self.have_miso: self.misobits[1][2] = self.samplenum if self.bitcount > 0 and self.have_mosi: self.mosibits[1][2] = self.samplenum self.bitcount += 1 # Continue to receive if not enough bits were received, yet. if self.bitcount != ws: return self.putdata() # Meta bitrate. elapsed = 1 / float(self.samplerate) elapsed *= (self.samplenum - self.ss_block + 1) bitrate = int(1 / elapsed * self.options['wordsize']) self.put(self.ss_block, self.samplenum, self.out_bitrate, bitrate) if self.have_cs and self.cs_was_deasserted: self.putw([4, ['CS# was deasserted during this data word!']]) self.reset_decoder_state() def find_clk_edge(self, miso, mosi, clk, cs): if self.have_cs and self.oldcs != cs: # Send all CS# pin value changes. self.put(self.samplenum, self.samplenum, self.out_python, ['CS-CHANGE', self.oldcs, cs]) self.oldcs = cs # Reset decoder state when CS# changes (and the CS# pin is used). self.reset_decoder_state() # Ignore sample if the clock pin hasn't changed. if clk == self.oldclk: return self.oldclk = clk # Sample data on rising/falling clock edge (depends on mode). mode = spi_mode[self.options['cpol'], self.options['cpha']] if mode == 0 and clk == 0: # Sample on rising clock edge return elif mode == 1 and clk == 1: # Sample on falling clock edge return elif mode == 2 and clk == 1: # Sample on falling clock edge return elif mode == 3 and clk == 0: # Sample on rising clock edge return # Found the correct clock edge, now get the SPI bit(s). self.handle_bit(miso, mosi, clk, cs) def decode(self, ss, es, data): if not self.samplerate: raise SamplerateError('Cannot decode without samplerate.') # Either MISO or MOSI can be omitted (but not both). CS# is optional. for (self.samplenum, pins) in data: # Ignore identical samples early on (for performance reasons). if self.oldpins == pins: continue self.oldpins, (clk, miso, mosi, cs) = pins, pins self.have_miso = (miso in (0, 1)) self.have_mosi = (mosi in (0, 1)) self.have_cs = (cs in (0, 1)) # Either MISO or MOSI (but not both) can be omitted. if not (self.have_miso or self.have_mosi): raise ChannelError('Either MISO or MOSI (or both) pins required.') # Tell stacked decoders that we don't have a CS# signal. if not self.no_cs_notification and not self.have_cs: self.put(0, 0, self.out_python, ['CS-CHANGE', None, None]) self.no_cs_notification = True self.find_clk_edge(miso, mosi, clk, cs)