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##
## This file is part of the sigrok project.
##
## Copyright (C) 2011 Gareth McMullin <gareth@blacksphere.co.nz>
## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
##
## 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
# Chip-select options
ACTIVE_LOW = 0
ACTIVE_HIGH = 1
# Clock polarity options
CPOL_0 = 0 # Clock is low when inactive
CPOL_1 = 1 # Clock is high when inactive
# Clock phase options
CPHA_0 = 0 # Data is valid on the rising clock edge
CPHA_1 = 1 # Data is valid on the falling clock edge
# Bit order options
MSB_FIRST = 0
LSB_FIRST = 1
# Annotation formats
ANN_HEX = 0
class Decoder(srd.Decoder):
id = 'spi'
name = 'SPI'
longname = 'Serial Peripheral Interface (SPI) bus'
desc = '...desc...'
longdesc = '...longdesc...'
author = 'Gareth McMullin'
email = 'gareth@blacksphere.co.nz'
license = 'gplv2+'
inputs = ['logic']
outputs = ['spi']
probes = [
{'id': 'mosi', 'name': 'MOSI',
'desc': 'SPI MOSI line (Master out, slave in)'},
{'id': 'miso', 'name': 'MISO',
'desc': 'SPI MISO line (Master in, slave out)'},
{'id': 'sck', 'name': 'CLK', 'desc': 'SPI clock line'},
{'id': 'cs', 'name': 'CS#', 'desc': 'SPI CS (chip select) line'},
]
options = {
'cs_active_low': ['CS# active low', ACTIVE_LOW],
'clock_polarity': ['Clock polarity', CPOL_0],
'clock_phase': ['Clock phase', CPHA_0],
'bit_order': ['Bit order within the SPI data', MSB_FIRST],
'word_size': ['Word size of SPI data', 8], # 1-64?
}
annotations = [
['Hex', 'SPI data bytes in hex format'],
]
def __init__(self):
self.oldsck = 1
self.bitcount = 0
self.mosidata = 0
self.misodata = 0
self.bytesreceived = 0
self.samplenum = -1
# Set protocol decoder option defaults.
self.cs_active_low = Decoder.options['cs_active_low'][1]
self.clock_polarity = Decoder.options['clock_polarity'][1]
self.clock_phase = Decoder.options['clock_phase'][1]
self.bit_order = Decoder.options['bit_order'][1]
self.word_size = Decoder.options['word_size'][1]
def start(self, metadata):
self.out_proto = self.add(srd.OUTPUT_PROTO, 'spi')
self.out_ann = self.add(srd.OUTPUT_ANN, 'spi')
def report(self):
return 'SPI: %d bytes received' % self.bytesreceived
def decode(self, ss, es, data):
# HACK! At the moment the number of probes is not handled correctly.
# E.g. if an input file (-i foo.sr) has more than two probes enabled.
# for (samplenum, (mosi, sck, x, y, z, a)) in data:
# for (samplenum, (cs, miso, sck, mosi, wp, hold)) in data:
for (samplenum, (cs, miso, sck, mosi, wp, hold)) in data:
self.samplenum += 1 # FIXME
# Sample data on rising SCK edges.
if sck == self.oldsck:
continue
self.oldsck = sck
if sck == 0:
continue
# If this is the first bit, save its sample number.
if self.bitcount == 0:
self.start_sample = samplenum
# Receive MOSI bit into our shift register.
if self.bit_order == MSB_FIRST:
self.mosidata |= mosi << (self.wordsize - 1 - self.bitcount)
else:
self.mosidata |= mosi << self.bitcount
# Receive MISO bit into our shift register.
if self.bit_order == MSB_FIRST:
self.misodata |= miso << (self.wordsize - 1 - self.bitcount)
else:
self.misodata |= miso << self.bitcount
self.bitcount += 1
# Continue to receive if not a byte yet.
if self.bitcount != self.wordsize:
continue
self.put(self.start_sample, self.samplenum, self.out_proto,
['data', self.mosidata, self.misodata])
self.put(self.start_sample, self.samplenum, self.out_ann,
[ANN_HEX, ['MOSI: 0x%02x, MISO: 0x%02x' % (self.mosidata,
self.misodata)]])
# Reset decoder state.
self.mosidata = 0
self.misodata = 0
self.bitcount = 0
# Keep stats for summary.
self.bytesreceived += 1
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