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add support for decode spi dual/quad
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mfont-bz17 committed Apr 11, 2023
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30 changes: 30 additions & 0 deletions spi_dual_quad/__init__.py
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##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2023 Marc Font Freixa <[email protected]>
##
## 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, see <http://www.gnu.org/licenses/>.
##

'''
The SPI Dual/Quad (Serial Peripheral Interface) protocol decoder supports synchronous
SPI(-like) protocols with a clock line, a SIO0, SIO1, SIO2, SIO3 lines for data
transfer in two directions, and an optional CS# pin.
If CS# is supplied, data is only decoded when CS# is asserted (clock
transitions where CS# is not asserted are ignored). If CS# is not supplied,
data is decoded on every clock transition (depending on SPI mode).
'''

from .pd import Decoder
356 changes: 356 additions & 0 deletions spi_dual_quad/pd.py
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##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2023 Marc Font Freixa <[email protected]>
##
## 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, see <http://www.gnu.org/licenses/>.
##

import sigrokdecode as srd
from collections import namedtuple

Data = namedtuple('Data', ['ss', 'es', 'val'])

'''
OUTPUT_PYTHON format:
Packet:
[<ptype>, <data1>, <data2>]
<ptype>:
- 'DATA': <data1> contains the spi 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': <data1>/<data2> contain a list of bit values in this sio0/sio1/sio2/sio3 data
item, and for each of those also their respective start-/endsample numbers.
- 'CS-CHANGE': <data1> is the old CS# pin value, <data2> 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 <data1> = None and <data2> being the
initial state of the CS# pin or None if the chip select pin is not supplied.
- 'TRANSFER': <data1> contain a list of Data() namedtuples for each
byte transferred during this block of CS# asserted time. Each Data() has
fields ss, es, and val.
Examples:
['CS-CHANGE', None, 1]
['CS-CHANGE', 1, 0]
['DATA', 0xff]
['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]
['DATA', 0xa8]
['DATA', 0x55]
['CS-CHANGE', 0, 1]
['TRANSFER', [Data(ss=80, es=96, val=0xff), ...]]
'''

# 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
}

ann_spi_data, ann_spi_sio0, ann_spi_sio1, ann_spi_sio2, ann_spi_sio3, ann_spi_other, ann_spi_xfer = range(7)

class ChannelError(Exception):
pass

class Decoder(srd.Decoder):
api_version = 3
id = 'spi-dual-quad'
name = 'SPI Dual/Quad'
longname = 'Dual/Quad Serial Peripheral Interface'
desc = 'Full-duplex, synchronous, serial bus.'
license = 'gplv2+'
inputs = ['logic']
outputs = ['spi']
tags = ['Embedded/industrial']
channels = (
{'id': 'clk', 'name': 'CLK', 'desc': 'Clock'},
{'id': 'sio0', 'name': 'SIO0', 'desc': 'SPI Input/Output 0'},
{'id': 'sio1', 'name': 'SIO1', 'desc': 'SPI Input/Output 1'},
)
optional_channels = (
{'id': 'sio2', 'name': 'SIO2', 'desc': 'SPI Input/Output 2'},
{'id': 'sio3', 'name': 'SIO3', 'desc': 'SPI Input/Output 3'},
{'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 = (
('spi-data', 'SPI data'),
('sio0-bit', 'SIO0 bit'),
('sio1-bit', 'SIO1 bit'),
('sio2-bit', 'SIO2 bit'),
('sio3-bit', 'SIO3 bit'),
('warning', 'Warning'),
('spi-transfer', 'SPI transfer'),
)
annotation_rows = (
('sio0-bits', 'SIO0 bits', (ann_spi_sio0,)),
('sio1-bits', 'SIO1 bits', (ann_spi_sio1,)),
('sio2-bits', 'SIO2 bits', (ann_spi_sio2,)),
('sio3-bits', 'SIO3 bits', (ann_spi_sio3,)),
('spi-data-vals', 'SPI data', (ann_spi_data,)),
('spi-transfers', 'SPI transfers', (ann_spi_xfer,)),
('other', 'Other', (ann_spi_other,)),
)
binary = (
('spi-data', 'SPI Data'),
)

def __init__(self):
self.reset()

def reset(self):
self.samplerate = None
self.bitcount = 0
self.spidata = 0
self.sio0bits = []
self.sio1bits = []
self.sio2bits = []
self.sio3bits = []
self.spibytes = []
self.ss_block = -1
self.ss_transfer = -1
self.cs_was_deasserted = False
self.have_cs = None
self.is_quad = None

def start(self):
self.out_python = self.register(srd.OUTPUT_PYTHON)
self.out_ann = self.register(srd.OUTPUT_ANN)
self.out_binary = self.register(srd.OUTPUT_BINARY)
self.out_bitrate = self.register(srd.OUTPUT_META,
meta=(int, 'Bitrate', 'Bitrate during transfers'))
self.bw = (self.options['wordsize'] + 7) // 8

def metadata(self, key, value):
if key == srd.SRD_CONF_SAMPLERATE:
self.samplerate = value

def putw(self, data):
self.put(self.ss_block, self.samplenum, self.out_ann, data)

def putdata(self):
# Pass sio0/sio1/sio2/sio3 bits and then data to the next PD up the stack.
data = self.spidata
sio0_bits = self.sio0bits
sio1_bits = self.sio1bits
sio2_bits = self.sio2bits
sio3_bits = self.sio3bits

ss, es = self.sio0bits[-1][1], self.sio0bits[0][2]
bdata = data.to_bytes(self.bw, byteorder='big')
self.put(ss, es, self.out_binary, [0, bdata])
if self.is_quad:
self.put(ss, es, self.out_python, ['BITS', sio3_bits, sio2_bits, sio1_bits, sio0_bits])
else:
self.put(ss, es, self.out_python, ['BITS', sio1_bits, sio0_bits])
self.put(ss, es, self.out_python, ['DATA', data])

self.spibytes.append(Data(ss=ss, es=es, val=data))

# Bit annotations.
for bit in self.sio0bits:
self.put(bit[1], bit[2], self.out_ann, [ann_spi_sio0, ['%d' % bit[0]]])
for bit in self.sio1bits:
self.put(bit[1], bit[2], self.out_ann, [ann_spi_sio1, ['%d' % bit[0]]])

if self.is_quad:
for bit in self.sio2bits:
self.put(bit[1], bit[2], self.out_ann, [ann_spi_sio2, ['%d' % bit[0]]])
for bit in self.sio3bits:
self.put(bit[1], bit[2], self.out_ann, [ann_spi_sio3, ['%d' % bit[0]]])

# Dataword annotations.
self.put(ss, es, self.out_ann, [ann_spi_data, ['%02X' % self.spidata]])

def reset_decoder_state(self):
self.spidata = 0
self.sio0bits = []
self.sio1bits = []
self.sio2bits = []
self.sio3bits = []
self.bitcount = 0

def cs_asserted(self, cs):
active_low = (self.options['cs_polarity'] == 'active-low')
return (cs == 0) if active_low else (cs == 1)

def handle_bit(self, sio0, sio1, sio2, sio3, 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 = \
not self.cs_asserted(cs) if self.have_cs else False

ws = self.options['wordsize']
bo = self.options['bitorder']

if self.is_quad:
# Quad SPI SIO0 bits 4,0
# Quad SPI SIO1 bits 5,1
# Quad SPI SIO2 bits 6,2
# Quad SPI SIO3 bits 7,3
if bo == 'msb-first':
self.spidata |= sio3 << (ws - 1 - self.bitcount)
self.spidata |= sio2 << (ws - 1 - self.bitcount - 1)
self.spidata |= sio1 << (ws - 1 - self.bitcount - 2)
self.spidata |= sio0 << (ws - 1 - self.bitcount - 3)
else:
self.spidata |= sio3 << self.bitcount
self.spidata |= sio2 << (self.bitcount + 1)
self.spidata |= sio1 << (self.bitcount + 2)
self.spidata |= sio0 << (self.bitcount + 3)
else:
# Dual SPI SIO0 bits 6,4,2,0
# Dual SPI SIO1 bits 7,5,3,1
if bo == 'msb-first':
self.spidata |= sio1 << (ws - 1 - self.bitcount)
self.spidata |= sio0 << (ws - 1 - self.bitcount - 1)
else:
self.spidata |= sio1 << self.bitcount
self.spidata |= sio0 << (self.bitcount + 1)

# Guesstimate the endsample for this bit (can be overridden below).
es = self.samplenum
if self.bitcount > 0:
es += self.samplenum - self.sio0bits[0][1]

self.sio0bits.insert(0, [sio0, self.samplenum, es])
self.sio1bits.insert(0, [sio1, self.samplenum, es])
if self.is_quad:
self.sio2bits.insert(0, [sio2, self.samplenum, es])
self.sio3bits.insert(0, [sio3, self.samplenum, es])

if self.bitcount > 0:
self.sio0bits[1][2] = self.samplenum
self.sio1bits[1][2] = self.samplenum
if self.is_quad:
self.sio2bits[1][2] = self.samplenum
self.sio3bits[1][2] = self.samplenum

if self.is_quad:
self.bitcount += 4
else:
self.bitcount += 2

# Continue to receive if not enough bits were received, yet.
if self.bitcount != ws:
return

self.putdata()

# Meta bitrate.
if self.samplerate:
elapsed = 1 / float(self.samplerate)
elapsed *= (self.samplenum - self.ss_block + 1)
bitrate = int(1 / elapsed * ws)
self.put(self.ss_block, self.samplenum, self.out_bitrate, bitrate)

if self.have_cs and self.cs_was_deasserted:
self.putw([ann_spi_other, ['CS# was deasserted during this data word!']])

self.reset_decoder_state()

def find_clk_edge(self, sio0, sio1, sio2, sio3, clk, cs, first):
if self.have_cs and (first or self.matched[self.have_cs]):
# Send all CS# pin value changes.
oldcs = None if first else 1 - cs
self.put(self.samplenum, self.samplenum, self.out_python,
['CS-CHANGE', oldcs, cs])

if self.cs_asserted(cs):
self.ss_transfer = self.samplenum
self.spibytes = []
elif self.ss_transfer != -1:
self.put(self.ss_transfer, self.samplenum, self.out_ann,
[ann_spi_xfer, [' '.join(format(x.val, '02X') for x in self.spibytes)]])
self.put(self.ss_transfer, self.samplenum, self.out_python,
['TRANSFER', self.spibytes])

# Reset decoder state when CS# changes (and the CS# pin is used).
self.reset_decoder_state()

# We only care about samples if CS# is asserted.
if self.have_cs and not self.cs_asserted(cs):
return

# Ignore sample if the clock pin hasn't changed.
if first or not self.matched[0]:
return

# 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(sio0, sio1, sio2, sio3, clk, cs)

def decode(self):
# The CLK input is mandatory. SIO0 and SIO1 are mandatory for Dual SPI.
if not self.has_channel(0) and not self.has_channel(1) and not self.has_channel(2):
raise ChannelError('For Dual SPI SIO0 and SIO1 are pins required.')
# The CLK input is mandatory. SIO3 and SIO4 are mandatory for Quad SPI.
if (self.has_channel(3) and not self.has_channel(4)) or (self.has_channel(4) and not self.has_channel(3)):
raise ChannelError('For Quad SPI SIO2 and SIO3 are pins required.')

# Mark that SPI is Quad
self.is_quad = self.has_channel(3) and self.has_channel(4)
self.have_cs = self.has_channel(5)
if not self.have_cs:
self.put(0, 0, self.out_python, ['CS-CHANGE', None, None])

# We want all CLK changes. We want all CS changes if CS is used.
# Map 'have_cs' from boolean to an integer index. This simplifies
# evaluation in other locations.
wait_cond = [{0: 'e'}]
if self.have_cs:
self.have_cs = len(wait_cond)
wait_cond.append({5: 'e'})

# "Pixel compatibility" with the v2 implementation. Grab and
# process the very first sample before checking for edges. The
# previous implementation did this by seeding old values with
# None, which led to an immediate "change" in comparison.
(clk, sio0, sio1, sio2, sio3, cs) = self.wait({})
self.find_clk_edge(sio0, sio1, sio2, sio3, clk, cs, True)

while True:
(clk, sio0, sio1, sio2, sio3, cs) = self.wait(wait_cond)
self.find_clk_edge(sio0, sio1, sio2, sio3, clk, cs, False)

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