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##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2013-2016 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, see <http://www.gnu.org/licenses/>.
##
import sigrokdecode as srd
from common.srdhelper import bitpack
'''
OUTPUT_PYTHON format:
Packet:
[<ptype>, <pdata>]
<ptype>, <pdata>
- 'ITEM', [<item>, <itembitsize>]
- 'WORD', [<word>, <wordbitsize>, <worditemcount>]
<item>:
- A single item (a number). It can be of arbitrary size. The max. number
of bits in this item is specified in <itembitsize>.
<itembitsize>:
- The size of an item (in bits). For a 4-bit parallel bus this is 4,
for a 16-bit parallel bus this is 16, and so on.
<word>:
- A single word (a number). It can be of arbitrary size. The max. number
of bits in this word is specified in <wordbitsize>. The (exact) number
of items in this word is specified in <worditemcount>.
<wordbitsize>:
- The size of a word (in bits). For a 2-item word with 8-bit items
<wordbitsize> is 16, for a 3-item word with 4-bit items <wordbitsize>
is 12, and so on.
<worditemcount>:
- The size of a word (in number of items). For a 4-item word (no matter
how many bits each item consists of) <worditemcount> is 4, for a 7-item
word <worditemcount> is 7, and so on.
'''
NUM_CHANNELS = 8
class Pin:
CLOCK = 0
DATA_0 = CLOCK + 1
DATA_N = DATA_0 + NUM_CHANNELS
class Ann:
ITEM, WORD = range(2)
class ChannelError(Exception):
pass
class Decoder(srd.Decoder):
api_version = 3
id = 'parallel'
name = 'Parallel'
longname = 'Parallel sync bus'
desc = 'Generic parallel synchronous bus.'
license = 'gplv2+'
inputs = ['logic']
outputs = ['parallel']
tags = ['Util']
optional_channels = tuple(
[{'id': 'clk', 'name': 'CLK', 'desc': 'Clock line'}] +
[
{'id': 'd%d' % i, 'name': 'D%d' % i, 'desc': 'Data line %d' % i}
for i in range(NUM_CHANNELS)
]
)
options = (
{'id': 'clock_edge', 'desc': 'Clock edge to sample on',
'default': 'rising', 'values': ('rising', 'falling')},
{'id': 'wordsize', 'desc': 'Data wordsize (# bus cycles)',
'default': 0},
{'id': 'endianness', 'desc': 'Data endianness',
'default': 'little', 'values': ('little', 'big')},
)
annotations = (
('item', 'Item'),
('word', 'Word'),
)
annotation_rows = (
('items', 'Items', (Ann.ITEM,)),
('words', 'Words', (Ann.WORD,)),
)
def __init__(self):
self.reset()
def reset(self):
self.items = []
self.saved_item = None
self.ss_item = self.es_item = None
self.saved_word = None
self.ss_word = self.es_word = None
self.first = True
def start(self):
self.out_python = self.register(srd.OUTPUT_PYTHON)
self.out_ann = self.register(srd.OUTPUT_ANN)
def putpb(self, data):
self.put(self.ss_item, self.es_item, self.out_python, data)
def putb(self, data):
self.put(self.ss_item, self.es_item, self.out_ann, data)
def putpw(self, data):
self.put(self.ss_word, self.es_word, self.out_python, data)
def putw(self, data):
self.put(self.ss_word, self.es_word, self.out_ann, data)
def handle_bits(self, item, used_pins):
# If a word was previously accumulated, then emit its annotation
# now after its end samplenumber became available.
if self.saved_word is not None:
if self.options['wordsize'] > 0:
self.es_word = self.samplenum
self.putw([Ann.WORD, [self.fmt_word.format(self.saved_word)]])
self.putpw(['WORD', self.saved_word])
self.saved_word = None
# Defer annotations for individual items until the next sample
# is taken, and the previous sample's end samplenumber has
# become available.
if self.first:
# Save the start sample and item for later (no output yet).
self.ss_item = self.samplenum
self.first = False
self.saved_item = item
else:
# Output the saved item (from the last CLK edge to the current).
self.es_item = self.samplenum
self.putpb(['ITEM', self.saved_item])
self.putb([Ann.ITEM, [self.fmt_item.format(self.saved_item)]])
self.ss_item = self.samplenum
self.saved_item = item
# Get as many items as the configured wordsize specifies.
if not self.items:
self.ss_word = self.samplenum
self.items.append(item)
ws = self.options['wordsize']
if len(self.items) < ws:
return
# Collect words and prepare annotation details, but defer emission
# until the end samplenumber becomes available.
endian = self.options['endianness']
if endian == 'big':
self.items.reverse()
word = sum([self.items[i] << (i * used_pins) for i in range(ws)])
self.saved_word = word
self.items = []
def decode(self):
# Determine which (optional) channels have input data. Insist in
# a non-empty input data set. Cope with sparse connection maps.
# Store enough state to later "compress" sampled input data.
data_indices = [
idx if self.has_channel(idx) else None
for idx in range(Pin.DATA_0, Pin.DATA_N)
]
has_data = [idx for idx in data_indices if idx is not None]
if not has_data:
raise ChannelError('Need at least one data channel.')
max_connected = max(has_data)
# Pre-determine which input data to strip off, the width of
# individual items and multiplexed words, as well as format
# strings here. This simplifies call sites which run in tight
# loops later.
upper_data_bound = max_connected + 1
num_item_bits = upper_data_bound - Pin.DATA_0
num_word_items = self.options['wordsize']
num_word_bits = num_item_bits * num_word_items
num_digits = (num_item_bits + 4 - 1) // 4
self.fmt_item = "{{:0{}x}}".format(num_digits)
num_digits = (num_word_bits + 4 - 1) // 4
self.fmt_word = "{{:0{}x}}".format(num_digits)
# Determine .wait() conditions, depending on the presence of a
# clock signal. Either inspect samples on the configured edge of
# the clock, or inspect samples upon ANY edge of ANY of the pins
# which provide input data.
has_clock = self.has_channel(Pin.CLOCK)
if has_clock:
edge = self.options['clock_edge'][0]
conds = [{Pin.CLOCK: edge}]
else:
conds = [{idx: 'e'} for idx in has_data]
# Keep processing the input stream. Assume "always zero" for
# not-connected input lines. Pass data bits (all inputs except
# clock) to the handle_bits() method.
while True:
pins = self.wait(conds)
data_bits = [0 if idx is None else pins[idx] for idx in data_indices]
data_bits = data_bits[:num_item_bits]
item = bitpack(data_bits)
self.handle_bits(item, num_item_bits)
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