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##
## This file is part of the sigrok project.
##
## Copyright (C) 2010 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
##
class Sample():
def __init__(self, data):
self.data = data
def probe(self, probe):
s = ord(self.data[probe / 8]) & (1 << (probe % 8))
return True if s else False
def sampleiter(data, unitsize):
for i in range(0, len(data), unitsize):
yield(Sample(data[i:i+unitsize]))
class Decoder():
name = 'Transition counter'
longname = '...'
desc = 'Counts rising/falling edges in the signal.'
longdesc = '...'
author = 'Uwe Hermann'
email = 'uwe@hermann-uwe.de'
license = 'gplv2+'
inputs = ['logic']
outputs = ['transitioncounts']
probes = {}
options = {}
def __init__(self, **kwargs):
self.probes = Decoder.probes.copy()
# TODO: Don't hardcode the number of channels.
self.channels = 8
self.lastsample = None
self.oldbit = [0] * self.channels
self.transitions = [0] * self.channels
self.rising = [0] * self.channels
self.falling = [0] * self.channels
def start(self, metadata):
self.unitsize = metadata['unitsize']
def report(self):
pass
def decode(self, data):
"""Counts the low->high and high->low transitions in the specified
channel(s) of the signal."""
# We should accept a list of samples and iterate...
for sample in sampleiter(data['data'], self.unitsize):
# TODO: Eliminate the need for ord().
s = ord(sample.data)
# Optimization: Skip identical samples (no transitions).
if self.lastsample == s:
continue
# Upon the first sample, store the initial values.
if self.lastsample == None:
self.lastsample = s
for i in range(self.channels):
self.oldbit[i] = (self.lastsample & (1 << i)) >> i
# Iterate over all channels/probes in this sample.
# Count rising and falling edges for each channel.
for i in range(self.channels):
curbit = (s & (1 << i)) >> i
# Optimization: Skip identical bits (no transitions).
if self.oldbit[i] == curbit:
continue
elif (self.oldbit[i] == 0 and curbit == 1):
self.rising[i] += 1
elif (self.oldbit[i] == 1 and curbit == 0):
self.falling[i] += 1
self.oldbit[i] = curbit
# Save the current sample as 'lastsample' for the next round.
self.lastsample = s
# Total number of transitions = rising + falling edges.
for i in range(self.channels):
self.transitions[i] = self.rising[i] + self.falling[i]
# TODO: Which output format?
# TODO: How to only output something after the last chunk of data?
outdata = []
for i in range(self.channels):
outdata += [[self.transitions[i], self.rising[i], self.falling[i]]]
sigrok.put(outdata)
# Use psyco (if available) as it results in huge performance improvements.
try:
import psyco
psyco.bind(decode)
except ImportError:
pass
import sigrok
|
