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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
##
def decode(inbuf):
"""Counts the low->high and high->low transitions in the specified
channel(s) of the signal."""
outbuf = ''
# FIXME: Get the data in the correct format in the first place.
inbuf = [ord(x) for x in inbuf]
# TODO: Don't hardcode the number of channels.
channels = 8
oldbit = [0] * channels
transitions = [0] * channels
rising = [0] * channels
falling = [0] * channels
# Initial values.
oldbyte = inbuf[0]
for i in range(channels):
oldbit[i] = (oldbyte & (1 << i)) >> i
# Loop over all samples.
# TODO: Handle LAs with more/less than 8 channels.
for s in inbuf:
# Optimization: Skip identical bytes (no transitions).
if oldbyte == s:
continue
for i in range(channels):
curbit = (s & (1 << i)) >> i
# Optimization: Skip identical bits (no transitions).
if oldbit[i] == curbit:
continue
elif (oldbit[i] == 0 and curbit == 1):
rising[i] += 1
elif (oldbit[i] == 1 and curbit == 0):
falling[i] += 1
oldbit[i] = curbit
oldbyte = s
# Total number of transitions is the sum of rising and falling edges.
for i in range(channels):
transitions[i] = rising[i] + falling[i]
outbuf += "Rising edges: "
for i in range(channels):
outbuf += str(rising[i]) + " "
outbuf += "\nFalling edges: "
for i in range(channels):
outbuf += str(falling[i]) + " "
outbuf += "\nTransitions: "
for i in range(channels):
outbuf += str(transitions[i]) + " "
outbuf += "\n"
return outbuf
def register():
return {
'id': 'transitioncounter',
'name': 'Transition counter',
'longname': '...',
'desc': 'Counts rising/falling edges in the signal.',
'longdesc': '...',
'author': 'Uwe Hermann',
'email': 'uwe@hermann-uwe.de',
'license': 'gplv2+',
'in': ['logic'],
'out': ['transitioncounts'],
'probes': [
# All probes.
],
'options': {
# No options so far.
},
# 'start': start,
# 'report': report,
}
# Use psyco (if available) as it results in huge performance improvements.
try:
import psyco
psyco.bind(decode)
except ImportError:
pass
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