scripts/transitioncounter.py

   1 ##
   2 ## This file is part of the sigrok project.
   3 ##
   4 ## Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
   5 ##
   6 ## This program is free software; you can redistribute it and/or modify
   7 ## it under the terms of the GNU General Public License as published by
   8 ## the Free Software Foundation; either version 2 of the License, or
   9 ## (at your option) any later version.
  10 ##
  11 ## This program is distributed in the hope that it will be useful,
  12 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ## GNU General Public License for more details.
  15 ##
  16 ## You should have received a copy of the GNU General Public License
  17 ## along with this program; if not, write to the Free Software
  18 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19 ##
  20
  21 def sigrokdecode_count_transitions(inbuf):
  22         """Counts the low->high and high->low transitions in the specified
  23            channel(s) of the signal."""
  24
  25         outbuf = ''
  26
  27         # FIXME: Get the data in the correct format in the first place.
  28         inbuf = [ord(x) for x in inbuf]
  29
  30         # TODO: Don't hardcode the number of channels.
  31         channels = 8
  32
  33         oldbit = [0] * channels
  34         transitions = [0] * channels
  35         rising = [0] * channels
  36         falling = [0] * channels
  37
  38         # print len(inbuf)
  39         # print type(inbuf)
  40
  41         # Presets...
  42         oldbyte = inbuf[0]
  43         for i in range(channels):
  44                 oldbit[i] = (oldbyte & (1 << i)) >> i
  45
  46         # Loop over all samples.
  47         # TODO: Handle LAs with more/less than 8 channels.
  48         for s in inbuf:
  49                 # Optimization: Skip identical bytes (no transitions).
  50                 if oldbyte == s:
  51                         continue
  52                 for i in range(channels):
  53                         curbit = (s & (1 << i)) >> i
  54                         # Optimization: Skip identical bits (no transitions).
  55                         if oldbit[i] == curbit:
  56                                 continue
  57                         elif (oldbit[i] == 0 and curbit == 1):
  58                                 rising[i] += 1
  59                         elif (oldbit[i] == 1 and curbit == 0):
  60                                 falling[i] += 1
  61                         oldbit[i] = curbit
  62
  63         # Total number of transitions is the sum of rising and falling edges.
  64         for i in range(channels):
  65                 transitions[i] = rising[i] + falling[i]
  66
  67         outbuf += "Rising edges:  "
  68         for i in range(channels):
  69                 outbuf += str(rising[i]) + " "
  70         outbuf += "\nFalling edges: "
  71         for i in range(channels):
  72                 outbuf += str(falling[i]) + " "
  73         outbuf += "\nTransitions:   "
  74         for i in range(channels):
  75                 outbuf += str(transitions[i]) + " "
  76         outbuf += "\n"
  77
  78         return outbuf
  79
  80 # Use psyco (if available) as it results in huge performance improvements.
  81 try:
  82         import psyco
  83         psyco.bind(sigrokdecode_count_transitions)
  84 except ImportError:
  85         pass
  86