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         # TODO: Don't hardcode the number of channels.
  28         channels = 8
  29
  30         oldbit = [0] * channels
  31         transitions = [0] * channels
  32         rising = [0] * channels
  33         falling = [0] * channels
  34
  35         # print len(inbuf)
  36         # print type(inbuf)
  37
  38         # Presets...
  39         s = ord(inbuf[0])
  40         for i in xrange(channels):
  41                 curbit = (s & (1 << i) != 0)
  42                 oldbit[i] = curbit
  43
  44         # Loop over all samples.
  45         # TODO: Handle LAs with more/less than 8 channels.
  46         for s in inbuf:
  47                 s = ord(s) # FIXME
  48                 for i in xrange(channels):
  49                         curbit = (s & (1 << i) != 0)
  50                         if (oldbit[i] == 0 and curbit == 1):
  51                                 rising[i] += 1
  52                         elif (oldbit[i] == 1 and curbit == 0):
  53                                 falling[i] += 1
  54                         oldbit[i] = curbit
  55
  56         # Total number of transitions is the sum of rising and falling edges.
  57         for i in xrange(channels):
  58                 transitions[i] = rising[i] + falling[i]
  59
  60         outbuf += "Rising edges:  "
  61         for i in xrange(channels):
  62                 outbuf += str(rising[i]) + " "
  63         outbuf += "\nFalling edges: "
  64         for i in xrange(channels):
  65                 outbuf += str(falling[i]) + " "
  66         outbuf += "\nTransitions:   "
  67         for i in xrange(channels):
  68                 outbuf += str(transitions[i]) + " "
  69         outbuf += "\n"
  70
  71         return outbuf
  72