X-Git-Url: https://sigrok.org/gitweb/?p=libsigrokdecode.git;a=blobdiff_plain;f=decoders%2Fguess_bitrate%2Fpd.py;h=462fa8aac33ae6e473be146edfbc92763088685f;hp=d2d7c39faec29385a6c04f9a24de680e71e57268;hb=6cbba91f23b9f9ace75b4722c9c0776b9211008d;hpb=6a15597a7b3f901b566b7bfc8c484a14e0fb6a11

diff --git a/decoders/guess_bitrate/pd.py b/decoders/guess_bitrate/pd.py
index d2d7c39..462fa8a 100644
--- a/decoders/guess_bitrate/pd.py
+++ b/decoders/guess_bitrate/pd.py
@@ -1,7 +1,7 @@
 ##
 ## This file is part of the libsigrokdecode project.
 ##
-## Copyright (C) 2013 Uwe Hermann <uwe@hermann-uwe.de>
+## 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
@@ -14,21 +14,24 @@
 ## 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
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
 ##
 
 import sigrokdecode as srd
 
+class SamplerateError(Exception):
+    pass
+
 class Decoder(srd.Decoder):
-    api_version = 1
+    api_version = 3
     id = 'guess_bitrate'
     name = 'Guess bitrate'
     longname = 'Guess bitrate/baudrate'
     desc = 'Guess the bitrate/baudrate of a UART (or other) protocol.'
     license = 'gplv2+'
     inputs = ['logic']
-    outputs = ['guess_bitrate']
+    outputs = []
+    tags = ['Clock/timing', 'Util']
     channels = (
         {'id': 'data', 'name': 'Data', 'desc': 'Data line'},
     )
@@ -39,48 +42,38 @@ class Decoder(srd.Decoder):
     def putx(self, data):
         self.put(self.ss_edge, self.samplenum, self.out_ann, data)
 
-    def __init__(self, **kwargs):
-        self.olddata = None
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
         self.ss_edge = None
-        self.first_transition = True
-        self.bitwidth = None
 
     def start(self):
-        # self.out_python = self.register(srd.OUTPUT_PYTHON)
         self.out_ann = self.register(srd.OUTPUT_ANN)
 
     def metadata(self, key, value):
         if key == srd.SRD_CONF_SAMPLERATE:
-            self.samplerate = value;
-
-    def decode(self, ss, es, data):
-        if self.samplerate is None:
-            raise Exception("Cannot decode without samplerate.")
-        for (self.samplenum, pins) in data:
-
-            data = pins[0]
-
-            # Wait for any transition on the data line.
-            if data == self.olddata:
-                continue
+            self.samplerate = value
 
-            # Initialize first self.olddata with the first sample value.
-            if self.olddata == None:
-                self.olddata = data
-                continue
+    def decode(self):
+        if not self.samplerate:
+            raise SamplerateError('Cannot decode without samplerate.')
 
-            # Get the smallest distance between two transitions
-            # and use that to calculate the bitrate/baudrate.
-            if self.first_transition == True:
-                self.ss_edge = self.samplenum
-                self.first_transition = False
-            else:
-                b = self.samplenum - self.ss_edge
-                if self.bitwidth == None or b < self.bitwidth:
-                    self.bitwidth = b
-                    bitrate = int(float(self.samplerate) / float(b))
-                    self.putx([0, ['%d' % bitrate]])
-                self.ss_edge = self.samplenum
+        # Get the first edge on the data line.
+        self.wait({0: 'e'})
+        self.ss_edge = self.samplenum
 
-            self.olddata = data
+        # Get any subsequent edge on the data line. Get the smallest
+        # distance between any two transitions, assuming it corresponds
+        # to one bit time of the respective bitrate of the input stream.
+        # This heuristics keeps getting better for longer captures.
+        bitwidth = None
+        while True:
+            self.wait({0: 'e'})
 
+            b = self.samplenum - self.ss_edge
+            if bitwidth is None or b < bitwidth:
+                bitwidth = b
+                bitrate = int(float(self.samplerate) / float(b))
+                self.putx([0, ['%d' % bitrate]])
+            self.ss_edge = self.samplenum