X-Git-Url: https://sigrok.org/gitweb/?p=libsigrokdecode.git;a=blobdiff_plain;f=decoders%2Fguess_bitrate%2Fpd.py;h=462fa8aac33ae6e473be146edfbc92763088685f;hp=1bccc5435dd88c7536a1eb6f8b60a0070855ccc5;hb=6cbba91f23b9f9ace75b4722c9c0776b9211008d;hpb=97b874bd0b6913ed52df1b8aac5e7491479fac9a

diff --git a/decoders/guess_bitrate/pd.py b/decoders/guess_bitrate/pd.py
index 1bccc54..462fa8a 100644
--- a/decoders/guess_bitrate/pd.py
+++ b/decoders/guess_bitrate/pd.py
@@ -30,7 +30,8 @@ class Decoder(srd.Decoder):
     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'},
     )
@@ -42,9 +43,10 @@ class Decoder(srd.Decoder):
         self.put(self.ss_edge, self.samplenum, self.out_ann, data)
 
     def __init__(self):
+        self.reset()
+
+    def reset(self):
         self.ss_edge = None
-        self.first_transition = True
-        self.bitwidth = None
 
     def start(self):
         self.out_ann = self.register(srd.OUTPUT_ANN)
@@ -57,19 +59,21 @@ class Decoder(srd.Decoder):
         if not self.samplerate:
             raise SamplerateError('Cannot decode without samplerate.')
 
+        # Get the first edge on the data line.
+        self.wait({0: 'e'})
+        self.ss_edge = self.samplenum
+
+        # 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:
-            # Wait for any transition/edge on the data line.
             self.wait({0: 'e'})
 
-            # Get the smallest distance between two transitions
-            # and use that to calculate the bitrate/baudrate.
-            if self.first_transition:
-                self.ss_edge = self.samplenum
-                self.first_transition = False
-            else:
-                b = self.samplenum - self.ss_edge
-                if self.bitwidth is 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
+            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