usb_signalling: Refactor/simplify bitrate/bitwidth handling.

[libsigrokdecode.git] / decoders / usb_signalling / pd.py

diff --git a/decoders/usb_signalling/pd.py b/decoders/usb_signalling/pd.py
index e6b729919a1a9161dfe4e92ed4d1a9cac3f25a4c..70ada3767af7c10fd140f78246c416bf709a4d7c 100644 (file)
--- a/decoders/usb_signalling/pd.py
+++ b/decoders/usb_signalling/pd.py
@@ -1,8 +1,8 @@
 ##
-## This file is part of the sigrok project.
+## This file is part of the libsigrokdecode project.
 ##
 ## Copyright (C) 2011 Gareth McMullin <gareth@blacksphere.co.nz>
-## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
+## Copyright (C) 2012-2013 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
@@ -40,6 +40,11 @@ symbols_fs = {
         (1, 1): 'SE1',
 }
 
+bitrates = {
+    'low-speed': 1500000,   # 1.5Mb/s (+/- 1.5%)
+    'full-speed': 12000000, # 12Mb/s (+/- 0.25%)
+}
+
 class Decoder(srd.Decoder):
     api_version = 1
     id = 'usb_signalling'
@@ -67,16 +72,25 @@ class Decoder(srd.Decoder):
         self.scount = 0
         self.packet = ''
         self.syms = []
+        self.bitrate = None
+        self.bitwidth = None
         self.oldpins = None
 
     def start(self, metadata):
-        self.samplerate = metadata['samplerate']
         self.out_proto = self.add(srd.OUTPUT_PROTO, 'usb_signalling')
         self.out_ann = self.add(srd.OUTPUT_ANN, 'usb_signalling')
+        self.bitrate = bitrates[self.options['signalling']]
+        self.bitwidth = float(metadata['samplerate']) / float(self.bitrate)
 
     def report(self):
         pass
 
+    def putp(self, data):
+        self.put(self.samplenum, self.samplenum, self.out_proto, data)
+
+    def putx(self, data):
+        self.put(self.samplenum, self.samplenum, self.out_ann, data)
+
     def decode(self, ss, es, data):
         for (self.samplenum, pins) in data:
 
@@ -95,8 +109,8 @@ class Decoder(srd.Decoder):
             elif self.options['signalling'] == 'full-speed':
                 sym = symbols_fs[dp, dm]
 
-            self.put(0, 0, self.out_ann, [0, [sym]])
-            self.put(0, 0, self.out_proto, ['SYM', sym])
+            self.putx([0, [sym]])
+            self.putp(['SYM', sym])
 
             # Wait for a symbol change (i.e., change in D+/D- lines).
             if sym == self.sym:
@@ -105,33 +119,28 @@ class Decoder(srd.Decoder):
             ## # Debug code:
             ## self.syms.append(sym + ' ')
             ## if len(self.syms) == 16:
-            ##     self.put(0, 0, self.out_ann, [0, [''.join(self.syms)]])
+            ##     self.putx([0, [''.join(self.syms)]])
             ##     self.syms = []
             # continue
 
             # How many bits since the last transition?
             if self.packet != '' or self.sym != 'J':
-                if self.options['signalling'] == 'low-speed':
-                    bitrate = 1500000 # 1.5Mb/s (+/- 1.5%)
-                elif self.options['signalling'] == 'full-speed':
-                    bitrate = 12000000 # 12Mb/s (+/- 0.25%)
-                bitcount = int((self.scount - 1) * bitrate / self.samplerate)
+                bitcount = int((self.scount - 1) / self.bitwidth)
             else:
                 bitcount = 0
 
             if self.sym == 'SE0':
                 if bitcount == 1:
                     # End-Of-Packet (EOP)
-                    # self.put(0, 0, self.out_ann,
-                    #          [0, [packet_decode(self.packet), self.packet]])
+                    # self.putx([0, [packet_decode(self.packet), self.packet]])
                     if self.packet != '': # FIXME?
-                        self.put(0, 0, self.out_ann, [0, ['PACKET: %s' % self.packet]])
-                        self.put(0, 0, self.out_proto, ['PACKET', self.packet])
+                        self.putx([0, ['PACKET: %s' % self.packet]])
+                        self.putp(['PACKET', self.packet])
                 else:
                     # Longer than EOP, assume reset.
-                    self.put(0, 0, self.out_ann, [0, ['RESET']])
-                    self.put(0, 0, self.out_proto, ['RESET', None])
-                # self.put(0, 0, self.out_ann, [0, [self.packet]])
+                    self.putx([0, ['RESET']])
+                    self.putp(['RESET', None])
+                # self.putx([0, [self.packet]])
                 self.scount = 0
                 self.sym = sym
                 self.packet = ''
@@ -144,8 +153,8 @@ class Decoder(srd.Decoder):
             if bitcount < 6 and sym != 'SE0':
                 self.packet += '0'
             elif bitcount > 6:
-                self.put(0, 0, self.out_ann, [0, ['BIT STUFF ERROR']])
-                self.put(0, 0, self.out_proto, ['BIT STUFF ERROR', None])
+                self.putx([0, ['BIT STUFF ERROR']])
+                self.putp(['BIT STUFF ERROR', None])
 
             self.scount = 0
             self.sym = sym