counter: Let user decide how to handle the initial dead_cycles state

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

diff --git a/decoders/counter/pd.py b/decoders/counter/pd.py
index 23cbd9781b5a5618bf95ce1fdf938c8a6f801f5e..27a2be88dc07934f9eed9a33a90ddc121c5d7c70 100644 (file)
--- a/decoders/counter/pd.py
+++ b/decoders/counter/pd.py
@@ -19,8 +19,8 @@
 
 import sigrokdecode as srd
 
-(PIN_DATA, PIN_RESET) = range(2)
-(ROW_EDGE, ROW_WORD, ROW_RESET) = range(3)
+PIN_DATA, PIN_RESET = range(2)
+ROW_EDGE, ROW_WORD, ROW_RESET = range(3)
 
 class Decoder(srd.Decoder):
     api_version = 3
@@ -53,6 +53,11 @@ class Decoder(srd.Decoder):
         {'id': 'divider', 'desc': 'Count divider (word width)', 'default': 0},
         {'id': 'reset_edge', 'desc': 'Edge which clears counters (reset)',
             'default': 'falling', 'values': ('rising', 'falling')},
+        {'id': 'edge_off', 'desc': 'Edge counter value after start/reset', 'default': 0},
+        {'id': 'word_off', 'desc': 'Word counter value after start/reset', 'default': 0},
+        {'id': 'dead_cycles', 'desc': 'Ignore this many edges after reset', 'default': 0},
+        {'id': 'start_with_reset', 'desc': 'Assume decode starts with reset',
+            'default': 'no', 'values': ('no', 'yes')},
     )
 
     def __init__(self):
@@ -86,21 +91,53 @@ class Decoder(srd.Decoder):
             cond_reset = len(condition)
             condition.append({PIN_RESET: opt_edge_map[reset_edge]})
 
-        edge_count = 0
-        word_count = 0
+        edge_count = int(self.options['edge_off'])
+        edge_start = None
+        word_count = int(self.options['word_off'])
+        word_start = None
+
+        if self.options['start_with_reset'] == 'yes':
+            dead_count = int(self.options['dead_cycles'])
+        else:
+            dead_count = 0
+
         while True:
             self.wait(condition)
             now = self.samplenum
 
             if have_reset and self.matched[cond_reset]:
-                edge_count = 0
-                word_count = 0
+                edge_count = int(self.options['edge_off'])
+                edge_start = now
+                word_count = int(self.options['word_off'])
+                word_start = now
                 self.putc(ROW_RESET, now, ['Word reset', 'Reset', 'Rst', 'R'])
+                dead_count = int(self.options['dead_cycles'])
                 continue
 
+            if dead_count:
+                dead_count -= 1
+                edge_start = now
+                word_start = now
+                continue
+
+            # Implementation note: In the absence of a RESET condition
+            # before the first data edge, any arbitrary choice of where
+            # to start the annotation is valid. One may choose to emit a
+            # narrow annotation (where ss=es), or assume that the cycle
+            # which corresponds to the counter value started at sample
+            # number 0. We decided to go with the latter here, to avoid
+            # narrow annotations (see bug #1210). None of this matters in
+            # the presence of a RESET condition in the input stream.
+            if edge_start is None:
+                edge_start = 0
+            if word_start is None:
+                word_start = 0
+
             edge_count += 1
-            self.putc(ROW_EDGE, now, ["{:d}".format(edge_count)])
+            self.putc(ROW_EDGE, edge_start, ["{:d}".format(edge_count)])
+            edge_start = now
 
             if divider and (edge_count % divider) == 0:
                 word_count += 1
-                self.putc(ROW_WORD, now, ["{:d}".format(word_count)])
+                self.putc(ROW_WORD, word_start, ["{:d}".format(word_count)])
+                word_start = now