srd: Decoders: Fix/simplify samplenum usage.

[libsigrokdecode.git] / decoders / spi / spi.py

diff --git a/decoders/spi/spi.py b/decoders/spi/spi.py
index 57f55624ffe4c5ed5d27de921c6ada1d6ffc74d0..5e5e74ec5c7123d8a022beb0086e04a7e1f17dc8 100644 (file)
--- a/decoders/spi/spi.py
+++ b/decoders/spi/spi.py
@@ -19,25 +19,13 @@
 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 ##
 
-import sigrokdecode as srd
-
-# Chip-select options
-ACTIVE_LOW = 0
-ACTIVE_HIGH = 1
-
-# Clock polarity options
-CPOL_0 = 0 # Clock is low when inactive
-CPOL_1 = 1 # Clock is high when inactive
+# SPI protocol decoder
 
-# Clock phase options
-CPHA_0 = 0 # Data is valid on the leading clock edge
-CPHA_1 = 1 # Data is valid on the trailing clock edge
-
-# Bit order options
-MSB_FIRST = 0
-LSB_FIRST = 1
+import sigrokdecode as srd
 
 # Key: (CPOL, CPHA). Value: SPI mode.
+# Clock polarity (CPOL) = 0/1: Clock is low/high when inactive.
+# Clock phase (CPHA) = 0/1: Data is valid on the leading/trailing clock edge.
 spi_mode = {
     (0, 0): 0, # Mode 0
     (0, 1): 1, # Mode 1
@@ -54,23 +42,23 @@ class Decoder(srd.Decoder):
     name = 'SPI'
     longname = 'Serial Peripheral Interface'
     desc = '...desc...'
-    longdesc = '...longdesc...'
     license = 'gplv2+'
     inputs = ['logic']
     outputs = ['spi']
     probes = [
-        {'id': 'mosi', 'name': 'MOSI',
-         'desc': 'SPI MOSI line (Master out, slave in)'},
         {'id': 'miso', 'name': 'MISO',
          'desc': 'SPI MISO line (Master in, slave out)'},
+        {'id': 'mosi', 'name': 'MOSI',
+         'desc': 'SPI MOSI line (Master out, slave in)'},
         {'id': 'sck', 'name': 'CLK', 'desc': 'SPI clock line'},
         {'id': 'cs', 'name': 'CS#', 'desc': 'SPI CS (chip select) line'},
     ]
+    optional_probes = [] # TODO
     options = {
-        'cs_polarity': ['CS# polarity', ACTIVE_LOW],
-        'cpol': ['Clock polarity', CPOL_0],
-        'cpha': ['Clock phase', CPHA_0],
-        'bitorder': ['Bit order within the SPI data', MSB_FIRST],
+        'cs_polarity': ['CS# polarity', 'active-low'],
+        'cpol': ['Clock polarity', 0],
+        'cpha': ['Clock phase', 0],
+        'bitorder': ['Bit order within the SPI data', 'msb-first'],
         'wordsize': ['Word size of SPI data', 8], # 1-64?
     }
     annotations = [
@@ -94,13 +82,8 @@ class Decoder(srd.Decoder):
         return 'SPI: %d bytes received' % self.bytesreceived
 
     def decode(self, ss, es, data):
-        # HACK! At the moment the number of probes is not handled correctly.
-        # E.g. if an input file (-i foo.sr) has more than two probes enabled.
-        # for (samplenum, (mosi, sck, x, y, z, a)) in data:
-        # for (samplenum, (cs, miso, sck, mosi, wp, hold)) in data:
-        for (samplenum, (cs, miso, sck, mosi, wp, hold)) in data:
-
-            self.samplenum += 1 # FIXME
+        # TODO: Either MISO or MOSI could be optional. CS# is optional.
+        for (self.samplenum, (miso, mosi, sck, cs)) in data:
 
             # Ignore sample if the clock pin hasn't changed.
             if sck == self.oldsck:
@@ -121,28 +104,30 @@ class Decoder(srd.Decoder):
 
             # If this is the first bit, save its sample number.
             if self.bitcount == 0:
-                self.start_sample = samplenum
-                active_low = (self.options['cs_polarity'] == ACTIVE_LOW)
+                self.start_sample = self.samplenum
+                active_low = (self.options['cs_polarity'] == 'active-low')
                 deasserted = cs if active_low else not cs
                 if deasserted:
                     self.cs_was_deasserted_during_data_word = 1
 
+            ws = self.options['wordsize']
+
             # Receive MOSI bit into our shift register.
-            if self.options['bitorder'] == MSB_FIRST:
-                self.mosidata |= mosi << (self.options['wordsize'] - 1 - self.bitcount)
+            if self.options['bitorder'] == 'msb-first':
+                self.mosidata |= mosi << (ws - 1 - self.bitcount)
             else:
                 self.mosidata |= mosi << self.bitcount
 
             # Receive MISO bit into our shift register.
-            if self.options['bitorder'] == MSB_FIRST:
-                self.misodata |= miso << (self.options['wordsize'] - 1 - self.bitcount)
+            if self.options['bitorder'] == 'msb-first':
+                self.misodata |= miso << (ws - 1 - self.bitcount)
             else:
                 self.misodata |= miso << self.bitcount
 
             self.bitcount += 1
 
-            # Continue to receive if not a byte yet.
-            if self.bitcount != self.options['wordsize']:
+            # Continue to receive if not enough bits were received, yet.
+            if self.bitcount != ws:
                 continue
 
             self.put(self.start_sample, self.samplenum, self.out_proto,