All PDs: Only import the 'Decoder' object.

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

diff --git a/decoders/spi/pd.py b/decoders/spi/pd.py
index 1ddb119c2729f1c2ff15972db887fc4482e8f15d..97d5571c066a3d8ec6664de9ef04cc766b4d756b 100644 (file)
--- a/decoders/spi/pd.py
+++ b/decoders/spi/pd.py
@@ -28,11 +28,11 @@ Packet:
 [<ptype>, <data1>, <data2>]
 
 <ptype>:
- - 'DATA': <data1> contains the MISO data, <data2> contains the MOSI data.
+ - 'DATA': <data1> contains the MOSI data, <data2> contains the MISO data.
    The data is _usually_ 8 bits (but can also be fewer or more bits).
    Both data items are Python numbers (not strings), or None if the respective
    channel was not supplied.
- - 'BITS': <data1>/<data2> contain a list of bit values in this MISO/MOSI data
+ - 'BITS': <data1>/<data2> contain a list of bit values in this MOSI/MISO data
    item, and for each of those also their respective start-/endsample numbers.
  - 'CS CHANGE': <data1> is the old CS# pin value, <data2> is the new value.
    Both data items are Python numbers (0/1), not strings.
@@ -60,6 +60,12 @@ spi_mode = {
     (1, 1): 3, # Mode 3
 }
 
+class SamplerateError(Exception):
+    pass
+
+class ChannelError(Exception):
+    pass
+
 class Decoder(srd.Decoder):
     api_version = 2
     id = 'spi'
@@ -258,8 +264,8 @@ class Decoder(srd.Decoder):
         self.handle_bit(miso, mosi, clk, cs)
 
     def decode(self, ss, es, data):
-        if self.samplerate is None:
-            raise Exception("Cannot decode without samplerate.")
+        if not self.samplerate:
+            raise SamplerateError('Cannot decode without samplerate.')
         # Either MISO or MOSI can be omitted (but not both). CS# is optional.
         for (self.samplenum, pins) in data:
 
@@ -273,7 +279,6 @@ class Decoder(srd.Decoder):
 
             # Either MISO or MOSI (but not both) can be omitted.
             if not (self.have_miso or self.have_mosi):
-                raise Exception('Either MISO or MOSI (or both) pins required.')
+                raise ChannelError('Either MISO or MOSI (or both) pins required.')
 
             self.find_clk_edge(miso, mosi, clk, cs)
-