can: implement bit rate switch support for CAN-FD frames
authorStephan Thiele <stephan.thiele@mailbox.org>
Wed, 13 Nov 2019 22:24:31 +0000 (23:24 +0100)
committerUwe Hermann <uwe@hermann-uwe.de>
Fri, 29 Nov 2019 19:33:48 +0000 (20:33 +0100)
decoders/can/pd.py

index faed45e0cc6057730ca7d1889a047df60751ef7d..3ab82b02c054dea02f0c5b4b7c0fbac0564f2917 100644 (file)
@@ -80,6 +80,16 @@ class Decoder(srd.Decoder):
     def start(self):
         self.out_ann = self.register(srd.OUTPUT_ANN)
 
+    def set_bit_rate(self, bitrate):
+        self.bit_width = float(self.samplerate) / float(bitrate)
+        self.sample_point = (self.bit_width / 100.0) * self.options['sample_point']
+
+    def set_nominal_bitrate(self):
+        self.set_bit_rate(self.options['nominal_bitrate'])
+
+    def set_fast_bitrate(self):
+        self.set_bit_rate(self.options['fast_bitrate'])
+
     def metadata(self, key, value):
         if key == srd.SRD_CONF_SAMPLERATE:
             self.samplerate = value
@@ -205,6 +215,9 @@ class Decoder(srd.Decoder):
             if can_rx != 1:
                 self.putx([16, ['CRC delimiter must be a recessive bit']])
 
+            if self.fd:
+                self.set_nominal_bitrate()
+
         # ACK slot bit (dominant: ACK, recessive: NACK)
         elif bitnum == (self.last_databit + self.crc_len + 2):
             ack = 'ACK' if can_rx == 0 else 'NACK'
@@ -408,6 +421,12 @@ class Decoder(srd.Decoder):
         # Get the index of the current CAN frame bit (without stuff bits).
         bitnum = len(self.bits) - 1
 
+        if self.fd and can_rx:
+            if bitnum == 16 and self.frame_type == 'standard' \
+                    or bitnum == 35 and self.frame_type == 'extended':
+                self.dom_edge_seen(force=True)
+                self.set_fast_bitrate()
+
         # If this is a stuff bit, remove it from self.bits and ignore it.
         if self.is_stuff_bit():
             self.putx([15, [str(can_rx)]])