style: improve error messages in the Cocotb MFB monitor considering duplicit SOFs and EOFs

Author: danielkondys

python/cocotbext/cocotbext/ofm/mfb/monitors.py

@@ -102,15 +102,15 @@ async def _monitor_recv(self):
                         # Checking for beginning of a packet.
                         self.log.debug("Frame Start")
                         if in_frame:
-                            raise MFBProtocolError("Duplicate start-of-frame received on MFB bus!")
+                            raise MFBProtocolError("MFB error: a start-of-frame received without an end-of-frame!")
                         in_frame = True
                         frame = b""
 
                         if (self._eof_arr[rr] == 1) and (not eof_done):
                             # Checking if the packet ends in the same regions where it began.
                             self.log.debug("Frame End in single region")
                             if not in_frame:
-                                raise MFBProtocolError("Duplicate end-of-frame received on MFB bus!")
+                                raise MFBProtocolError("MFB error: an end-of-frame received without a start-of-frame!")
                             in_frame = False
                             frame += data_bytes[ss_idx:ee_idx]
                             self.item_cnt += len(data_bytes[ss_idx:ee_idx])*8 // self._item_width