The experts on this forum say to use IDA Pro, but isn't this like about 1500 GBP? Pretty sure the "free for personal use" version doesn't support the C166.
I have had a quick look at the infineon uVision IDE and Disassembler and free HxD hex editor to process the C166 Bin. Is it possible to use these free tools to have a play and learn about the ECU, or do I really need to get a copy of the IDA Pro full version?
Incidentally, the Infineon documentation covers multiple derivatives of the C166 family. Are there specific versions I should be focusing on, or is just a general knowledge of the family good enough for a starting point?
General knowledge is fine to start - the memory/peripheral map between CPUs is going to be the main thing that will matter in disassembly and you'll probably look that up as reference each time you go to load a new BIN.
Highly recommended you "source" IDA from somewhere - yes, it's expensive, but there's no competition right now. Ghidra has a TriCore module now thanks to a very dedicated user from the community (I wonder if they are on here?), but no C166 yet.
You would have to be very hardcore to get uVision to be useful for you. IDA is really the way to go.