Comment by the__alchemist
1 day ago
Don't want or need analog: Just don't enshittify the digital! CAN bus is a great system; don't IoT it or use dark patterns.
1 day ago
Don't want or need analog: Just don't enshittify the digital! CAN bus is a great system; don't IoT it or use dark patterns.
God no, CAN is horrible and the horrors people working around its limitations have brought into the world are even worse.
CAN is really great for what it is. It is one of the simplest ways to get N devices to talk to each other. Really simple and easily debuggable.
Obviously it is too limiting for modern cars so it will get mostly dropped. It clearly is a great protocol though.
What limitations specifically are you referring to?
The packet size is a major one. The lack of larger packets leads to nonsense like the "freshness manager" in things like AUTOSAR's SecOC, or the addressing scheme. Every subsequent CAN extension has tried to rectify both of these in different ways and inevitably failed, which leads to the next layer up the networking stack reinventing the wheel badly. Eventually you end up with UDS.
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I doubt CAN bus will be around that much longer, I know several EV manufacturers are actively phasing it out. Yes, it was revolutionary in it's time but it's a 40 year old standard that doesn't have enough bandwidth for the requirements of modern cars, and it was designed before security was even a thought. It's also unnecessarily complex wiring that adds weight to the car. Even the updated FD standard is only 8 mbps, so it's barely enough for video from a backup camera.
It's a tool that's more than sufficient for most things. Video isn't one of those, and it's a 2-wire bus, so I don't see what the wiring concern is!
As I understand it, newer systems like LVCS and Ethernet use less wire and smaller connectors. Apparently it can save up to 30% of the weight in a wiring harness which would be about 100 lbs. There was a thread on it on HN not long ago.
Video for a backup camera is mandatory on new cars in the US and Europe, so it makes sense to use the same bus.