The encyclopedia · Engineering & Operations · Technical decision · 1983-1993
Bosch's CAN bus won cars by letting the wire itself settle priority.
In 1986 Bosch's CAN gave a car a bus with no central master: a frame's identifier set its priority, and ISO 11898 made it the automotive staple.
Robert Bosch GmbH · Mercedes-Benz
the move
By the early 1980s cars were gaining electronics, but the serial buses available could not meet automotive needs, so in 1983 Bosch engineer Uwe Kiencke began a new bus.
Introduced at the SAE congress in February 1986 as the Automotive Serial Controller Area Network, CAN used non-destructive arbitration: no central instance, frames identified by content, the identifier doubling as priority, and faulty nodes auto-disconnected to keep the rest talking.
Intel delivered the first CAN controller (the 82526) in 1987, and ISO 11898 was published in November 1993. Mercedes-Benz ran engine control units on CAN from 1991, and nearly every new European passenger car now has at least one CAN network.
why it works
- Arbitration lives in the bus, so there is no central scheduler to fail
- Frames are addressed by content, not node, so new sensors need no rewiring
- One twisted pair replaced a growing, expensive bundle of wires
- Bosch published the spec and cheap controller chips soon appeared
what transfers
Sometimes the winning move is a lower-level rule that lets a system govern itself: make priority a property of the message, not of a central scheduler.
what came after
CAN spread from cars to trains, ships, industrial controls and machine tools (via CANopen and DeviceNet), and became one of the most widely used serial buses in the world. Later extensions such as CAN FD and FlexRay addressed its limits.
references
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