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Automotive Buses and Vehicle Bus Description

Automotive Buses and Vehicle Bus Description

Automotive Buses

[BST bus]
[CAN bus]
[DSI bus]
[J1708 bus]
[J185 bus]
[LIN bus] [MEC bus]
[MI bus]
[MML bus]

[Amazon Engine Diagnostic Products]
[Bus Info Page]

Note: There are six classifications of vehicle Buses:
Class A, Class B, Class C, Emissions/Diagnostics, Mobile Media, and
Many of the buses listed below have a notation defining what
class they reside in.
Class A: A multiplex wiring system which reduces wiring by
transmitting and receiving multiple signals over the same signal bus.
The multi-purpose bus replaces individual wires performing the same function.
Normally Class A defines general purpose UART communication with bit
rates below 10kbps
Class B: A multiplex wiring system which transmits data between
nodes. The nodes replace existing stand-alone modules.
Class B is used as a non-critical 10kbps to 125kbps bus
Class C: A multiplex wiring system which reduces wiring by using
real-time high-data signals. Operating between 125kbps and 1Mbps
Emissions/Diagnostics: handle either Emissions or Diagnostics
Mobile Media: buses handle Mobile Media equipment.
X-by-Wire: is the collective term for the addition of electronic systems into the vehicle to enhance and replace tasks that were
previously accomplished via mechanical and hydraulic systems.
Automotive temperature requirements are -40C to +125C.

In addition, a number of the listed buses define the Electrical Physical
layer and the Optical Physical layer, which is normal for a bus which
defines both interface types.
The Physical interface bus being either
fiber [Optical] or wire [electrical]. The difference here, in some cases,
is that the electrical interface being defined resides just prior to the
optical encoder. So the Physical interface bus from device to device is
optical [fiber], but the specification also defines the Physical
[electrical] interface into the optical transmitter/receiver [which is
not normally done outside of Automotive buses].
Also: … “It is becoming clear that regardless of carmaker, new vehicles
will be made using LIN for the lowest data-rate functions, CAN for medium
speed, MOST for the high-speed data rates and FlexRay, for
safety-critical applications such as steer- and brake-by-wire.” from
Automotive Industries.

MOST bus Description

MOST bus: [Media Oriented Systems Transport],defines a multimedia
fiber-optic (low overhead, low cost) point-to-point network implemented
in a ring, star or daisy-chain topology over Plastic optical fibers
The MOST bus specifications define the Physical [Electrical and Optical parameters] Layer as well as the Application Layer, Network Layer, and Medium Access Control.
The MOST bus provides an optical solution for automotive media [entertainment] networks [Video, CD..].

J1850 bus Description

The SAE J1850 bus is used for
diagnostics and data sharing applications in On and Off road vehicles.