An improved serial data protocol/format is provided in a serial multiplex system for use in an automotive vehicle electrical system which is subject to electrical noise The protocol/format includes successive transactions between a master controller and respective remote controllers each connected to a serial multiplex bus Each transaction is bidirectional and includes a command message transmitted by the master controller and a reply message normally transmitted by an answering remote controller Each command message is preceded by a multibit SYNC byte The command message includes an address byte (for a particular remote controller), a command byte, and an error check such as a cyclic redundance check byte passed on the address and command bytes The reply message includes the address byte of the replying remote controller, a response byte indicative of its response to the command byte, and an error check such as a cyclic redundancy check byte based on the reply address and response bytes The master controller may be caused to repeat the transmission of a command message if the address bytes, the command/response correlations or error check bytes are not verifiable, thereby enhancing the system's ability to detect and/or reject errors as might be occasioned by noise

Vehicle multiplex system having protocol/format for secure communication transactions

of EP0221859An improved electrical system for motor vehicles, enabling the distribution of electrical energy to the various utilisers of the motor vehicle to be optimised in the case of the supply being effected by means of a single cable. This electrical system, in practice, includes the said supply cable, apparatus operable substantially to modulate the supply as a function of times and/or loads and/or the required priority of the aforesaid services. The control of the individual services, in particular, can be effected both with a single wire system and with any other system which involves the separation of the supply energy from the control energy.

Electrical power distribution system for a motor vehicle.

A number of connecting units are combined in parallel onto a single control line connected to a central unit whose input circuits are connected to switches on the vehicle dashboard. When a switch is operated, the central unit issues a binary coded signal to address the unit to be controlled. The address signal also contains data bits which signal adjustment of the supply voltage for the controlled unit. Two other data bits in the address signal are placed on the control line, after the addressing process, to verify and signal the operating state for an indicator on the dashboard. Each control command is preceded by three logic zero pulses.

Boucheron Jean-Louis

Papers

Control unit for motor vehicle electrical equipment - issues binary coded signals for control and test of equipment