Method of arbitrating access to a data bus and apparatus therefor

• US 5,303,348 A
• Filed: 03/23/1992
• Issued: 04/12/1994
• Est. Priority Date: 02/22/1985
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Dais, Siegfried, Botzenhardt, Wolfgang, Kiencke, Uwe, Krampe, Wolfgang, Litschel, Martin
• Primary Examiner(s): Trans, Vincent N.
• Application Number:
  US07/856,430
• Time in Patent Office: 750 Days
• Field of Search: 340/825.5, 340/825.51, 364/514, 364/935.41, 364/937.01, 364/242.7, 364/242.8, 364/242.9, 364/242.6, 364/431.04, 370/85.6, 370/85.1, 370/85.2, 395/275, 395/200, 395/325, 395/725
• US Class Current: 710/114
• CPC Class Codes: B60R 16/0315 using multiplexing techniques multiplexing for transmission of signals G08C15/00; multiplexing for electrical communication in general H04J
• CPC Class Codes: F02D 41/266 the computer being backed-up or assisted by another circuit, e.g. analogue
• CPC Class Codes: F02P 5/1502 using one central computing unit
• CPC Class Codes: G06F 11/0736 in functional embedded systems, i.e. in a data processing system designed as a combination of hardware and software dedicated to performing a certain function testing or monitoring of automated control systems G05B23/02
• CPC Class Codes: G06F 11/0739 in a data processing system embedded in automotive or aircraft systems
• CPC Class Codes: G06F 11/0745 in an input/output transactions management context input/output processing in general G06F13/00
• CPC Class Codes: G06F 11/0763 by bit configuration check, e.g. of formats or tags
• CPC Class Codes: G06F 11/0772 Means for error signaling, e.g. using interrupts, exception flags, dedicated error registers
• CPC Class Codes: G06F 11/10 Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
• CPC Class Codes: G06F 13/374 using a self-select method with individual priority code comparator
• CPC Class Codes: H04L 1/0082 fields explicitly indicating existence of error in data being transmitted, e.g. so that downstream stations can avoid decoding erroneous packet; relays
• CPC Class Codes: H04L 12/40163 by assigning priority to messages according to a message field
• CPC Class Codes: H04L 12/4135 using bit-wise arbitration
• CPC Class Codes: H04L 2001/0094 Bus
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle
• CPC Class Codes: H04L 25/026 Arrangements for coupling transmitters, receivers or transceivers to transmission lines; Line drivers duplexing arrangements H04L5/14
• CPC Class Codes: H04L 25/0272 Arrangements for coupling to multiple lines, e.g. for differential transmission
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method is disclosed for the operation of a data processing system for motor vehicles including at least two computers and a line connecting the computers for the transmission of messages. This line permits a fast and reliable data transmission between the computers installed in the motor vehicle, taking into account the specific requirements of a controller-coupling in the motor vehicle. An embodiment is provided which describes in detail the interface between the individual computers and the line linking the computers, and with the aid of which a controller-coupling is realized in the vehicle.

Claims

1. A method of setting up messages for operating a data processing apparatus having a plurality of stations interconnected by a serial data bus for transmitting messages, the messages each having a head part and a data part as well as a data name and a priority for transferring messages to a plurality of the stations via the serial data bus, the method comprising the steps of:

generating a plurality of said messages in at least one of said stations;

connecting said plurality of stations to said serial data bus;

configuring the head part as an identifier of each message to define the contents of the data field by holding a name and a priority for determining accessibility to the data bus;

determining admission to the data bus by the priority fixed in the head part of the message by comparing on bit level the bit level each transmitting station transmits to the bus with the bit level it actually senses on the bus; and

,

stopping transmission of the messages without destroying information on the bus if the bit levels are not identical and completing the transmission if the head part has the highest priority.

2. The method of claim 1, wherein said data processing apparatus if for a motor vehicle and said data bus is mounted on the motor vehicle.

3. The method of claim 1, wherein the identifier identifies data contents selected from the group comprising copy addresses, sensor signals, actuating variables, intermediate results, commands for synchronization and commands for triggering actions.

4. The method of claim 1, wherein the identifier identifies data contents selected from the group comprising engine speed, engine speed gradient, engine temperature and engine load.

5. The method of claim 1, wherein the higher priority of the message is determined by making the first different bit dominant with respect to the head part of other messages.

6. An apparatus for processing data for a control system, the apparatus comprising:

a plurality of stations and at least one of said stations including means for generating a plurality of messages;

a serial data bus interconnecting said stations for transferring messages between said stations;

said messages each having a head part and a data part as well as a data name and a priority for transferring messages to a plurality of the stations via the serial data bus;

the head part being configured as an identifier of each message to define the contents of the data part by holding a name and a priority for determining accessibility to the data bus;

means for determining admission to the data bus by the priority fixed in the head part of the message by comparing on bit level the bit level each transmitting station transmits to the bus with the bit level it actually senses on the bus; and

,

means for stopping transmission of the messages without destroying information on the bus if the bit levels are not identical and completing the transmission if the head part has the highest priority.

7. The method of claim 6, wherein said data processing apparatus is for a motor vehicle and said data bus is mounted on the motor vehicle.