US 5,448,561 AGranted

Method & apparatus for data exchange in data processing installations

AssigneeRobert Bosch GmbH

InventorsKarl-Heinz Kaiser, Herbert Lohner, Hans-Joerg Mathony, Jan Unruh, Uwe Zurmuehl, Udo Brunke, Juergen Glasser, Olaf Linne

Life of this patent

Estimating the term…

patentgrep

Loading patent…

Abstract

An improved method for exchange of data in data processing installations, especially Controller Areas Networks (CAN), permits acknowledged and segmented transmission of data strings, of arbitrarily long length, between at least two stations in the network or other data processing installation. The method includes the transmission of the messages associated with the data by means of frames; the frames contain a header field and a data field. In the event of contention between multiple stations of the data processing installation for access to the bus connection, which frame has priority is determined by evaluating the respective header fields. In the data field of the frame, there is a control information field (58, 95) containing a message code which serves to identify the message type. The message codes distinguish among activation messages (AR, AC), data messages (DT), and acknowledgement (AK) messages. This permits transmission of data strings, of limited length, with acknowledgement. Further, the control information fields (58, 95) of certain messages contain a sequence number, a receiver status code, a message end code, and a code specifying how many data bytes are being transmitted in the frame. With this additional information, data strings of arbitrarily long length may be transmitted as segments. The receipt of the individual partial messages is confirmed by sending back an acknowledgment in each case.

Claims24

Dependent claims

Method for exchange of data with the help of a message in data processing installations having at least two stations (33, 34) connected to one another via a bus, comprising the steps of:

defining a connection (24) between a pair of stations (33, 34) by a pair of oppositely-directed channels (31, 32), each channel extending from a sending object (37, 36) stored in one of said pair of stations to a receiving object (35, 38) stored in the other of said pair of stations;
defining, for purposes of each channel (31, 32), the station storing the sending object (37, 36) as a sending station, and the station storing the receiving object (35, 38) as a receiving station, said sending and receiving stations together defining the connection (24);
transmitting each message, via said connection, in a frame which contains at least a header field and a data field, with said header field being at a beginning portion of said frame, identifying the frame, and indicating a priority value of the frame for purposes of automatic arbitration of access to said bus;
establishing, activating and deactivating said connections (24), via said bus, between pairs of said stations (33, 34);
exchanging messages using said connections;
and
said step of establishing connections including the steps of:
storing, in each station of one said connection (24), information defining a sending object (36, 37), and
storing, in each station of said connection (24), information defining a receiving object (35, 38);
each of said sending object (36, 37) and said receiving object (35, 38) including a header field (39) and a data field (40);
said header field (39) of said sending object (36, 37) specifying the content of a header field of a frame transmitted from said station (34, 33) in which said sending object (37, 36) is stored to said station (33, 34) in which a corresponding receiving object (35, 38) is stored;
and
said frame contains said header field (39) and a control information field (58, 95), which in turn contains at least one message code characterizing what kind of message said frame is carrying and thereby distinguishing among at least:
a message (AR) requesting activation of a connection,
a message (AC) confirming activation of a connection,
a message (DT) transmitting data via said connection, and
a message (AK) acknowledging receipt of a data message.

14 more elements

A data communications system for transmitting, with acknowledgement, data messages comprising

at least two stations (33,34), each containing a computer;
an interface unit in each station;
a bus interconnecting the interface units of the stations;
means, in each interface unit, for generating and transmitting a frame, for receiving a frame, and for recognizing an error in a received frame;
means, within each station, for transferring data between the interface unit and the computer;
means, in each interface unit, for serial data communication over said bus;
wherein
said stations contain protocol means for establishing, activating, and deactivating connections, including sending objects and receiving objects, (24) among said stations;
for exchange of data, with acknowledgement, among stations, via activated connections, a first one of the stations defining a connection sends a Data Transmission (DT) to at least one other station, the other station sends back an AcKnowledgement (AK), the interface unit of the receiving station informs the computer of the receiving station of receipt of the Data Transmission (DT), and the interface unit of the sending station informs the computer of the sending station of receipt of the AcKnowledgement (AK).

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/947,501Filed 16 Sep 1992
Priority: DE 41 31 133.719 Sep 1991
Granted: 5 Sep 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H04L 41/0806
Configuration setting: for initial configuration or provisioning, e.g. plug-and-play
H04L 9/40
Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols: network security protocols
H04L 12/40176
Flexible bus arrangements: involving redundancy
H04L 67/12
Protocols: specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in…