D2B divice address initialization by use of default address

• US 5,675,571 A
• Filed: 03/13/1995
• Issued: 10/07/1997
• Est. Priority Date: 06/25/1993
• Status: Expired due to Fees

• Current Assignee: D2B Systems Co. Ltd. (Koninklijke Philips N.V.)
• Original Assignee: D2B Systems Co. Ltd. (Koninklijke Philips N.V.)
• Inventors: Wilson, Neil A.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Nguyen, Chau T.
• Application Number:
  US08/382,058
• Time in Patent Office: 939 Days
• Field of Search: 370/60, 370/85.1, 370/85.11, 370/85.3, 370/85.2, 370/92, 370/94.1, 340/825.07, 340/825.52, 340/825.54, 395/824, 395/829, 348/721
• US Class Current: 370/475
• CPC Class Codes: G06F 12/0669 with decentralised address assignment
• CPC Class Codes: H04L 12/4135 using bit-wise arbitration
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
• CPC Class Codes: H04L 61/5046 Resolving address allocation conflicts; Testing of addresses testing when self-assigning an address H04L61/5092

Abstract

In a single channel communication bus system, e.g. D₂ B, sometimes two devices of the same type must be initialized at the same time. These devices start out with the same address installed by the manufacturer. The installed address includes follower bits which can be changed to account for the presence of other devices. During initialization, all devices are set to a dummy address and the installed address is stored. Each station then looks for devices having its own installed address. If, after 3 tries, none is found then the stored address is used. If other devices having the installed address are found, the follower bits can be changed. The station iterates until all possible follower bits are exhausted. In this way the stations of the same type have an improved likelihood of being initialized with distinct addresses.

Claims

1. A single channel communication bus system comprising a communication bus having a plurality of stations connected thereto, which stations can communicate with one another via the communication bus, to each of which stations a unique station address is to be assigned, each of said respective stations comprising a respective interface circuit for

calling any destination station by generating a destination station address for that destination stations,

receiving an acknowledge signal that is transmitted by that destination station, if the station address of that destination station corresponds to the transmitted destination station address, interface circuit of a station is further adapted to

performing an initialization program under the control of which the interface circuit generates and transmits the destination station address more than one time,

discontinuing generating and transmitting upon absence of the acknowledge signal, and the destination station address which has been generated and transmitted being assigned as a master station address for the respective station,

characterized in that each station, before sending a destination station address during the initialization program, adopts a default address.

2. A single channel communication bus as claimed in claim 1, characterized that each station, upon receipt of acknowledgement upon transmission of the destination station address during initialization, aborts the initialization program and adopts the default address as its own unique address.

3. A single channel communication bus as claimed in claim 1, characterized in that

upon start of the initialization program with a first address, which is acknowledged, the interface under control of the initialization program transmits and generates a plurality of different destination station addresses in a predetermined sequence, said generation and transmission being discontinued upon absence of the acknowledge signal and the destination station address, which is the last that has been transmitted being assigned as the master station address to said station upon absence of the acknowledge signal.

4. A single channel communication bus system as claimed in claim 1, characterized in that each station has a non volatile memory for storing the address assigned to said station, whereby upon start of the initialisation program the generation and transmission of the different destination station addresses is starting by the address stored previously in said non volatile memory.

5. A single channel communication bus system as claimed in claim 1, characterized in that the address generated and transmitted in the initialisation program comprises a fixed part which depends on the type of station, and a variable part which comprises a fixed number of bits.

6. A single channel communication bus system as claimed in claim 5, characterized in that after each generation and transmission of destination station address which is acknowledge by another station on the bus system is incremented by one for some subsequently being transmitted on the communication bus and that initialisation is aborted upon generation and transmission and acknowledgment of all possible addresses available under the fixed number of bits in the variable part of the potential station address.

7. A single channel communication bus as claimed in claim 1, characterized in that the default address is is not normally expected to be used by any station operating after initialization in the bus system.

8. A single channel communication bus as claimed in claim 2, characterized in that upon start of the initialization program with a first address, which is acknowledged, the interface under control of the initialization program transmits and generates a plurality of different destination station addresses in a predetermined sequence, said generation and transmission being discontinued upon absence of the acknowledge signal and the destination station address, which is the last that has been transmitted being assigned as the master station address to said station upon absence of the acknowledge signal.

9. A single channel communication bus system as claimed in claim 2, characterized in that each station has a non volatile memory for storing the address assigned to said station, whereby upon start of the initialization program the generation and transmission of the different destination station addresses is starting by the address stored previously in said non volatile memory.

10. A single channel communication bus system as claimed in claim 3, characterized in that each station has a non volatile memory for storing the address assigned to said station, whereby upon start of the initialization program the generation and transmission of the different destination station addresses is starting by the address stored previously in said non volatile memory.

11. A single channel communication bus system as claimed in claim 8, characterized in that each station has a non volatile memory for storing the address assigned to said station, whereby upon start of the initialization program the generation and transmission of the different destination station addresses is starting by the address stored previously in said non volatile memory.

12. A single channel communication bus system as claimed in claim 2, characterized in that the address generated and transmitted in the initialization program comprises a fixed part which depends on the type of station, and a variable part which comprises a fixed number of bits.

13. A single channel communication bus system as claimed in claim 3, characterized in that the address generated and transmitted in the initialization program comprises a fixed part which depends on the type of station, and a variable part which comprises a fixed number of bits.

14. A single channel communication bus system as claimed in claim 8, characterized in that the address generated and transmitted in the initialization program comprises a fixed part which depends on the type of station, and a variable part which comprises a fixed number of bits.

15. A single channel communication bus system as claimed in claim 12, characterized in that after each generation and transmission of destination station address which is acknowledge by another station on the bus system is incremented by one for some subsequently being transmitted on the communication bus and that initialization is aborted upon generation and transmission and acknowledgment of all possible addresses available under the fixed number of bits in the variable part of the potential station address.

16. A single channel communication bus system as claimed in claim 13, characterized in that after each generation and transmission of destination station address which is acknowledge by another station on the bus system is incremented by one for some subsequently being transmitted on the communication bus and that initialization is aborted upon generation and transmission and acknowledgment of all possible addresses available under the fixed number of bits in the variable part of the potential station address.

17. A single channel communication bus system as claimed in claim 14, characterized in that after each generation and transmission of destination station address which is acknowledge by another station on the bus system is incremented by one for some subsequently being transmitted on the communication bus and that initialization is aborted upon generation and transmission and acknowledgment of all possible addresses available under the fixed number of bits in the variable part of the potential station address.

18. A single channel communication bus as claimed in claim 2, characterized in that the default address is not normally expected to be used by any station operating after initialization in the bus system.

19. A single channel communication bus as claimed in claim 3, characterized in that the default address is not normally expected to be used by any station operating after initialization in the bus system.

20. A single channel communication bus as claimed in claim 8, characterized in that the default address is not normally expected to be used by any station operating after initialization in the bus system.

21. A station for use with a single channel communication bus, the station comprising an installed master address and an interface circuit for interfacing with said bus, which interface circuit stores an initialization program which includes

code for using the installed master address as a temporary destination address and using a dummy address as a temporary master address;

code for repeatedly sending out a message checking whether other stations connected to the bus are using the temporary destination address;

code for seeking an acknowledgement of the message;

code for, upon no receipt of an acknowledgement, installing the temporary destination address as a master address.

22. The station of claim 21 wherein the code for seeking an acknowledgement sends the message three times and only concludes that there is no acknowledgement after those three times are over.

23. The station of claim 21 wherein the temporary destination address comprises disambiguation bits;

and

the interface circuit further comprises

code for, upon receipt of the acknowledgement, altering the disambiguation bits of the temporary destination address; and

code for iteratively seeking the acknowledgement and altering disambiguation bits until no acknowledgement is received; and

when the temporary destination address is reinstalled as the master address, any altered disambiguation bits are included in the master address.

24. The station of claim 22 wherein the temporary destination address comprises disambiguation bits;

and

the interface circuit further comprises

code for, upon receipt of the acknowledgement, altering disambiguation bits of the temporary destination address; and

code for iteratively seeking of the acknowledgement and altering disambiguation bits until no acknowledgement is received; and

when the temporary destination address is reinstalled as the master address, any altered disambiguation bits are included in the master address.

25. A bus system comprising

a plurality of stations as claimed in claim 21;

and

a single channel communication bus for allowing the stations to communicate with each other and themselves.