Communication apparatus

• US 20070233919A1
• Filed: 02/08/2007
• Published: 10/04/2007
• Est. Priority Date: 02/13/2006
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Miura, Hisanori
• Granted Patent: US 7,539,804 B2
• Time in Patent Office: Days
• US Class Current: 710/110
• CPC Class Codes: H04L 12/40013 Details regarding a bus controller
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 12/4135 using bit-wise arbitration
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle
• 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 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

An airbag ECU includes a communication bus connection circuit for connecting communication buses to communication circuits. A central control circuit connects some of the communication buses to the communication circuits with the communication bus connection circuit and sets addresses for some of slave sensor devices. When those addresses are set, the other communication buses are connected to the communication circuits by the communication bus connection circuit, and addresses for the other slave sensor devices are set. Thus, a circuit can be made simpler without any influence on address setting, thus reducing cost and size of an airbag apparatus.

Claims

1. A communication apparatus comprising:

a master device having a communication circuit for transmitting and receiving serial data;

a plurality of communication buses over which serial data are transmitted; and

a plurality of slave devices daisy-chain-connected to the communication circuit through respective ones of the communication buses for transmitting and receiving serial data to and from the communication circuit,

wherein the communication circuit sets addresses for the slave devices through the plurality of communication buses at the time of initial setting, and thereafter transmits and receives serial data to and from the plurality of slave devices using the set addresses, and

wherein master device further has a communication bus connecting circuit for sequentially connecting the plurality of communication buses to the communication circuit.

2. The communication apparatus according to claim 1, wherein the master device connects one of the communication buses to the communication circuit by the communication bus connecting circuit to set an address for one of the slave devices daisy-chain-connected to the one of the communication buses, and sequentially connects another of the communication buses to sequentially set addresses for another of the slave devices daisy-chain-connected to the another of the communication buses after the address is set for the one of the slave devices.

3. The communication apparatus according to claim 1, wherein the communication bus connecting circuit includes:

a connection wiring for connecting one of the communication buses to the communication circuit;

a plurality of switches for switchably connecting other of the communication buses to the communication circuit; and

a switch control circuit for controlling switching operations of the switches.

4. The communication apparatus according to claim 1, wherein the communication bus connecting circuit includes:

a plurality of switches for switchably connecting respective ones of the plurality of communication buses to the communication circuit; and

a switch control circuit for controlling switching operations of the plurality of switches.

5. The communication apparatus according to claim 4, wherein the switch control circuit turns off, when any of the slave devices fails, the switch connecting the communication bus connected to the slave device having a failure to the communication circuit.

6. The communication apparatus according to claim 3, wherein the communication circuit, the plurality of switches and the switch control circuit are provided in an integrated circuit.

7. The communication apparatus according to claim 4, wherein the communication circuit, the plurality of switches and the switch control circuit are provided in an integrated circuit.

8. The communication apparatus according to claim 1, wherein:

the plurality of slave devices are sensors for detecting information on a collision of a vehicle; and

the master device is an electronic controller for controlling passenger protection unit in the vehicle based on the information on the collision of the vehicle detected by the plurality of slave devices.