Network device interface for digitally interfacing data channels to a controller via a network

• US 6,708,239 B1
• Filed: 12/12/2000
• Issued: 03/16/2004
• Est. Priority Date: 12/08/2000
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Konz, Daniel W., Ellerbrock, Philip J., Grant, Robert L., Winkelmann, Joseph P.
• Primary Examiner(s): Dang, Khanh
• Application Number:
  US09/735,146
• Time in Patent Office: 1,190 Days
• Field of Search: 710/21, 710/25, 710/53, 710/62, 710/72, 710/69, 700/286, 700/292, 700/22, 709/201, 709/238
• US Class Current: 710/62
• CPC Class Codes: H04L 12/40032 Details regarding a bus interface enhancer
• CPC Class Codes: H04L 12/4135 using bit-wise arbitration
• CPC Class Codes: H04L 2012/40215 Controller Area Network CAN
• CPC Class Codes: H04L 2012/4028 the transportation system being an aircraft
• CPC Class Codes: H04L 25/4904 using self-synchronising codes, e.g. split-phase codes

Abstract

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface uses a specialized protocol for communicating across the network bus that uses a low-level instruction set and has low overhead for data communication.

Claims

1. A method of addressing groups of data channels that are each adapted to communicate with a bus controller via a common digital bus, the method comprising:

constructing an individual mask for each data channel, wherein the mask comprises a plurality of bits, wherein each bit of the mask represents a respective group to which the data channel may belong and has a first state indicating that the respective data channel is a member of the group and a second state indicating that the respective data channel is a nonmember of the group;

transferring each mask to its respective data channel; and

thereafter transmitting a first message from the bus controller to the data channels, wherein the first message identifies group of data channels that are designated to process the first message;

determining, at each data channel, if the respective data channel is a member of the group identified in the first message by analyzing the mask associated with the respective data channel; and

processing the first message only if the respective data channel is a member of the group identified in the first message.

2. A method according to claim 1 further comprising storing the mask at its respective data channel.

3. A method according to claim 1 wherein one of the data channels is a member of more than one group and wherein said constructing step constructs the mask associated with the data channel such that the bits of the mask associated with the groups which the data channel is a member of are set to a first state and all bits of the mask associated with groups that the data channel is not a member of are set to the second state.

4. A method according to claim 1 further comprising establishing a different logical address for each data channel such that each data channel is also individually addressable.

5. A method according to claim 1 further comprising establishing a global address for all data channels such that all data channels are addressable by using the global address.

6. A method according to claim 1, wherein if a data channel belongs to more than one group, said constructing step constructs the mask associated with the data channel such that the bits of the mask associated with the groups which the data channel is a member of are set to a first state.

7. A method according to claim 1, wherein the bus controller sends a first message to a first data channel twice as often as the bus controller sends the first message to a second data channel,

wherein the first data channel is a member of both a first and a second group of data channels and the second data channel is a member of only the second group of data channels,

wherein said constructing a mask step constructs an individual mask for both the first data channel and the second data channel,

wherein for the first data channel said processing element sets the bits of the mask associated with the first and second group to a first state indicating in the mask that the first data channel is a member of both the first and second groups,

wherein for the second data channel said processing element sets the bit of the mask associated with the second group to a first state indicating in the mask that the second data channel is a member of the second group and sets the bit of the mask associated with the first group to a second state indicating in the mask that the second data channel is not a member of the first group,

wherein the first message includes a command and a group address designating the group of data channels designated to process the command,

wherein said transmitting step transmits the first address to the data channels to command the data channels,

wherein at a first time, said transmitting step transmits a first message having a command and a group address, where the group address designates the first group of data channels to process the command, and

wherein at a second time, said transmitting step transmits a first message having a command and a group address, where the group address designates that both the first and second group of data channels to process the command.

8. A system for addressing groups of data channels adapted to communicate with a bus controller via a common digital bus, the system comprising:

a processing element for constructing an individual mask for each data channel, wherein the mask comprises a plurality of bits, wherein each bit of the mask represents a respective group to which the data channel may belong and has a first state indicating that the respective data channel is a member of the group and a second state indicating that the respective data channel is a nonmember of the group;

a transmitter connected to said processing element for transferring each mask to its respective data channel; and

a network device interface adapted to interconnect the bus controller with an associated data channel,

wherein said bus controller transmits a first message to the data channels, wherein the first message identifies a group of data channels that are designated to process the first message,

wherein a network device at each data channel determines if the respective data channel is a member of the group identified in the first message by analyzing the mask associated with the respective data channel with the group identified in the first message and processes the first message only if the respective data channel is a member of the group identified in the first message.

9. A system according to claim 8, wherein one of the data channels is a member of more than one group and, wherein said processing element constructs the mask associated with the data channel such that the bits of the mask associated with the groups which the data channel is a member of are set to a first state and all bits of the mask associated with groups that the data channel is not a member of are set to the second state.

10. A system according to claim 8, wherein said processing element establishes a different logical address for each data channel such that each data channel is also individually addressable.

11. A system according to claim 8, wherein said processing element establishes a global address for all data channels such that all channels are addressable by using the global address.

12. A system according to claim 8, wherein if a data channel belongs to more than one group, said processing element constructs the mask associated with the data channel such that the bits of the mask associated with the groups which the data channel is a member of are set to a first state.

13. A system according to claim 8, wherein the bus controller sends a first message to a first data channel in the group of data channels twice as often as the bus controller sends the first message to a second data channel,

wherein the first data channel is a member of both a first and a second group of data channels and the second data channel is a member of only the second group of data channels,

wherein said processing element constructs an individual mask for both the first data channel and the second data channel,

wherein for the first data channel said processing element sets the bits of the mask associated with the first and second groups to a first state indicating in the mask that the first data channel is a member of both the first and second groups,

wherein for the second data channel said processing element sets the bit of the mask associated with the second group to a first state indicating in the mask that the second data channel is a member of the second group and sets the bit of the mask associated with the first group to a second state indicating in the mask that the second data channel is not a member of the first group,

wherein the first message includes a command and a group address designating the group of data channels designated to process the command,

wherein said bus controller transmits the first address to the data channels to command the data channels,

wherein at a first time, said bus controller transmits a first message having a command and a group address, where the group address designates the first group of data channels to process the command, and

wherein at a second time, said bus controller transmits a first message having a command and a group address, where the group address designates that both the first and second group of data channels to process the command.

14. A system according to claim 8, wherein said processing element and transmitter are located in said bus controller.

15. A system according to claim 8, wherein the first message comprises a command and a group address and said network device interface comprises:

a receiver for receiving the first from said bus controller

an address decoder for analyzing the group address located in the first message to determine if the first message is addressed to the data channel associated with the network device interface, said address decoder including a the mask constructed by the processing element for the data channel where each bit of the mask represents a respective group to which the data channel may belong and has a first state indicating that the respective data channel is a member of the group and a second state indicating that the respective data channel is a nonmember of the group, wherein in response to the receipt of the first message, said address decoder compares the group address located in the first message with the mask associated with the data channel to determine whether the data channel is a member of the group designated by the group address located in the first message; and

a device interface for providing the command located in the first message to the data channel associated with the network device if the address decoder determines that the data channel is a member of the group defined by the group address located in the first message.

16. A system according to claim 15 wherein said address decoder comprises a memory element for storing the mask.

17. A system according to claim 15 wherein the address decoder further includes a unique logical address for the associated data channel such that the associated data channel is also individually addressable.