Handling of Wake-Up Messages in Controller Area Networks

• US 20130318380A1
• Filed: 05/28/2012
• Published: 11/28/2013
• Est. Priority Date: 05/28/2012
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Behrens, Frank Herman, Domingues, Patricia Elaine, Marnho, Marcelo, de Holanda, Jos Arnaldo Mascagni
• Granted Patent: US 9,112,721 B2
• Time in Patent Office: Days
• US Class Current: 713/323
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 12/40039 Details regarding the setting of the power status of a node according to activity on the bus
• CPC Class Codes: H04L 2012/40215 Controller Area Network CAN
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Systems and methods for handling wake-up messages in a Controller Area Network (CAN) are described. In some embodiments, a method may include operating a CAN controller in a selected one of a plurality of operating modes in response to the detection of an event or activity on a CAN bus. The method may also include handling, by the CAN controller, a CAN message using a message handling protocol associated with the selected one of the plurality of operating modes, for example, while a host processor operates in a low power mode. In various implementations, each of the plurality of operating modes may correspond to a different amount of power consumption by the CAN controller. The method may further include transmitting a selected one of a plurality of response messages by the CAN controller over the CAN bus, in some cases, without waking up the processor from the low power mode.

Claims

1. A method, comprising:

in response to activity detected on a Controller Area Network (CAN) bus, operating a CAN controller of a host processor in a selected one of a plurality of operating modes; and

handling, by the CAN controller, a CAN message received over the CAN bus using a message handling protocol associated with the selected one of the plurality of operating modes, at least in part, while at least one processor core of the host processor operates in a low power mode.

2. The method of claim 1, wherein each of the plurality of operating modes corresponds to a different amount of power consumption by the CAN controller.

3. The method of claim 2, wherein handling the CAN message includes comparing, according to the message handling protocol, at least one portion of the CAN message to stored information.

4. The method of claim 3, wherein the at least one portion of the CAN message includes a message identification, and wherein the stored information includes stored message identification information.

5. The method of claim 4, wherein the message handling protocol includes a sequence of one or more logical operations to be performed in the comparison between the message identification and the stored message identification information.

6. The method of claim 3, further comprising:

in response to the at least one portion of the CAN message not matching the stored information, operating the CAN controller in another operating mode, the other operating mode corresponding to a lesser amount of power consumption than the selected operating mode;

or

in response to the at least one portion of the CAN message matching the stored information, operating the CAN controller in yet another operating mode, the yet another operating mode corresponding to a higher amount of power consumption than the selected operating mode.

7. The method of claim 3, further comprising:

waking up the at least one processor core from the low power mode, at least in part, in response to the at least one portion of the CAN message matching the stored information.

8. The method of claim 1, wherein handling the CAN message includes transmitting a selected one of a plurality of response messages by the CAN controller over the CAN bus without waking up the at least one processor core from the low power mode.

9. The method of claim 1, further comprising:

receiving, at the CAN controller, an identification of the selected one of the plurality of operating modes, the identification having been configured by the at least one processor core prior to the at least one processor core having entered the low power mode.

10. The method of claim 1, further comprising:

receiving, at the CAN controller, an identification of allowed ones of the plurality of operating modes, the identification having been configured by the at least one processor core prior to the at least one processor core having entered the low power mode; and

identifying, by the CAN controller, the selected one of the plurality of operating modes among the allowed ones of the plurality of operating modes, at least in part, in response to contents of the CAN message.

11. A Controller Area Network (CAN) controller, comprising:

message processing circuitry configured to receive an indication of a selected one of a plurality of operating modes, each of the plurality of operating modes corresponding to a different level of power consumption and to a different CAN message handling protocol, the message processing circuitry further configured to handle a received CAN message using a CAN message handling protocol associated with the selected operating mode; and

power control circuitry operably coupled to the message processing circuitry, the power control circuitry configured to implement the selected operating mode within the CAN controller.

12. The CAN controller of claim 11, wherein the power control circuitry is further configured to switch operation from a low power mode to the selected operating mode, the selected operating mode corresponding to a higher level of power consumption by the CAN controller than the low power mode, and wherein the message processing circuitry is further configured to attempt to match at least one portion of the received CAN message to stored information according to the CAN message handling protocol associated with the selected operating mode.

13. The CAN controller of claim 12, wherein the power control circuitry is further configured to switch operation from the selected operating mode to the low power mode in response to a failed match between the at least one portion of the received CAN message and the stored information by the message processing circuitry, and wherein the message processing circuitry is further configured to wake up a host processor from a sleep mode in response to a successful match between the at least one portion of the received CAN message and the stored information.

14. The CAN controller of claim 12, wherein the message processing circuitry is further configured to transmit a selected one of a plurality of CAN messages in response to the received CAN message and without waking up a host processor from a sleep mode.

15. The CAN controller of claim 11, wherein the indication of the selected one of the plurality of operating modes includes a selected one of the different levels of power consumption by the CAN controller, and wherein the message processing circuitry is further configured to identify the selected one of the plurality of operating modes based, at least in part, upon the selected one of the different levels of power consumption.

16. A Controller Area Network (CAN) node, comprising:

a host processor including a core and a CAN controller operably coupled to the core, the CAN controller configured to receive an indication of at least one of a plurality of operating modes and to handle a received CAN message using a message handling protocol associated with the at least one of the plurality of operating modes while the core operates in a low power mode, each of the plurality of operating modes corresponding to a different amount of power consumption by the CAN controller.

17. The CAN node of claim 16, wherein the indication identifies a single one of the plurality of operating modes of the CAN controller, and wherein the indication is configured to cause the CAN controller to switch its operation from a low power mode to the single one of the plurality of operating modes to handle the CAN message.

18. The CAN node of claim 16, wherein the indication identifies two or more of the plurality of operating modes, and wherein the indication is configured to allow the CAN controller to select one of the identified operating modes, at least in part, in response to information within the received CAN message.

19. The CAN node of claim 16, wherein the core is configured to continue operating in the low power mode during handling of the received CAN message by the CAN controller and during transmission of a response message by the CAN controller.

20. The CAN node of claim 16, wherein the core is configured to wake up from the low power mode in response to a command or interrupt set by the CAN controller.