US 9,294,412 B2 · Controller area network (CAN) worst-case message latency with priority inversion

Abstract

This application discloses determining a worst-case latency in a controller area network (CAN) for messages experiencing priority inversion within individual controllers. A system to determine the worst-case latency can include a memory system to store computer-executable instructions and a computing system, in response to execution of the computer-executable instructions, can identify that a controller area network (CAN) design includes a controller configured to sequence messages for transmission over a shared bus with at least one of the messages experiencing priority inversion. The computing system also can determine a delay for the controller to present a first message to the shared bus for transmission when the first message is ordered behind a second message having a lower priority than the first message. The delay may be a portion of the worst-case latency corresponding to the priority inversion.

Claims15

Dependent claims

A method comprising:

receiving, by a computing device, parameters associated with a controller area network (CAN) having multiple controllers configured to transmit messages over a shared bus based, at least in part, on priorities associated with the messages, wherein the parameters are configured to identify that at least one of the controllers is configured to internally order a subset of the messages for presentation to the shared bus with priority inversion, and wherein the parameters identify each message available to be delivered over the shared bus, a frame period on the shared bus, a transmission time of a frame on the shared bus, and an offset between an initiation of message delivery and a start of the frame period;
and
determining, by the computing device, a delay in delivery of a target message through the controller area network caused by the priority inversion based, at least in part, on the parameters.

A system comprising:

a memory system configured to store computer-executable instructions;
and
a computing system, in response to execution of the computer-executable instructions, is configured to identify that a controller area network (CAN) design includes a controller configured to sequence messages for transmission over a shared bus, and to determine a worst-case latency associated with a delivery of a first message over the shared bus in the controller area network design, wherein the worst-case latency includes a first time to generate of the first message, a second time for the first message to gain access to the shared bus, which includes a delay for the controller to present the first message to the shared bus for transmission when the first message is ordered behind a second message having a lower priority than the first message, a third time for the first message to transmit over the shared bus, and a fourth time to deliver the first message from the shared bus to a destination endpoint device.

An apparatus comprising at least one computer-readable memory device storing instructions configured to cause one or more processing devices to perform operations comprising:

identifying a controller area network (CAN) design includes a controller configured to sequence messages for transmission over a shared bus;
and
determining a worst-case latency associated with a delivery of the first message over the shared bus in the controller area network design, wherein the worst-case latency includes a first time to generate of the first message, a second time for the first message to gain access to the shared bus, which includes a delay for the controller to present the first message to the shared bus for transmission when the first message is ordered behind a second message having a lower priority than the first message, a third time for the first message to transmit over the shared bus, and a fourth time to deliver the first message from the shared bus to a destination endpoint device.

Dependencies are inferred from the claim text.

Controller area network (CAN) worst-case message latency with priority inversion

Life of this patent

Controller area network (CAN) worst-case message latency with priority inversion

Life of this patent

Abstract

Claims15