Can communication controller and method of operating can communication controller
AssigneeRenesas Electronics Corporation
InventorsChristian Mardmöller, Tobias Belitz
Life of this patent
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Abstract
A CAN communication controller and a method of operating a CAN communication controller are disclosed. The CAN communication controller is for transmitting first and second types of frames wherein the first type of frame is used to transmit event-triggered communication data and the second type of frame is used to transmit best effort traffic data, the CAN communication controller configured, in response to transmitting a frame of the second type having a given identifier, to delay arbitration of a following frame of the second type having the given identifier, and not to delay arbitration of a frame of the first type.
Claims12
A controller area network (CAN) communication controller for transmitting first and second types of frames, wherein the first type of frame is used to transmit event-triggered communication data and the second type of frame is used to transmit best effort traffic data, the CAN communication controller configured, in response to transmitting a frame of the second type having a given identifier, to delay arbitration of a following frame of the second type having the given identifier, and not to delay arbitration of a frame of the first type, wherein:
- the CAN communication controller comprises:
- a CAN protocol engine;
- a detector for detecting an end of an enhanced intermission (ITM) that includes ITM and x bits;
- at least one finite state machine including a finite state machine associated with the given identifier which includes at least a first state in which bus arbitration for the second type of frame having the given identifier is allowed and a second state in which bus arbitration for the second type of frame is not allowed;
- and
- a message handler which includes a transmit resource for data best effort traffic data having the given identifier;
- the finite state machine is configured to, in response to the CAN communication controller transmitting the frame of the second type having the given identifier, to transition from the first state to the second state, the detector is configured to, in response to detecting the end of the enhanced ITM, signal the end of the enhanced ITM to the finite state machine, and the finite state machine is configured to, in response the detector signalling the end of the enhanced ITM, transition out of the second state;
- and
- the finite state machine is configured to transition out of the second state into a third state in which bus arbitration for the second type of frame having the given identifier is not allowed, and the finite state machine is configured to, in response to waiting a period of time corresponding to y bits, transition from the third state to the first state.
A method of operating a controller area network (CAN) communication controller for transmitting first and second types of frames, wherein the first type of frame is used to transmit event-triggered communication data and the second type of frame is used to transmit best effort traffic data, the method comprising:
- transmitting a frame of the second type having a given identifier and, in response thereto:
- delaying arbitration of a following frame of the second type having the given identifier;
- not delaying arbitration of a frame of the first type;
- executing a message handler which includes a transmit resource for data best effort traffic data having the given identifier;
- transitioning a finite state machine from a first state to a second state, wherein the finite state machine is associated with the given identifier, the finite state machine includes at least a first state in which bus arbitration for the second type of frame having the given identifier is allowed and a second state in which bus arbitration for the second type of frame is not allowed;
- detecting an end of an enhanced intermission (ITM) that includes ITM and an additional x bits;
- in response to detecting the end of the enhanced ITM, signalling the end of the enhanced ITM to the finite state machine,
- in response signalling the end of the enhanced ITM, transitioning the finite state machine out of the second state;
- transitioning the finite state machine out of the second state into a third state in which bus arbitration for the second type of frame having the given identifier is not allowed;
- and
- in response to waiting a period of time corresponding to y bits, transitioning the finite state machine from the third state to the first state.
Dependencies are inferred from the claim text.