can_rx_statemachine.h File Reference

State machine that decodes and routes incoming CAN frames. More...

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Data Structures
struct	interface_can_rx_statemachine_t
	Dependency-injection interface for the CAN receive state machine. More...

Functions
void	CanRxStatemachine_initialize (const interface_can_rx_statemachine_t *interface_can_rx_statemachine)
	Registers the dependency-injection interface for this module.
void	CanRxStatemachine_incoming_can_driver_callback (can_msg_t *can_msg)
	Primary entry point called by the hardware CAN driver on frame reception.

Detailed Description

State machine that decodes and routes incoming CAN frames.

Copyright

Copyright (c) 2024, Jim Kueneman All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Identifies frame category (OpenLCB message vs CAN control frame), validates destination aliases, extracts framing bits, and dispatches to the appropriate handler in interface_can_rx_statemachine_t.

Author

Jim Kueneman

Date

4 Mar 2026

Function Documentation

CanRxStatemachine_initialize()

void CanRxStatemachine_initialize ( const interface_can_rx_statemachine_t * interface_can_rx_statemachine )

extern

Registers the dependency-injection interface for this module.

Parameters

interface_can_rx_statemachine

Pointer to a populated interface_can_rx_statemachine_t. Must remain valid for the lifetime of the application. All REQUIRED pointers must be non-NULL.

Warning

NOT thread-safe - call during single-threaded initialization only.

Must be called before any CAN frames arrive.

See also

CanRxMessageHandler_initialize - initialize first

CanRxStatemachine_incoming_can_driver_callback

Registers the dependency-injection interface for this module.

CanRxStatemachine_incoming_can_driver_callback()

void CanRxStatemachine_incoming_can_driver_callback ( can_msg_t * can_msg )

extern

Primary entry point called by the hardware CAN driver on frame reception.

Invokes the optional on_receive callback, then classifies the frame as an OpenLCB message or a CAN control frame and dispatches accordingly.

This function is typically called from an interrupt or receive thread and accesses shared resources (FIFOs, buffer lists). It must NOT be called while the main state machine has resources locked. Recommended approaches:

• Interrupt: disable CAN Rx interrupt during lock_shared_resources / unlock_shared_resources.
• Thread: suspend Rx thread or queue frames during the lock window.

Parameters

can_msg

Pointer to the received CAN frame. Must not be NULL. Must remain valid until this function returns.

Warning

NOT thread-safe with the main state machine resource lock.

See also

CanMainStatemachine_run - holds the resource lock briefly

interface_can_rx_statemachine_t::on_receive