frame.fbs

//***************************************************************************
// Copyright (c) 2022 for information on the respective copyright owner
// see the NOTICE file and/or the following repository:
//     https://github.com/boschglobal/automotive-bus-schema
//
// SPDX-License-Identifier: Apache-2.0
//***************************************************************************



/**
    IDL for Automotive Bus - Stream Interface - Frames
    ==================================================

    MIME Type : application/x-automotive-bus; interface=stream; type=frame; schema=fbs
    Flatbuffers file identifier : SFRA
*/


namespace AutomotiveBus.Stream.Frame;


table Timing {
    // All values are nanoseconds from simulation start time (i.e. from 0.0).
    send:long;          // Timestamp when a Frame is sent to the a Bus
                        // Interface for (later) transmission.
    arbitration:long;   // Timestamp when a Frame is transmitted over the
                        // Bus medium (i.e. message arbitration).
    recv:long;          // Timestamp when a Frame is received from a
                        // Bus Interface and consumed.
}

enum CanFrameType:byte{
    BaseFrame = 0,      // CAN Base Format (Classical):
                        //      frame_id is 11-bits
    ExtendedFrame = 1,  // CAN Extended Format:
                        //      frame_id is 29-bits
    FdBaseFrame = 2,    // CAN FD Base Format:
                        //      frame_id is 11-bits
    FdExtendedFrame = 3 // CAN FD Extended Format:
                        //      frame_id is 29-bits
}

table CanFrame {
    frame_id:uint;      // CAN Message ID.
    payload:[ubyte];    // Payload of the CAN frame, covered by DLC. The length
                        // of payload content should match values as defined by
                        // CAN DLC spec (for example):
                        //      Standard/Base frame: 0...8
                        //      Extended frame: 0...8,12,16,20,24,32,48,64
    frame_type:CanFrameType = BaseFrame;

    // CAN Frame Metadata
    bus_id:ubyte;       // CAN Bus ID (logical identifier).
    node_id:ubyte;      // ECU ID for the node _sending_ this Frame.
    interface_id:ubyte; // Interface ID of the node interface _sending_ this Frame.
    timing:Timing;      // Timing of the frame.
}

union FrameTypes {
    CanFrame:CanFrame,
}

table Frame {
    f:FrameTypes;       // Workaround as Vectors of Unions is not fully supported.
}

table Stream {
    frames:[Frame];     // Vector of Frames.
    node_uid:uint;      // UID of the node which sends this Stream. The node can
                        // use this field to detect if it is receiving a Stream
                        // which it had previously sent (and take appropriate
                        // action).
}

root_type Stream;
file_identifier "SFRA"; // Stream of FRAmes.