can_device

Description

SIM_INTERFACE(can_device) {
        void (*receive)(conf_object_t *obj, can_frame_t *frame);
};
#define CAN_DEVICE_INTERFACE "can_device"

The can_device interface is implemented by CAN controllers. The receive function is called by can-endpoint to pass CAN frame from other can-endpoint to the connected CAN controller.

The CAN frame is expressed by the frame parameter, which is a pointer of can_frame_t. The following is the details of can_frame_t:

• Standard Format:
  Arbitration Field(11bit_ID+RTR)+Control Field(IDE+r0+DLC)
• Extended Format:
  Arbitration Field(11bit_sID+SRR+IDE+18bit_eID+RTR)+Control Field(r1+r0+DLC)

Above are the Arbitration Field and Control Field of the physical Standard frame and Extended frame. But the can_frame_t only focus on the logical meanings of such fields and tries to adapt different CAN controllers:

• identifier: For Standard frame, 11bit_ID should be put in identifier[10:0];for Extended frame, 11bit_sID should be put in identifier[28:18] and 18bit_eID should be put in identifier[17:0].
• extended: There isn't IDE in can_frame_t, instead, extended is used to indicate if the frame is Extended frame or Standard frame.
• rtr: There isn't SRR in can_frame_t for Extended frame, instead, rtr is used to indicate if the frame is a remote frame or not. Here we don't care whether the frame is Extended frame or Standard frame.
• data_length: The data_length contains the arithmetic value of the DLC.
• data[CAN_DATA_MAX_NUM]: This is the data field of Date frame.
• crc: This is the crc field of a CAN frame.

typedef struct {
        /* arbitration field */
        uint32 identifier;
        bool extended;
        bool rtr;
        /* control field */
        uint8 data_length;
        /* data field */
        uint8 data[CAN_DATA_MAX_NUM];
        /* crc field */
        uint16 crc;
} can_frame_t;

Execution Context

Cell Context for all methods.