AN1105 datasheet(41/100 Pages) STMICROELECTRONICS

номер детали	AN1105

подробное описание детали	ST7 pCAN PERIPHERAL DRIVER

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ST7 pCAN PERIPHERAL DRIVER

Figure 18. CAN_Transmit_Request Flowchart

3.2 INTERNAL FUNCTIONS AND DATA TYPES

3.2.1 Internal Data Types and Variables

3.2.1.1 Transmission FIFO

To avoid losing data, messages to be sent are queued in a 3-message length FIFO prior to

transmission.

Queue Unit

In fact, no physical CAN_Message structure is put into the queue. The objects handled are de-

scribed below:

typedef struct FIFO_Object

{ CAN_Message* message;

struct FIFO_Object* next_object;

struct FIFO_Object* preceding_object;

}FIFO_Object;

Only a pointer to the message appears in the structure, to avoid complex data manipulations.

The two following fields are pointers to other FIFO_Object structures.

RUN = 0

Begin

FIFO full?

No message?

message_to_send.buffer_rw=CTRUE

message_to_send.buffer_rw=CFALSE

Returns

CAN_TRANSMIT_FAILURE

Returns

CAN_FIFO_FULL

message_to_send.buffer_rw=CFALSE

Returns

CAN_TRANSMIT_FATAL

Returns status

(Result of CAN_Fill_Transmission_Buffer)

CAN_Fill_Transmission_Buffer

message_to_send.buffer_rw=CFALSE

CAN_In_Queue

(msg_to_send)

AN1105 датащи(PDF) 41 Page - STMicroelectronics