AN1105 datasheet(42/100 Pages) STMICROELECTRONICS

номер детали	AN1105

подробное описание детали	ST7 pCAN PERIPHERAL DRIVER

PDF	100 Pages

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производитель	STMICROELECTRONICS [STMicroelectronics]

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ST7 pCAN PERIPHERAL DRIVER

FIFO Management Structure

In the main structure, we find:

typedef struct {

u8 fifo_size;

FIFO_Object* first_object;

FIFO_Object* last_object;

CAN_Bool isinuse;

} FIFO;

The structures shown here look more like parts of a chained-list. Indeed, the data-type imple-

mented is not pure FIFO, but simulates the behaviour of a real queue.

Three

FIFO_Objects are statically defined and linked together in a circular way (in the

CAN_First_Init routine). One FIFO variable is also defined and initialized in the meantime (cf.

in can.c):

//Transmission queue

static FIFO CAN_transmit_queue;

static FIFO_Object CAN_queue_object_1;

static FIFO_Object CAN_queue_object_2;

static FIFO_Object CAN_queue_object_3;

The maximum size of the queue is therefore 3.

To simulate in-queuing/out-queuing, you only have to verify that the size limit will not be over-

ridden, and update the fields in the FIFO structure.

The “isinuse” Boolean is checked each time the variable is accessed to prevent read/write

conflicts.

AN1105 датащи(PDF) 42 Page - STMicroelectronics