AN1105 datasheet(32/100 Pages) STMICROELECTRONICS

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ST7 pCAN PERIPHERAL DRIVER

example! You can implement a buffer for each message type, a FIFO of standardized buffers etc.

Note 2: For safe programming, you should systematically verify whether the buffer is not currently being

read/written, and whether the buffer is really free before further processing.

(For specific information concerning the buffer data type, see Section 2.1.5.1 "Data-type Var-

iables").

Remember that one of the received messages may switch off the cell. Once a message is re-

c e i v ed, w e hav e t o c hec k to s ee i f i t i s thi s one . T h i s i s don e us i ng the

CAN_Data_Reception_Notification function.

CAN_Data_Reception_Notification Function

The CAN_Data_Reception_Notification function is the following prototype in can_custom.c.

The routine is called once the data in a data frame has been saved in the buffer passed in the

CAN_Request_Buffer function. Before calling the CAN_Switch_on function, refresh the

watchdog (See “Functions” on page 21, CAN_Switch_Off for further explanation). Let’s add

the following code:

void CAN_Data_Reception_Notification(u16 message_ident)

{

if (message_ident==0x6000)//checks the id of message

{

if (reception_buffer.CAN_msg_data[0]==0xFF)//Checks the content of data

{

CAN_Switch_Off(BUS_WAKEUP);

}

So, if the first data byte of the message whose identifier is 0x600 contains 0xFF, the cell will

switch off and wait for a bus Wake-Up command (a dominant bit).

CAN_Remote_Reception_Notification Function

When a remote frame is received, we must send a message with a 0x500 ID. Let’s do it inside

this routine which is called each time a remote frame is received.

The message does not exist yet. As for the buffer, we have to create a variable

message, by

adding the following code in the file:

////////////////////////////////////////

//VARIABLES/////////////////////////////

////////////////////////////////////////

CAN_Buffer message_to_send_on_request= /

{0x5000,DLC5,{0x00,0x01,0x02,0x03,0x04},CFALSE,CFALSE};

AN1105 датащи(PDF) 32 Page - STMicroelectronics