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--- en:hardware:avr-can:can-functions [2010/04/05 12:57] – created mikk.leini
+++ en:hardware:avr-can:can-functions [2020/07/20 12:00] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+====== CAN-Functions ======
+====The can_t Structure====
+CAN communication between the used CAN boards is (on the programming
+level) accessed through the use of a structure named can_t which is deﬁned in
+"can.h". The structure can_t consists of variables that can be written to prepare a
+message for sending or read to process a received message. Here is an overview
+of the variables of this structure:
+<code c>
+Structure  can_t:
+	uint32_t        id: //  message  ID
+	struct flags
+	int rtr: //  remote-transmit-request-frame
+	int extended: //  extended  ID  ?
+	uint8_t length: //  number  of  data  bytes
+	uint8_t data[8]: //  message  data
+</code>
+====Functions for CAN Communication====
+The header ﬁle "can.h" declares various functions necessary for CAN communi-
+cation. The CAN library is open source. The following functions are sufﬁcient
+for basic communication:
+**Initialization of the CAN interface, setting of the baud rate:**
+<code c>
+extern    bool can_init(can_bitrate_t  bitrate);
+//  Check  if  a  CAN  message  has  been  received  (function  returns  TRUE  or  FALSE):
+extern    bool can_check_message(void);
+//  Retrieving  a  message  out  of  the  receive  buffers  of  the  CAN  controller:
+extern    uint8_t      can_get_message(can_t  *msg);
+//  Sending  a  message  over  the  CAN  Bus:
+extern    uint8_t      can_send_message(const  can_t  *msg);
+</code>