Integration with CAN

CAN bus is a message-based protocol, designed specifically for automotive applications but now also used in other areas such as aerospace, maritime, industrial automation and medical equipment (got from wiki).

Protocol

Network can be easy integrated with CAN because the protocols of these networks are frame-based. CAN resides on the Data-Link Layer of the Network Model and represented with data unit as Frame. While the Network Layer operates through Routing Protocol (SARP) and Packet. Therefore, SARP will work over CAN Protocol 2.0B (specification with extended message formats).

The Data Length field of the Packet from SARP is equivalent with CAN Frame. The SARP Header part can be converted to CAN Extended Identifier (29 bit).

Frame structure

Part	Field name	Length (bits)		Description
Header	SACP	29	8	SACP Data Classifier
	SARP		16	SARP address information
	SATP		3	SATP flags
	Reserved		2	Must be set to 0x0
Length	Data length	4		The length of data in bytes
Payload	Data	0-64		Max 8 bytes

Note

The fields Start of Frame, Cyclic redundancy check and End of Frame are not presented in this structure because the CAN protocol has own implementation for its.

SACP (8 bits)

The Channel and Data Classifier for Control Protocol (SACP).

SARP (16 bits)

The address information that contains Source and Destination IDs for Routing Protocol (SARP).

SATP (3 bits)

The Segmentation, Final and Acknowledgment flags for Transport Protocol (SATP)

Data length (4 bits)

The length of Payload part in bytes. The Frame can be empty (without Payload). In this situation Data length=0x0 and Payload is not presented in the Frame. The maximum size of Payload part is 8 bytes.

Data (0-64 bits)

The Payload data for Transport Protocol (SATP).