USR IOT USR-CANET200, User Manual

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USR-CANET200-User-Manual
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2.2.4.CAN data transparent transmission protocol
1.Byte conversion
CAN data transfer to Ethernet data: Transfer CAN ID and data to 13 bytes network data.
2.Frame information
88h
Frame information length is 1 byte and is used to identify some frame information such as: frame type, frame
length.
Bit7 Bit0
FF
RTR Reserved Reserved B3 B2 B1 B0
 FF: Identifying bit to identify standard frame and extended frame, 1 is extended frame and 0 is standard
frame.

RTR: Identifying bit to identify remote frame and data frame, 1 is remote frame and 0 is data frame.

Reserved: Reserved bit needs to be 0.

B3~B0: Data length bit to identify CAN frame length.
3.Frame ID
Four bytes, high-order bit is former and low-order bit is latter.
12h 34h 56h 78h
Extended frame ID: 0x12345678
00h 00h 01h 23h
This ID can be standard frame ID or extended frame ID(Standard frame ID or extended frame ID is identified by
frame information):
 Extended frame ID: 0x00000123

Standard frame ID: 0x0123
4.Frame data
Eight bytes. Effective length is expressed by B3~B0 of frame information and insufficient bits will be supplied by
00h.
For example:
CAN to Ethernet: CAN side transmit data(Frame format: extended frame; frame type: data frame; ID: 12345678;
data: 12 34 56 78 00) and Ethernet side will receive: 85 12 34 56 78 12 34 56 78 00 00 00 00. 0x85 means frame
format is extended frame, frame type is data frame and data length is 5;
‘ 12 34 56 78 ’ are CAN ID; ‘ 12 34 56 78 00
00 00 00 ’ are data with effective length 5 and the rest bits are supplied with 0.
Ethernet to CAN: Ethernet side transmit: 05 00 00 06 78 12 34 56 78 00 00 00 00. 0x05 means standard frame,