USR IOT USR-CANET200 - CAN Data Transparent Transmission Protocol

USR-CANET200-User-Manual Technical Support: h.usriot.com
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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,