Protocol Mode - Ebyte E810-DTU User Manual

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4.2.3 Protocol mode

The data conversion format of E810-DTU(CAN-RS485) module is as follows. Each CAN frame contains 13 bytes,
and the 13-byte contents include CAN frame information + frame ID + frame data.
CAN frame CAN frame
Frame information: 1 byte in length, used to identify some information of the CAN frame, such as type, length, etc.
FF
BIT7
FF：The identification bits of the standard frame and the extended frame, where 1 is an extended frame and 0 is a standard frame.
RTR：The identification bits of the remote frame and data frame, 1 is the remote frame and 0 is the data frame.
N/C：value is 0，cannot write 1.
D3～D0：The data length bit identifies the data length of the CAN frame.
Frame ID：The length is 4 bytes, the standard frame valid bit is 11 bits, and the extended frame valid bit is 29 bits.
High
byte
12h 34h
The above is the extended frame ID number.
0x12345678 is the format
Frame data：The length is 8 bytes, and the effective length is determined by the value of D3~D0 of the frame information.
DATA8
11h
The above is the 8 bytes valid data format.
DATA8
11h
The above is the 5 bytes valid data format.
For example：
Below is the extended frame，frame ID is 0x11223344，8 bytes valid data format.
（11h,22h,33h,44h,55h,66h,77h,88h).
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CAN frame
RTR N/C
byte
Low
56h 78h
22h 33h
22h 33h
CAN frame
N/C D3
High byte
00h 00h
The above is the standard frame ID number.
0x123 is the format
44h 55h
44h 55h
E810-DTU(CAN-RS485) User Manual
CAN frame
D2 D1
BIT0
Low byte
01h 23h
DATA1
66h 77h
DATA1
00h 00h
D0
88h
00h
17