ZLG CANFDNET-400U, Руководство пользователя

Страница: 37 / 47

CANFDNET-400U
High-performance Four-channel CANFD Bus-to-Ethernet Converter User Manual
©2021 Guangzhou ZLG Microelectronics Technology Corp.,Ltd.
34
User Manual
Frame ID0 ID.7 - ID.0
Data 1
Segment
marker
Segment type Segment counter
Data 2 Character 1
Data 3 Character 2
Data 4 Character 3
Data… Character…
Data 62 Character 61
Data 63 Character 62
Data 64 Character 63

Fragmented packet flag: indicates whether the packet is a fragmented packet. A
0 for this bit indicates a separate message, while a 1 indicates a frame within the
segmented message.

Segment type: indicates the first, middle or last segment. Table 4.27 lists the
value definitions.
Table 4.27 Segment type bit values
Bit value Meaning Description
0 First segment
If the segment counter contains the
value 0, this is
The first segment in a series of
segments.
1 Middle segment This is an intermediate segment
2 Last segment Mark the last segment

Segment counter: The flag of each segment indicates the sequence number of
the segment in the entire message. The value of the counter is the segment
number. This will allow you to verify whether any segments are missing when
receiving. A total of 5 bits are used, and the range is 0-31.
4.4.2 Conversion Methods
During the conversion from the serial port side to the CAN (CNAFD) side, the
converter will only perform the conversion after receiving a complete and correct Modbus
RTU.
Table 4.28 shows the CAN mode conversion, and Table 4.29 shows the CANFD
mode conversion. The address field of the Modbus RTU protocol is converted into ID0 of
the frame ID in the CAN message. The flag does not change during the frame conversion.