CANFDNET-400U
High-performance Four-channel CANFD Bus-to-Ethernet Converter User Manual
©2021 Guangzhou ZLG Microelectronics Technology Corp.,Ltd.
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User Manual
indicates a remote frame. It can only be 0 for CANFD;
EDL: CAN and CANFD identifier. 0 indicates the CAN, while 1 is indicates the
CANFD;
BRS: baud rate switching enable flag. 0 indicates no rate conversion, while 1
indicates variable rate conversion, only valid for CANFD; this bit should be 0 in CAN;
DLC3-DLC0: identifies the data length of the CAN (CANFD) message.
The length of the
frame ID
is 4 bytes. The valid bits of the standard frame are 11 bits,
and the valid bits of the extended frame are 29 bits.
Table 4.21 Frame ID example
Standard frame ID 0x12345678
Standard frame ID 0x3FF
0x12
0x34
0x56
0x78
0x00
0x00
0x03
0xFF
When the
frame data
is converted in CAN format, the length is fixed to 8 bytes. In
CANFD format conversion, the length is fixed to 64 bytes. The effective length is
determined by the value of DLC3-DLC0. When the valid data is less than the fixed length,
add 0 to the fixed length. As listed in Table 4.22, it is the representation of 6-byte valid data
during CAN format conversion. The last two bytes are filled with 0s.
In this mode, pay attention to the serial data format in strict accordance with the fixed
byte format. Table 4.23 and Table 4.24 shows the reference examples for CAN mode
conversion. It is similar in CANFD mode, except that the frame data is fixed 64 bytes. In
the conversion, first ensure correct frame information. The data length must be correct;
otherwise, no conversion will occur.
Each frame of CAN format conversion is fixed to 13 bytes, while each frame of
CANFD format conversion is fixed to 69 bytes. If it is insufficient, it must be filled with 0.
The serial data satisfying the fixed byte format in the same serial data frame corresponds
to a CAN (CANFD) message. Serial data frames that are less than fixed bytes will not be
converted. Therefore, make sure that the serial data frame being converted is aligned with
the corresponding fixed byte. If the number of fixed bytes is insufficient, a timeout of about
100 ms will occur. If fixed bytes of data have not been received after the timeout, the
previously received data will be cleared.
In the conversion of serial frames to CAN (CANFD) messages, if the data format of a
certain segment of fixed byte in the serial data frame aligned with fixed bytes (fixed 13
bytes for CAN and 69 bytes for CANFD) is not standard, fixed byte lengths will not be
converted, and subsequent data will be converted. If some CAN messages are missing
after conversion, check whether the fixed-byte-length serial data format of the
corresponding message is not the standard format.
Table 4.22 Data frame
CAN format conversion 6-byte valid data representation
0x11
0x22
0x33
0x44
0x55
0x66
0x00
0x00
Table 4.23 Example of converting CAN formats to extension frames
The following example is a CAN extended data frame. The ID is 0x12345678, which
