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5.4.5.1
CAN Transmission data use case
In the CAN SPY or SLAVE mode, any of the 100BASET1_SPY CAN port can act as transmitters accord-
ing with the CAN protocol communication. In this case, a specific Ethernet frame received from any
of the Gigabit ports will be sent through a specific CAN Port. The following table shows the structure
of the Ethernet CAN Transmission data frame used for this purpose:
Note:
The
Direction
field specifies if the frame is being received (Direction 0x01) or transmitted
(Direction 0x00).
Note:
The
Message Type
field specifies if the frame is used like a Data Frame (0x00) or a CAN Event
Frame (0x01). The Ethernet frame format used in the Data Frame case is described in the table
above. The purpose of the CAN Event Frame is described in the next section.
Note:
The value of the
Port Number
depends on the CAN port where the user wants to send the CAN
frame. Its values can be the following:
Port
Value
CAN A
0x01
CAN B
0x02
CAN C
0x03
CAN D
0x04
CAN E
0x05
Note:
The value of the
ID
will determine if the CAN frame is standard (lower than 0x0FFF) or extend-
ed (higher than 0x07FF).
Note:
According with the CAN/CAN-FD specification, only 16 Lengths can be set. The values in hexa-
decimal that can be used in the
Length
field are the following:
Length (bytes)
Value in Length field (hexadecimal)
From 0 to 8
0x00 to 0x08
12
0x0C
16
0x10
20
0x14
24
0x18
32
0x20
48
0x30
64
0x40
Field Name
No. Of Bytes Value
Destination MAC Address
6
FF:FF:FF:FF:FF:FF
Source MAC Address
6
It depends on the source Ethernet Adapter
Ethertype
2
0x2085
Direction
1
0x00 (TX Frame)
Message Type
1
0x00 (Data Frame) or 0x01 (CAN Event Frame)
Port number
1
From 0x01 to 0x05
CAN ID
4
CAN ID
Length
1
In bytes
CAN Payload
0 to 64
Its length depends on the Length field