FC6A S
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OMMUNICATION
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ANUAL
FC9Y-B1730
8-3
8: J1939 C
OMMUNICATION
Message
CAs use the data frame in the CAN extended frame format that holds the 29-bit CAN ID to exchange messages. The CAN ID is
composed of the priority, PGN, and source address. The PGN is composed of the EDP, DP, PDU Format (PDUF), and PDU Specific
(PDUS).
PDU 1 format
When PDUF is 00h to EFh, the PGN is defined in the format called the PDU1 format. The PGN is defined with EDP, DP, and
PDUF, and it is handled as a PGN for one-to-one communication. At this time, the destination address is stored in the PDUS.
However, when the PDUS is specified as 255 (global address), the PGN is handled as a broadcast PGN, not as one-to-one
communication.
PDU 2 format
When PDUF is F0h to FFh, the PGN is defined in the format called the PDU2 format. The PGN is defined with EDP, DP, PDUF,
and PDUS, and it is handled as a PGN for broadcast communication.
Since the data that can be stored in the CAN data frame is a maximum of 8 bytes, when the PGN data is 9 bytes or longer,
messages are split into 8-byte packets and exchanged as multi-packet messages.
Overview of J1939 Communication Supported by the CAN J1939 All-in-One Type
The CAN J1939 All-in-One Type can connect to a J1939 communication network as an ECU that has one CA. It is compatible with
the network management function that manages addresses between CAs so address conflicts can be resolved and dynamic
addresses can be assigned.
S
O
F
29 Bits
CAN ID
Message
6 Bits
Control
18 Bits
PGN
8 Bits
Source Address
8 Bits
PDU Format
8 Bits
PDU Specific
8 Bytes
Data
16 Bits
CRC
3 Bits
Priority
1 Bit
EDP
1 Bit
DP
2 Bits
ACK
7 Bits
EOF
R
T
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S
CAN
CAN Port
FC6A Series MicroSmart
(CAN J1939 All-in-One Type) (ECU)
ECU
ECU
CA
CA
CA
CA