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7 Layer 2 Communication Mode (11/29 bit ID)
7.1 [BFM #100 to #399] Sending/Receiving Pre-defined Layer 2 Messages
62
FX
3U
-J1939 User's Manual
*1.
For details, refer to "When transmitting messages" and "When receiving messages" mentioned shortly
hereafter.
*2.
These BFM will be stored into the Flash ROM when the save command is executed.
For save command, refer to Section 5.5
1. When transmitting messages
The CAN-ID, Status/Control Flags and data bytes of each message are as follows.
1) CAN-ID
The destination of the message is specified by the 32 bit CAN-ID parameter. Valid values are as follows:
- 11 bit mode: 0 to H000007FF
- 29 bit mode: 0 to H1FFFFFFF
For function mode, refer to Section 5.4
2) Status/Control Flags
Setting is as follows.
*3.
Bit 12 specifies whether strict DLC check is used for RTR frames. If Bit 12 is OFF, only the CAN-ID
of an inbound RTR frame is checked for a match with a user message. If Bit 12 is ON, the CAN-ID
and the DLC of the RTR frame must match the user message to cause a response. Otherwise,
BFM #1270 to #1272 flag to be set. Bit 15 and Bit 12 can not be set ON at the same time.
*4.
Bit 15 defines if the message is transmitted as a data frame (Bit 15 OFF) or a Remote Transmit
frame (Bit 15 ON). Bit 15 and Bit 12 cannot be set ON at the same time.
3) Data bytes
Store the data to transmit. The data length of the transmit data is set by DLC.
BFM #387
CAN-ID 42 LW
*1
11/29 bit CAN-ID low word
L
ay
er
2
mess
ag
e 42
HFFFF
R/W
*2
BFM #388
CAN-ID 42 HW
*1
11/29 bit CAN-ID high word
HFFFF
R/W
*2
BFM #389
RTR/new/DLC
*1
Status/Control Flags
DLC
H0
R/W
*2
BFM #390
Data bytes
*1
2nd data byte
1st data byte
H0
R/W
-
BFM #391
4th data byte
3rd data byte
H0
R/W
-
BFM #392
6th data byte
5th data byte
H0
R/W
-
BFM #393
8th data byte
7th data byte
H0
R/W
-
BFM #394 to #399
Reserved
-
-
-
High Byte/Low Byte
Description
High byte
Bit 12
*3
ON: Strict DLC check for RTR
Bit 15
*4
OFF: Send data frame
Bit 15
*4
ON: Send RTR frame
Low byte
Number of data bytes to transmit (K0 to K8)
*3*4
BFM No.
Name
Description
Message
No.
Initial
Value
Read/
Write
Stored to
Flash ROM
High Byte
Low Byte