B&B Electronics Command Response Protocol HVD100A3 - Manual (Page 27)

HDV100A3 Command & Response Manual-1306cr 23
B&B Electronics -- 707 Dayton Rd. -- PO Box 1040 -- Ottawa, IL 61350
PH (815) 433-5100 -- FAX (815) 433-5104
Transmit Data to J1939 Bus
Byte
Number Byte
Value Function
1 01 Start of frame
2 06 Control bytes
3 02 ID byte 1 = J1708 message
4 02 Function byte 02 transmit message
5 XX MSB of arbitration field (J1939 priority bits)
6 XX MSB-1
7 XX MSB-2
8 XX LSB of arbitration field (J1939 source address)
9 DD Number of data bytes
DATA From 0 to 8 bytes
CS Checksum
Set Mask
Function code 04 set mask. The mask is applied to ALL filters. The mask is
32 bits long. The last 3 bits are not used and must be set to zero. This mask
covers the 29-bit arbitration field. To use the filter function, the mask must
be set. The mask determines what position(s) will be tested and matched to
the incoming message. If a 1 is set in a particular position, that position will
be tested. It will be “and” with any active filters to determine if the message
will be passed to the PC side. Any position marked with a 0 is a “don’t care”
position and will pass all data in that position. There is a form on page 33
that helps set up the mask for the arbitration field.
Byte
Number Byte
Value Function
1 01 Start of frame
2 06 Control bytes
3 02 ID byte 02 = J1939
4 04 Function byte 04 set mask
5 XX MSB of arbitration field (J1939 priority bits)
6 XX MSB-1
7 XX MSB-2
8 XX LSB of arbitration field (J1939 source address)
9 00 Number of data bytes
10 CS Checksum