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XC161 Derivatives
Peripheral Units (Vol. 2 of 2)
Serial Data Link Module SDLM
User’s Manual
22-3
V2.2, 2004-01
SDLM_X, V2.0
22.2.1.1
Frame Format Basics
This chapter summarizes the basic definitions of the SAE Standard Class B Data
Communication Network Interface protocol.
The general J1850 frame format is defined as:
idle, SOF, DATA_0, …, Data_N, CRC, EOD, NB, IFR_1, …, IFR_N, EOF, IFS, idle
Figure 22-2
Standard Frame Types
summarizes the used abbreviations.
SOF
Header
Type 0 : No IFR
Data Field
Type 1 : Single Byte From A Single Responder
Type 2 : Single Byte From Multiple Responders
Type 3 : Multiple Bytes From A Single Responder
CRC
SOF
Header
Data Field
CRC
EOD
NB
ID
SOF
Header
Data Field
CRC
EOD
ID 1
IFS
IFS
...........
ID N
IFS
SOF
Header
Data Field
CRC
EOD
IFR Data Field
CRC
IFS
(when NB is active long)
NB
NB
EOD
EOF
EOD
EOF
EOD
EOF
EOD
EOF