I still haven't found what I'm looking for. And I've search the web using
google and other search engines. So I though I would break down and ask a
question to you friendly people.
So if you know the web link please post it here. I'm looking for the
protocol for J1850 for a Ford escort. And don't reply with the SAE website.
5 DATA LINK LAYER DETAILS
This section defines the requirements on the following Data Link Layer
a. Addressing Strategy
b. Network Access and Data Synchronization
c. Frame Elements and Structure
d. Error Detection
e. Error Response
Here is another small slice.
5.3 Network Elements and Structure
The general format is:
idle, SOF, DATA_0, ..., DATA_N, CRC, EOD, NB, IFR_1, ..., IFR_N, EOF, IFS,
The preceding acronyms are defined as follows:
idle: Idle Bus (occurs before SOF and after IFS)
SOF: Start of Frame
DATA: Data bytes (each 8 bits long)
EOD: End of Data (only when IFR is used)
CRC: CRC Error Detection Byte (may occur in IFR as well)
NB: Normalization Bit (10.4 Kbps only)
IFR: In-Frame Response Byte(s)
EOF: End of Frame
IFS: Inter-Frame Separation
I think this is as close as you are gonna get to Ford specifics on the net...
Someone would have to be motivated to bootleg Ford's implementation, and why
would they do that? Maybe 10 years ago.. now most see dollar signs.. same as
Using the Intel specs and an OBDII scanner, you SHOULD be able to eventually
Unless you want even lower level stuf.. but they arent going to define
commodity stuff like the CRC algorythm.. just show you what physical layer
Looks like bit definition is NRZ1, (Start of Bit=Transition).. sorta
surprising to me but then I never messed with PWM.
cod opined in
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