I have some basic questions.
Purpose:
Obtain the RPM value off of Chrylers CCD bus using ODB_I
What I've done
I've written a VB program to interface with the RS232 port using the API.
Researched the CCD bus -- twisted pair with one wire (+), the other wire (-) -- running at 2.5 volts
I know the baud rate of the CCD bus signal.
What I think I Understand.
I believe (??) the signal is part of (i.e. rides on) the voltage. Hence the signal -- RPM of interest -- needs to be extracted from the voltage.
Still doing research on the header and trailer bytes (or bits) and the identifying byte which will indicate that the RPM is the next data in sequence
Questions (What I don't understand)
1) How do I connect the CCD bus to my RS232 port.?
2) How do I go about separating the signal from the voltage so I don't kill my computer?
3) How do I determine whether the CCD bus is putting out an analog or digital signal?
If analog I know I'll need an analog to digital converter.
4) Anything else that I should know but haven't asked.
Thanks
David