Diacom, OBDII interface

[thomas walter x5955]

> I hate posting stuff from old memory, but I can't find my J1850 (OBD-II) 
> article. So here's what I remember about it:  it supports two data rates, I 
> think 1MB/s and 2MB/s.  It is not even close to RS-232 regardless of the 
> data rate, so it'll never hook to a serial port.  Harris (and maybe others) 
> make a two chip set for it, one is the basic data framer, the other is an 
> 8152 clone with OBD-II intelligence built in.
> 
> Steve Ravet
> sravet at bangate.compaq.com


Might be of interest, in the latest Motorola Databook, Analog/Interface
IC's Device Data [Q4/95 DL128 REV5] is a datasheet for the MC33199

MC33199:  IS0 9141 Serial Link Driver.

The MC33199D is a serial interface circuit used in diagnostic applications.
It is the interface between the microcontroller and the special K and L
Lines of the ISO Diagonositic port.

The MC33199 has a unique feature which allows transmission baud rate
up to a 200k baud.

Now do NOT get all excited, there is NO protocols listed! This is
just an interface circuit for the automotive use. Just a general
FYI for those who might be looking for an interface chip.
[Would someone with the SAE book please confirm if ISO9141 is
part of the J1850 standard?]


Oh there are some other intersting automotive chips listed,
but somehow the MC145050 A/D chips were left out of the A/D
section!!! Yes, chips are alive and selling well... but those
and other chips were left out of the databook. ;-(
[10bit A/D with 8 channel MUX. priced around $5.00]


Other tidbits... In Design News (10-9-95):

"Modules communicate via the Ford-proprietary Standard Corporate
Protocol (SCP), which complies with SAE's J1850 industry standard."
""We have over 200 Signals that go between 10 modules" says Young
[Lincoln-Mercury Project Design Enginee Susan Young]"

"General Motors spent over $2billion onn development and testing
to comply [with OBD-II requirements]"

Cheers,

Tom Walter