Diacom plus on Pentium laptops

steve ravet steve at imes.com
Tue Jul 28 19:43:25 GMT 1998


mrvette wrote:
> 
> Am I illiterate here on the latest and greatest?  I somehow thought that UART's
> solved that problem long ago....?    GENE

You'd think so...  The problem is that Diacom has to talk to P4 ECMs,
which is similar to RS-232 except a PC can't get exactly the right baud
rate.  Close enough, though.  It also has to talk to C3 ECMs, which
aren't at all like RS-232.  So even though the serial port could be used
for P4 it wouldn't work for C3.  So the implement a software UART. 
Which is very timing dependant, and hence runs funny under windows.

Ludis Langens did have a clever idea for using a serial port to talk to
both, maybe someone should forward the idea to Diacom...

--steve

> 
> TWong29770 at aol.com wrote:
> >
> > I so far found that I can communicate with earlier ECM's.  However I still
> > cannot talk to a 94 GM truck PCM, or my 95 OBD1 PCM in my Corvette.  I can
> > talk to both PCM's while using a 486 slower computer.  Rinda tells me it's the
> > clock speed of the CPU's conflicting with the communication rate of the
> > ECM/PCM's.
> >
> > Weird....
> >
> > Tom

--
Steve Ravet
International Meta Systems
http://www.imes.com
steve at imes.com



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