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Re: Any other GM comms speeds?



I think, more specifically, it's ODB-II. What Malcolm is describing sounds
like the initial wake-up that OBD-II needs to initiate the ISO protocol.

A little taster:

ISO does a wacky initialisation sequence:
To ECU: 0x33 at 5 bps (This is "Address" NB with start and stop, takes 2
secs!)
>From ECU 0x55 at 10.4k ("Synchronization")
>From ECU 0x08 0x08 OR 0x94 0x94 at 10.4k ("Keywords")
To ECU 1s complement of last "Keyword" (ie 0xF7 or 0x6B)
>From ECU 1s complement of "Address" (ie 0xCC)
Address is transmitted on both K and L, all further communication is on L
only. If Keywords are 0x08 then gaps between messages are minimum 25ms, if
Keywords are 0x94, gaps can be 0.

(Info from Nick Reilly).

P.S. Hey Malcolm, did you ever fathom out the ALDL protocol on the Lotus
Carlton? I roughly disassembled the Lotus Carlton ECU code from the .bin
that was in the incoming directory of the EFI site. I could now, probably
set up a FreeScan conversation with the Carlton's ECU but I have no
DataStream information.

Andy.
------------------------------------------
Andy Whittaker
Chester, England.
Email: mail@andywhittaker.com
Web: http://www.andywhittaker.com/
ECU Stuff: http://www.andywhittaker.com/ecu/

----- Original Message -----
From: "Malcolm Robb, LC 0112G" <Webmaster@lotus-carlton.fsnet.co.uk>
To: <gmecm@diy-efi.org>
Sent: Thursday, June 15, 2000 10:22 AM
Subject: RE: Any other GM comms speeds?


> Yup - Most European Vauxhalls and Opels use Bosch Motronic ECU's, and
their
> baud rate is 9600. Worse than that, they actually need to receive a 5 (yes
> five) baud 'enable' character before they will talk at 9600. All the ECU's
> in the car (Engine ECU, alarm, gearbox, digital dash, trip computer
> etc,etc) are connected via the ALDL port, and the 5 baud character is used
> to select which device you want to 'talk' with
>
> The only European Vauxhall/Opels that I am aware of that use the GMP4 are
> the Lotus Carlton/Lotus Omega (the best car the world has ever seen
:- ) ),
> and the Monteray 3.2 V6 (a Range Rover type thing). Both of these use the
> standard 8192 baud comms.
>
> I have the Vauxhall/Opel cartridge for the Tech1 scan tool. If you can
tell
> me which car the ECU originally came out of I can have a quick poke about
> to see what the Tech1 tries to do to initiate comms.
>
> Another possibility is that the previous owner of the ECU modified it so
> that it could be used directly with a PC's COM port !?
>
> Cheers,
> Malcolm Robb, LC 0112G
>
> -----Original Message-----
> From: Ross Myers [SMTP:ponty@axis.jeack.com.au]
> Sent: Wednesday, June 14, 2000 10:45 AM
> To: GM ECM List
> Subject: Any other GM comms speeds?
>
> Hi all,
>
> I've been playing around with a 16188269 ECU (Picture is at my web page),
> these are strange in that they have no Flash or Memcal, it was built in
> 1995. The CPU seems to match the HC11 'E' series so I guess it may have
20K
> or so of OTP.
> Anyway, I'm want to dump the memory contents out via a Mode2 request, only
> I
> cannot get this thing to talk to me!!, the wiring diag shows a
> Bi-directional Serial Data line on the ALDL, but no matter what I.D byte I
> use for a Mode1 request I get no response (I've tried $01 - $FE).
> First thing, the ECM has no 64606 I.C fitted, instead the serial data runs
> through transistor/resistor combinations to the CPU Rx/Tx pins.
> Secondly, this ECU is used in the U.K on Opel & Vaxhuall cars as well.
> So, did GM use another speed other than 8192 for bi-directional comms?.
>
> Thanks,
> Ross Myers
> Melbourne, Australia
> E-mail : ponty@axis.jeack.com.au
> Stuff : www.jeack.com.au/~ponty


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