Re: Scan-tool with PIC

Does VW follow ISO-9141 or do I have an old version? If you read the
spec dated Dec 1996 it shows the header to consist of the tester
sending 33 at 5 bits per second, response from ecu of 55 (timing sync)
08 (KW 1) 08 (KW2) and then the tester responds with the inverse of KW
2 (F7 hex). The ecu then sends the inverse of the address (CC) and it
is ready for the first message request. The ECU should respond in 25 -
50 mSec.

I'm wanting to try this also but am using Motorola's new cheapie micro
controllers.

> Message: 1
> Date: Wed, 04 Dec 2002 15:48:29 -0000
> From: "acetoel" <Nik@...>
> Subject: Re: Scan-tool with PIC
>
> Hi,
> I'm making a Scann tool with PIC for VW. I made my own interfase,
> which works okey, and succesfully receive 0x55 0x01 and 0x8A from
> the ECU. Then I have some problems with timming. I don't know how
> much time do I have to wait after sending the ACK byte and so on.
> Could you provide this info (time between bytes and so on) that you
> have on the ISO documents. I can send you the diagram of my
> interfase which works Ok with a PIC16F73. Thank you
> Ezequiel
> nik@...

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Received on Thu Dec 05 08:06:57 2002