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Thread: 1997 F-Body ECM

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  1. #32
    Fuel Injected!
    Join Date
    Jan 2019
    Location
    Canada
    Posts
    477
    looks like great progress. For me, I have set the download aside for a bit. I have run into problems with understanding the queue of messages. In code from the '97 processor there is a scheme for some sort of FIFO. This lets reply from requests complete before working through the next request. I believe it is in that code where problems exist for me. It looks like one location is in normal circumstances set to $0. When a reply to a request is lengthy, one reply is sent out each time the subroutine is called. This takes place until the request has been serviced.
    This is also the code that looks after Mode $34 commands. It seems like mode $34 requests to the Tside do not set this location and thus will not process $36 command. When I figure it out, I will describe for the forum.

    In order to figure it out I have disassembled the Mode $19 command. It makes use of this extended service location. I have completed this now but need to go back and look at the service code that parses commands from the DLC.

    Great to see your progress!!
    Cheers,
    -Tom

    PS - Does anyone have information on Mode $19 ? I thought it would be part of SAE J2190 but is not listed there. Mode $18 is listed there and they seem very similar! What am I missing here?
    Last edited by Tom H; 05-01-2019 at 05:53 PM.

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