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Thread: Newbie question about writing CAX files

  1. #1
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    Default Newbie question about writing CAX files

    Hello,

    I just recently got an EFILive setup second-hand from a good friend of mine, great product compared to other tuner packages!

    I am working on some homebrew custom code patches for the ECM for "hi-res" VE and spark maps.
    My question is about the memory offsets for CAX file variables. Is there a base offset used for each PCM type? I looked at several CAX files
    posted on the forum and noticed that their offsets exceed the max file size for the flash image (e.g. 1023F3 vs the max file size of 1MB (0FFFFF)).
    I also read mention that EFILive utilizes a ROM emulator for the flash files??? The ECM in question is a E40 with the 12604792 OS loaded on it.

    Thanks!

  2. #2
    Forum tyhee Site Admin GMPX's Avatar
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    E40 ECM has no offsets, everything is mapped 1:1 over the 1Mb flash range.
    Be REALLY careful with your 'code patches' unless you have some way to recover the ECM should you make a mistake and brick it.

    The 'ROM emulator' you mentioned might be the LS1 PCM based Road Runner, it was never offered for the E40.
    Need official EFILive help, please go here.
    For tuning support please post your questions on this forum (or other auto forums).
    Sorry if I don't respond to your PM, don't take it personal.


  3. #3
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    Quote Originally Posted by GMPX View Post
    E40 ECM has no offsets, everything is mapped 1:1 over the 1Mb flash range.
    Be REALLY careful with your 'code patches' unless you have some way to recover the ECM should you make a mistake and brick it.

    The 'ROM emulator' you mentioned might be the LS1 PCM based Road Runner, it was never offered for the E40.
    Thank you for the reply. I should've been clearer in my original response, sorry about that.

    Here is one of the example files I was looking at (not mine):

    https://github.com/Snipesy/Cruze/blo...r/12662377.cax

    Anyway, this is what I meant by offsets; The header of this .cax states that all offsets are +80000000h. Also there are address values over 0xFFFFF?
    Given it's for a E47 ECM and different OS then the one I'm working with at the moment, but I'm still confused. Plus the example file I was looking at
    for an E40 also had address over 0xFFFFF? Are all the addresses still mapped 1:1 in relation to the actual ROM length, regardless of ECM/OS?

    Thanks!
    Last edited by cdosys; October 4th, 2017 at 03:18 PM. Reason: forgot to add a link

  4. #4
    Forum tyhee Site Admin GMPX's Avatar
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    Ah yes, that E47 has very strange address mapping because of the CPU it uses (as does the Bosch E86).

    "Are all the addresses still mapped 1:1 in relation to the actual ROM length, regardless of ECM/OS?"

    For most of GM's gas ECM's yes this is the case. An E40 shouldn't have an address over 0xFFFFF as it is only a 1Mb flash chip that starts at zero in the address space.

    Cheers,
    Ross

    Need official EFILive help, please go here.
    For tuning support please post your questions on this forum (or other auto forums).
    Sorry if I don't respond to your PM, don't take it personal.


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