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Thread: Uber-easy DIY USB ALDL Cable

  1. #1
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    Uber-easy DIY USB ALDL Cable

    http://www.ebay.com/itm/Arduino-FT232RL-USB-to-Serial-Module-USB-to-TTL-level-USB-Cable-dupont-248-/260917151841?pt=LH_DefaultDomain_0&hash=item3cbfdf c861

    let me know if that link doesn't work, but it's what i bought a few weeks ago...

    anyways, this convenient little piece of hardware allows you to hook up to a 8192 baud ECM with 2 wires.... no resistors, no ICs, no diodes.... just two simple connections.

    and when it comes to homebrew hardware, simple is always good. just went and tested it on the MC, works great. also passes the tunerpro "test for cable" when unplugged from the car, not something i'm used to with my current cable.

    so anyways, before this i was using Parallax 28030 units, which are serial->USB adapters, so i converted the 8192 stuff(basically TTL?) to serial using a MAX232 circuit, then converted serial to USB using the Parallax 28030. ever built a MAX232 on proto boards? they're a pain. then soldering into the solder cups of a DB9 connector? also a pain.

    now, assuming you can get ahold of a male ALDL connector or just use the bare pins for whatever reason, you'll have 2 or 4 quick solder joints to make and then you're done. put it in a radioshack project box for like $3(since this came with it's own USB cable) and you're out the door with a USB ALDL cable for just under $12. attach a male OBD1 connector (for $15 plus shipping from ALDLcable.com, or i potentially have an overseas supplier that has a cable that can be used after some tweaking for a little under $9 shipped) and you have a fully functional and professional enough looking cable.

    sell it, use it, abuse it, whatever. :)

    anyways, tested at 8192 and it works flawlessly. since it uses the FT232RL, it should be a quality, long-lasting unit. i'd like to do a 160 baud test, but i don't want to try and dig out the 85 IROC ECM.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  2. #2
    RIP EagleMark's Avatar
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    Thanks Robert! Saw you looking into this awhile back. Got to be the cheapest way to make a cable on the net!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  3. #3
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    cheapest USB.... probably. and by a long shot as well. parallax 28030s are something like $18 shipped IIRC. then add in the MAX232...

    i'm more stoked about the fact that it's dead-simple to put together. my previous cables all went through the extravagence of a full MAX232, which was a total pain to put together and took forever compared to this.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


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    Fuel Injected! historystamp's Avatar
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    How do you set the baud rate?

    Robert

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    use Tunerpro. when making an ADS (or more recently, the ADX), you can simply choose to use an 8192 baud rate for a connection.

    IIRC, 8192 is the default rate in tunerpro anyways, so it won't really even be apparent unless you need to change it.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  6. #6
    Familiar with 1227747 and 16197427 PCMs

  7. #7
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    while some of them look similar, it doesn't look like the pins that are needed are available?

    if the RXD, TXD and ground pins are able to be connected to and it is a TTL to USB(or maybe UART to USB?) converter, then it should work.

    note: SHOULD. i researched the one i bought a bit before i pulled the trigger.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


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    RIP EagleMark's Avatar
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    OK that link was to much fun! Now all we need is a Uber Nerd to use one of these to flash a OBDII PCM?
    http://www.sparkfun.com/products/9555

    Robert in your spare time could you take pictures and links and ? For a formal writup on how to do the Cable? It would be great for the forum and I would convert it to our HTML pages. Many guys want to get into this but like us funds are limited nowadays and this is such a useful and cheap way to spend some time and get involved.

    This goes to anyone and everything who wants to contribute something here!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  9. #9
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    LOL, i can take 2 pics and write a paragraph, and that's about all that's necessary to explain how to make this type of cable. it's just that easy.

    that link though..... quite interesting. it would require converting from UART to USB(or UART to serial) to use it with a computer(could use the adapter i listed earlier from the looks of it), but since it uses ELM327 instruction sets, it can be used with tunerpro to do some basic logging at least...

    however, if the "large memory buffer" turns out to be large enough, it COULD be used to flash the PCM as well.... with the right software anyways, but that's always been the hard part.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  10. #10
    RIP EagleMark's Avatar
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    Darn software...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  11. #11
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    i can't write windows/DOS software worth a damn, otherwise i'd volunteer.... i only seem to work well with 68HC11/similar stuff.

    did some digging as well:

    http://www.obdsol.com/downloads/stn1110_vs_elm327.pdf

    ELM327 has 1.5KB of RAM... the STN piece has 8KB. it also has 4 times as much PROM space and has a processing speed 10X faster as well...

    IIRC, the big issue with attempting to use the ELM327 to flash the PCM was due to the ELM unit not being able to handle enough bytes of data at a time for transferring to the PCM.... with this much of a RAM bump, it seems like this at least has a shot at working. need to find someone who knows their OBD2 flashing protocalls to be certain.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  12. #12
    Fuel Injected! gregs78cam's Avatar
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    Good read here......But you already know that Robert........

    http://60degreev6.com/forum/showthre...similar-device






    Last edited by gregs78cam; 04-02-2012 at 09:06 AM.
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  13. #13
    This one

    http://www.sparkfun.com/products/8165

    looks like it's designed to be plugged into the other end of a USB cable. It has the TX and RX pins that you speak of. Other than that, I have no clue what I'm talking about. :D

    I'd definitely be interested in being able to semi-permanently mount a USB connector under my dash to plug in an ALDL cable.
    Familiar with 1227747 and 16197427 PCMs

  14. #14
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    that one LOOKS like it could work. there does seem to be Rx and Tx pins that could be used for the ALDL end, but i'm not 100% certain of it. you would need to tie them together before the ALDL M pin obviously, then assuming there is a ground pin, and that's all the connections necessary.

    i don't know why everybody doesn't just buy them from the link i posted, unless you want a potentially more stable supplier?
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  15. #15
    RIP EagleMark's Avatar
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    Everytime you post that link costs me an hour looking around...

    OK here's the start of OBDII flash, I did my part now someone needs to do the software...
    http://www.sparkfun.com/search/resul...&what=products

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

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