Uber-easy DIY USB ALDL Cable

[shimniok]

Remember me from 2 years ago? :D I'm back to messing with DIY ALDL setup on my 7747, wanted to share updates. Hope it's not old news. Using Sparkfun FTDI Basic Breakout 5V with an emitter-follower transistor as a signal buffer. For whatever reason I could not get a data stream when it was running unless I had the buffer. So far so good, except some data errors after waking the laptop and starting the Jeep. I'll dig into that and do more testing this week as I fine tune the Jeep for emissions using my own Ostrich 2.0 and Burn2 (was using AutoProm in 2012).

When I'm convinced I have it working reliably I'll design a small board for myself with FTDI chip, USB connector, transistor(s), filtering caps, whatever else. I could make extras if anyone is interested. I don't have anything to test the 8192 stuff on, but could try to build it to accommodate that too.

[joegreen]

is thier a cheap simple ft232rl that i can use with my 1227747 ecu that ships from the us instead of from china with their crazy shipping times?

[RobertISaar]

i believe you can set ebay to remove all results outside of a chosen area. beyond that, not much else, almost everything is china based.

[joegreen]

I believe this should work? http://pages.ebay.com/link/?nav=item...363471&alt=web

[shimniok]

Just a quick update. I have not yet resolved the problems with the Sparkfun FT232RL but I'm still working on it. I'll let you know what I come up with.

What happens is that the USB adapter appears to stop receiving data. I'm not sure if this is a problem with the FT232RL or the host computer or what, exactly. I do know that the RX light on the device stops blinking, but that can be caused by a variety of things. I'll have to take an oscilloscope along next time and investigate after the problem occurs, I guess.

Unplugging the device from USB and reinserting it, disconnecting and reconnecting does seem to work most of the time. I've updated the drivers to the 2/2014 version to no avail.

I somewhat suspect a ground problem or some electrical noise/interference/overvoltage or something along those lines. The adapter is getting power from the USB device. The signal is coming in from the ECM. The USB adapter is grounded to the ECM box. I should probably explore how that's grounded.

[RobertISaar]

I believe this should work? http://pages.ebay.com/link/?nav=item...363471&alt=web

looks fine.

Just a quick update. I have not yet resolved the problems with the Sparkfun FT232RL but I'm still working on it. I'll let you know what I come up with.

What happens is that the USB adapter appears to stop receiving data. I'm not sure if this is a problem with the FT232RL or the host computer or what, exactly. I do know that the RX light on the device stops blinking, but that can be caused by a variety of things. I'll have to take an oscilloscope along next time and investigate after the problem occurs, I guess.

Unplugging the device from USB and reinserting it, disconnecting and reconnecting does seem to work most of the time. I've updated the drivers to the 2/2014 version to no avail.

I somewhat suspect a ground problem or some electrical noise/interference/overvoltage or something along those lines. The adapter is getting power from the USB device. The signal is coming in from the ECM. The USB adapter is grounded to the ECM box. I should probably explore how that's grounded.

no other laptop to test with to rule that out? the ECM side of datalogging is pretty solid on a 7747, so i would assume adapter or laptop.

[steveo]

i just chopped out my aldl port and replaced with one of these

I love it. . even has blinky lights! I love blinky lights

thanks for the tip Robert

[RobertISaar]

i'm considering doing the same for all of my cars..... cost ~$4(and any enclosure you might use) and just hide the USB cable somewhere, save the ALDL cable some wear and tear for the vehicles that don't have a cable integrated into it.

i've only come across 1 application that has issues so far: 88-93 grand prixs with a DIC. the drive circuit in them seems to be just weak enough to where even just having the cable hooked up will cause it to quit receiving ALDL data. have to either unplug the cable or have a toggle switch open the circuit for when you don't need to datalog. i've seen this with 3 different cars and don't know what to think of it. other DIC/DIS systems of the era don't seem to have an issue with a cable just being present.

[joegreen]

ok so i received my ft232rl today and soldered up one wire to the tx and rx and another wire to the ground. i cannot get the cable to work with winaldl or tunerpro rt. i tried doing cable tests and they all failed. I believe this is what it should look like. the tx and rx lights light up when i first put it into the computer. i looked around online and made sure the com port was correct and that is was set to 4800 baud which i read was 160 baud. Dont mind my somewhat archaic solder job. I had some crappy solder because i could not find my spool of the good stuff.