Serial Elanscan Lead and Serial to USB Convertor

[Gary]

Help !

I have a serial Elanscan lead which I want to plug into a USB port on my laptop. I have a USB to serial convertor. However the convertor needs drivers. When I load these drivers, I never get the chance to load the drivers for the Elanscan lead, and keep getting a 'no data' message.

How can I load the Elanscan drivers ?

Has anyone else got this sort of setup working ?

[ailwyn]

Erm... once you load the drivers for the USB to Serial and that works you shouldn't need any other drivers.

How computer literate are you?

[Gary]

I won't answer that question.

However, I get the 'no data' message. The solution to that is to change the latency to 1. The drivers for the usb/serial do not allow this option....Is there a way I can change it from the command line ?

[ESM]

The trouble with USB, where using it to work with old serial is concerned, is that its designed to move very large volumes of data at a very high rate. The design of the system involves large buffers (not the same as the serial ones you set up in the serial port driver) that are emptied in bursts of high speed comms. The data volume from ALDL is tiny by the standards of USB and so is the rate. So the data goes into the USB buffer and isn't released to actually go to the RS232 comm port for some time. This causes problems for ElanScan because it adds timestamps and compares checksums as it goes. So if the data hasn't appeared by the time ElanScan is due to ask for the next data packet it shrugs and gives up (showing the error). This is compounded by the fact that when ES does get the data it gets the answer to about 400 queries all at once and/or the ECU gets about 800 queries at once.

So most USB -> serial converters do not work with ElanScan (or other ALDL programs for that matter). However, one USB->serial chip manufacturer put a clever feature in the driver that gets round the problem. In converters that use the FTDI chip you can set the driver to empty the USB buffer (i.e. send the data to the serial port) after each millisecond of inactivity - this is the latency setting - and that pretty much solves the problem.

So in short not all USB -> Serial interfaces will work in this application. It has to be one with an FTDI chip in it. They sell converters themselves here.

[GeoffSmith]

I've already offered Gary the proven solution but he decided to go with the cheap option.

[Sy V]

[Gary]

Thanks for the thorough reply ESM. So I need the £12.50 lead then and a large donation to the LEC kitty for everyone's help....

[Sy V]

That's about the size of it, Gary. As the actress said to the bishop...

[Gary]

I've had a (money saving) thought !

Could I not just remove the serial plug and replace it with a USB plug (if I knew the correct wiring) ?

Or have I missed something ?

[al]

Could I not just remove the serial plug and replace it with a USB plug (if I knew the correct wiring) ?

Or have I missed something ?

Please don't do that, or at least if you do, please post the pictures of the aftermath up here once you're done blowing stuff up.

[Gary]

I take it that means it won't work then?

[GeoffSmith]

You never know, it might ......... and you'll have saved yourself £20.57.



Pulls up chair, sits back and waits for firework display to start.

[Gary]

Why though ? Surely it is just a serial port either old 'serial' or new Universal 'Serial' Bus ?

[Paul.P]

You never know, it might ......... and you'll have saved yourself £20.57.

They say " look after the pennies, & the million's look after themselves ", & i reckon Gary's on his 3rd !

[ESM]

Here's a money saving thought... Why not take the engine out of a horse and cart and put it in a car? Then you wouldn't need to buy petrol. You could just park it in a field.

[Gary]

I've noticed a couple of these leads on EBAY - I'm waiting to take the plunge !

I'm assuming as long as it is a SERIAL->USB with an FTDI chip I should be ok ?

[ailwyn]

Something tells me you've received about as much help as you can expect on this, so by all means bid away.

[dapinky]

In case Ailwyns reply was a bit confusing, i believe what he actually would have liked to write (if he wern't a respected Moderator) is something like this.......


(I ain't a Mod, so I can get away with it)


"For F**ks Sake, Gary, how many times do you need to be told! You can buy whatever you want, for as little money as you want to spnd, but much of the cr@p out there wont work properly.
The only way we know it will work is to buy the tried and trusted kit off the old ex-geordie git (Or ESM if he has any), and then you're home and dry.

Anything else MIGHT work, or might cause your lappy to explode, but i don't care as long as you ain't next to me when it goes bang.

Get yer wallet out, and beg Geoff to have a suitable bit of kit with him at the weekend.

Yours truly,

Ailwyn"


Now i might be wrong, and MAYBE that isn't what he meant at all...............

[GeoffSmith]

[Gary]

I prefer the DaPinky version !

So Mr Smith have you got anything that can help me ?