Prolific Serial->USB Adapter

[huafist]

I've got a Prolific adapter, chipset PL-2303. It'll connect without any issues, and I can eventually burn data across it (takes 10+ minutes), but nothing in the dashboard shows any data. I can open a terminal and see some data transferring, but nothing operates. Seems like I read somewhere in the past that you have to copy a file from an older driver install over one from the new one to make it work, but I can't find that now. Any suggestions?

[devastator]

You might try posting this question in the "MS-II and V2.2/V3 Main Board Assembly, Testing, and Troubleshooting section". More computer dudes hang out there.

[huafist]

In that case, I'd rather a mod move it - I deplore cross-posting.

[Mike_Robert]

Wow, if everyone were as considerate and courteous as you we wouldn't need mods. Thank you!
To your question; I have used an adapter based on that chipset for a long time with several different machines and OS's. I've only found it squirrelly once and that was remedied by dropping the buffers to 1 in the Device Manager properties dialog. I don't know what OS you're using but I recently found that the Win7/64 MS supplied driver definitely doesn't work at all but a reference driver from either Prolific or Aten does work without problem.

-Mike

[huafist]

That's strange. At this point, I've tried about 8 different drivers, I've dropped the FIFO buffers to 1, even disabled them entirely at one point. I've found that sometimes if I turn the stim RPM all the way to 0, the gauges will work, but as soon as it starts sending a tach signal, they stop working - as if there's too much data being sent for it to work.

It has me thoroughly confused - can you tell me which driver you have used with success?

[Mike_Robert]

The data packets don't increase in frequency or size when a tach signal is sent. What are you powering the stim with? Which stim is it? Things can get out of shape rapidly with bad power to the stim. Wall warts, small batteries (9v for sure), battery chargers - all can have insufficient or very noisy outputs. I don't recall if the non-JimStims would possibly draw more power with the tach signal increased but I don't think you could even get a zero tach signal from them anyway - you must be using a JimStim. I'm just throwing train of thought stuff out there right now...

Please relate what hardware (computer, adapter mfg), software (TS, MT, MTunix, ?), OS, MS board and firmware versions, etc.

[huafist]

It's a standard stim, not a jimstim. Powered with a 12VDC, 500mA wall wart.
I've tried 3 PC's - two Dell latitude D830 laptops running XP Pro SP3, and a Fujitsu tablet PC running win2k SP4 (this is the machine I'm using in the car). The MS is MSII, PCB v3.0, ms2extra 2.1.0p codebase.

This behavior is with TS. MT does nothing but freeze.

[devastator]

I'm using a Fujitsu tablet PC running win2k SP4 in my vehicle to tune with too, but my USB to Serial adapter came from Radio Shack, and works fine. Do you know anyone with a MS installation you could test your cable on to verify that it isn't the stim?

[Mike_Robert]

I wonder if the various vendors who repackage/resell the Prolific chipset manufacture the entire device differently. I hate to say this but it seems like your USB/serial adapter just isn't going to work - it's happened before. Can you try someone else's or buy one from DIYAutoTune? It certainly sounds like you've addressed most variables except for the adapter. It's very odd that you can occasionally get working serial comms with no RPM. One last thought - do you have the stim and the laptop plugged into different AC outlets? I recall someone having a reproducible "no comm" situation which was tracked down to the two being connected to different legs/ground potentials of the house AC current. I'm pretty sure if the laptop is running off battery only this wouldn't be a concern. Also, what devastator said!

-Mike

[huafist]

I'm the only one in the area that builds/tunes Megasquirt systems as far as I know. I know one other guy that had one and sold it.

Yeah, they were both plugged into the same outlet. To test, I even hooked it up in the car and ran the laptop off of the battery. Still nothing. But it works perfectly fine with the serial cable. Dunno, it's a POS adapter.

[devastator]

Dunno, it's a POS adapter.

Sounds like it.

[Mike_Robert]

And there you go.

[huafist]

Picked up another adapter the other day, same chipset, different brand. Works fine.

Go figure haha.