Port Conflict

It appears that you have some very weird stuff happening. Get another PC and try it again. It is not uncommon for the drivers of various devices to confuse each other.

Next time:

1) Read ALL of the instructions. Sometimes USB devices need to be plugged in after a certain point in the install

2) Disable your virus protection. sometimes Norton will prevent certain parts of drivers from beiong correctly installed

3) Ditch the USB adapter and get a PCMCIA adapter like the ones written about here.


Originally posted 2 Jan 2002 by Fred Patton

Keep in mind that laptops have a lot of kludgy hardware work-arounds to save space and power. The 80x86 design is kludgy to begin with, and with laptops the shortcomings of the basic Wintel PC design are exacerbated. Many of the more aggravating kludges involve video, but serial comms can get nasty as well.

Serial ports in the 80x86 design use what's known as cascading interrupts, which means a master, usually IRQ 2, actually serves as a conduit (so to speak) for an additional 8 interrupts (the slave). This can mean any interrupt above 7 can potentially interfere with IRQ2. If your motherboard is poorly engineered, IRQ2 can even
interfere with IRQ3, which are usually the two interrupts used for serial comms. USB further complicates matters, because for the 12-18 months or so of its existence, the USB spec had gray areas in it and some of the USB hardware on the market was buggy, even with normally well-engineered brands such as IBM and Compaq.

Imagine a wall outlet (AC power) with 8 plugs. Then some bonehead comes along and plugs a power strip with 8 additional outlets into plug #2. That's the basic idea behind cascading interrupts, and it's rife with problems.

In general, problems of this nature usually cause interference between COM1 and COM3, and between COM2 and COM4. What I would suggest is as follows:

1. Uninstall your USB serial device drivers.

2. Disable the device currently occupying COM2, which will be either your modem or your infrared port.

3. Re-install your USB serial driver, which will hopefully grab COM2, leaving you with timer data IN on COM1 and GAZ data OUT on COM2.

If you can get your two devices working as COM1 and COM2, or COM3 and COM4, that will eliminate the problem of a cascade-induced disruption.

The Fred's suggestion to use a serial comm PCMCIA card rather than USB is also a very good one. I'm not a big fan of USB in general, especially under some of the more unstable flavors of Windows such as 95, 98 and Millenium. Under Win2000, USB seems a bit more solid. USB is not supported under NT.


Originally posted 3 Jan 2002 by James Broder
james@skunkware.tv

Hey Guys -

Thanks for the lesson interrupt lesson - I must be closing in, huh?

I gave up on the USB in order to eliminate variables. I have a Socket I/O card, but I'm still having the same problem. I managed to configure my timer as com3 and my scoreboard as com4. I can get my scoreboard to work in either port, but only when the timer's not plugged in. I can get my timer to work in either port and it
ignores whether the scoreboard is plugged in or not. (But the scoreboard won't work because the timer's plugged in!) I have a feeling I'm short an interrupt, but I can't find a way to disable the infrared interrupt - I can't even find one.

This run-around happens with two different laptops that both run 98 - a dell and a toshiba. I haven't tried Chase's suggestion, but I'll get back to you.


Originally posted 6 Jan 2002 by Margaret Brady

Please let us know if you have an event coming up in the near future. We have several notebooks that are all set up and work available for emergencies. Just send us a Fedex or UPS account number to bill and we will loan you a notebook for the weekend all set up with a dual serial card.

Originally posted by Fred Patton