Sorry for the OT, but I'm hoping there will be some savvy hardware bods out
there who can shed some light.

A colleague of mine has created a VXD for use under Win98. This driver reads
ADC samples at a very high rate, the requirements of the hardware. With no
USB ports on the PC, it runs fine, not losing any samples. But he just
attached a USB port (I've yet to find out if it's a pucker card or some sort
of USB-to-something card to fake USB), enabled USB in the BIOS and now the
driver is dropping samples.

The driver disables interrupts with the CLI instruction - the colleague has
theorised that somehow the USB system (or the PnP system, or both) is using
a non-maskable interrupt. I just opened and closed my mouth at him like a
goldfish, since that is way too hardwarey for me.

Anyone know anything about this?

He found that if he disabled the USB device, the driver coped OK. Is there
any way to switch a device off programmatically, so they could do that while
this program is running using this driver? To compound the pain the code is
written in MSVC1.52, but we could do some sort of thunking to get some
32-bit code to run to switch the device on and off, if necessary.

Any help would be appreciated.

--
Jason Teagle
[EMAIL PROTECTED]



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