Yes, and I also know that those switches don't work on all machines; BIOS variations, sensitivity to initial conditions, race conditions, phase of the moon, who knows?
Believe me, isolating the serial data lines was NOT our first choice but it was the only method that worked reliably.
-- Rich Webb Norfolk, VA
That is not an FTDI problem but a windows problem (the infamous Crazy Mouse problem). It also happens when you start W2K and XP while serial data already comes in on *any* serial port. As a matter of fact, you can tweak the INF files of the FTDI driver to prevent this problem by disabling the serial enumerator in windows for that specific port. We do this in our products as well, which makes the USB versions of our NMEA multiplexers work better than the RS-232 versions.
Meindert
Windows outputs a special serial enumeration sequence on the DTR and RTS lines during startup. When you block the RxD line during this activity, Windoze will not interpret incoming data as a mouse. A small PIC of some sort could be programmed to do this.
This is all nicely documented in the "Plug and Play External COM Device Specification" from Microsoft.
Meindert
Yes, and for some dark reason, these options do sometimes work, sometimes they don't.
Meindert
Nice to know that it's there, but no solution if you just have all sorts of serial stuff that may be spitting out data when you boot your PC.
Why can't the serial mouse driver not at least check the incoming data and decide there is no mouse data it can sensibly use? Just invoking random cursor movements on random incoming data doesn't sound like solid design.
-- Stef (remove caps, dashes and .invalid from e-mail address to reply by mail) A budget is just a method of worrying before you spend money, as well as afterward.
Thanks for the info. In that specific application, we already had a "listening watch" on a serial port from the XPe for other status info and were able to use that as the port enable.
Hmm... but use the dance of the DTR & RTS lines to a retriggerable used as a gate disable.
-- Rich Webb Norfolk, VA
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