Another way to describe the IRQ problem is that there are too many! I
wish we didn't have to hassle with them at all.
But since we do, my solution was to get a bus mouse with lots of
configuration options. Whenever I add a new serial device, I shuffle IRQ
and address settings to get everything coexisting, then add the mouse.
Something to bear in mind with the serial shuffle is what IRQs do:
prioritize. In unbuffered communications, this is an important
consideration. For example, if you had an old-style serial port with a
high-speed modem plugged into it, on COM1 (IRQ4). If your mouse was on
COM2 (IRQ3), it would likely create problems due to higher priority (the
priority sequence for ATs is lower number=higher priority within two
groups: 8-15, 3-7). So if you used the mouse during a modem (or Zoomer
transfer) session, it would take priority and transfer data could be lost
while the mouse was being attended to by the computer. You seem to be
well aware of this, since your setup is the opposite. But I thought it
might be worth tossing this concept into the mix of responses.
--- john@silcom.com - John L. Wiley - Santa Barbara, CA