Using AST 4port or clone on uPort

[Otto J. Makela]

In article <701 at tukki.jyu.fi>, makela at tukki.jyu.fi (Otto J. Makela) says:
>I recently got a (supposedly accurate) clone of a AST 4port card. [...]
>The uPort manual says to use for example
>	ttypatch -t6 -i7 -a416 -n4 -v0x1bf -m0
>and to take care that the card is in the enhanced (enchanted ?)
>mode and that "shared interrupts are disabled (SW 3-3)".
>The enhanced mode is easy, the opposite is that the card is COM1,
>COM2 and two non-standard ports.  But I'm not sure about the
>shared interrupt stuff (disturbingly, the card I have has only one
>DIP switch) ?
>[...] (the machine has both COM1 and COM2 on the mother board).
[plus what happened, how it didn't work...]

I now know why it does not work.  The small print on the release document
states that IRQ's cannot be shared by different cards.  When I disabled
the motherboard COM2 and used IRQ3, all worked ok.  The big question now
is, how does one define "different cards" ?

I have a card which has 8 RS-232 ports.  All these ports are identical with
the basic PC RS ports.  This 8fold monster can be configured to be COM1, COM2,
COM3, COM4 + 4 nonstandard ports, or as 8 nonstandard ports with a few
variations.  Each port can be set to produce IRQ3 or IRQ4.  I guess they are
logically on "different cards", since they are totally independent ?

The question about shared interrupts still stands.  What do the card settings
have to do with the interrupt mechanism ?

Otto J. Makela (with poetic license to kill), University of Jyvaskyla

InterNet: makela at tukki.jyu.fi, BitNet: MAKELA_OTTO_ at FINJYU.BITNET
BBS: +358 41 211 562 (V.22bis/V.22/V.21, 24h/d), Phone: +358 41 613 847
Mail: Kauppakatu 1 B 18, SF-40100 Jyvaskyla, Finland, EUROPE