Adding dual 16550 (ace) ISA adapter to DPW500au

From: Franz Fischer <Franz.Fischer_at_franz-fischer.de>
Date: Tue, 11 Sep 2001 13:28:54 +0200 (MET DST)

Hello Managers and Tru64 Wizards,

I really don't like that ISA stuff (never owned a PC so far), but I needed
additional serial ports on my DPW500au box running DU4.0D (still, upgrade to
G scheduled for the next weeks). So I went to the shop, got a dual 16c550
ISA board and...

... while configuring jumpers and such, I discovered, that all available ISA
interrupts except for #9 are already used by embedded devices (esp. 10 for
(currently) useless serial bus and #14 plus #15 for EIDE.)

So I setup (in SRM with iconfig) only one of the adapters as COM3, booted
genvmunix, which recognizes the port as ace2, built new kernel --- all works
fine.

Now the question: Is there any way to get the second port to work?

Neither iconfig nor isacfg let me configure some sort of ``interrupt
sharing'', so even if I tweaked the board to OR the two interrupts together
this wont help.

Currently I configured (as separate slot in isacfg) the second port as COM4
w/ appropriate iobase and irq left empty, and genvmunix recognizes ace3, but
of course w/o interrupt using this serial line won't work.

Any hints how to get the second 16c550 to work in a DPW500au?
Can I disable some of the unused embedded devices (however, the hardwired
interrupt line on the MLB/riser card will remain) or can I get both ports on
the same interrupt #9 with the stock ace driver?

(Last resort is kernel patching and get a wrapper aceintr, which handles
unit 2 AND 3 when an interrupt for ace2 is launched... :-))

Thanks in advance for any hints.

Regards

Franz G. Fischer
--
Franz G. Fischer ----------------------------- Franz.Fischer_at_franz-fischer.de
Received on Tue Sep 11 2001 - 11:29:43 NZST

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