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From: mitchell@MDI.COM (Bill Mitchell)
Newsgroups: comp.os.msdos.programmer
Subject: Re: interrupt numbers for com3 and com4?
Message-ID: <1991Jun23.133904.28000@MDI.COM>
Date: 23 Jun 91 13:39:04 GMT
References: <1991Jun22.205821.21533@msuinfo.cl.msu.edu>
Sender: news@MDI.COM
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In article <1991Jun22.205821.21533@msuinfo.cl.msu.edu> leeda@frith.egr.msu.edu (Dae Hee Lee) writes:
>
>com1 and com2 are assigned int12h and int 11h (irq4 and irq3), respectively.
>Then how about com3 and com4?
>Could you help me?

Some info I have handy indicates that COM1 and COM3 normally share
IRQ4 and INT0C, while COM2 and COM4 share IRQ3 and INT0B.  It is
up to the ISR to figure out which port is interrupting by testing the
hardware.

-- 
mitchell@mdi.com (Bill Mitchell)