Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!gatech!prism!jgb
From: jgb@prism.gatech.EDU (James G. Baker)
Newsgroups: comp.os.msdos.programmer
Subject: Re: PC Uarts & Interrupts
Message-ID: <30559@hydra.gatech.EDU>
Date: 4 Jun 91 13:56:38 GMT
References: <1991May30.015340.27879@netcom.COM>
Organization: Georgia Institute of Technology
Lines: 26

In article <1991May30.015340.27879@netcom.COM> resnicks@netcom.COM (Steve Resnick) writes:
>
>I have a bunch of interrupt driven serial code I wrote, which inits the
>port, sets up interrupts and handlers, then queus all incoming and outgoing
>data ... So far so good, except that I get one interrupt. I am doing an EOI
>by sending 20H to port 20H, and OUT2 is asserted to enable 8250 interrupts.
>My interrupt enable value is 3, and my mask value to the 8250 is 0xEA.

Getting only one interrupt sounds like the EOI is not being sent correctly.
You say your interrupt enable value is 3 = ? = irq3?  Keep in mind that
on an AT, if you use irq2 it is actually irq9 (transparent) except that two
EOI must be sent.

If it is irq3, could there be anything else using irq3?  Can you switch
it to something else like irq5 (AT)?

Good luck.

-J Baker


-- 
BAKER,JAMES G - Undergraduate Lab Instructor, School of Electrical Engineering
____  _    _    Georgia Institute of Technology, Atlanta Georgia, 30332
  |  | _  |_)   uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!jgb 
(_|. |_). |_).  Internet: jgb@prism.gatech.edu, jgb@ee, jgb@eecom, jgb@cc