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From: np4@prism.gatech.EDU (POMPONIO,NICHOLAS A)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: QUESTION ABOUT INTERRUPT REQUEST 7
Message-ID: <26167@hydra.gatech.EDU>
Date: 12 Apr 91 19:36:38 GMT
References: <TRUX.91Apr7085133@atop.atop.cs.caltech>
Distribution: comp
Organization: Georgia Institute of Technology
Lines: 18

trux@atop.atop.cs.caltech (Flem Snopes) writes:

>I want to use the acknowledge line on my paralell port to trigger interrupt
>0Fh.  I enable IRQ7 on the 8259 PIC, then I hook interrupt 0Fh.  When I bring
>ACK low, the interrupt happens but when I bring ACK low again (after it going
>high for some time) the interrupt is not triggered.  Is there some flag I need
>to set to let the 8259 Programmable Interrupt Controller know I am ready to
>deal with the next -ACK signal?  Thanks.
>-trux

Try issuing a "non-specific EOI" by writing 20H to I/O port 20H. This is
generally done within the interrupt service routine.

-- 
POMPONIO,NICHOLAS A
Georgia Institute of Technology, Atlanta Georgia, 30332
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