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Subject: Re: ISA IRQ signal active how long?
Date: Wed, 16 Oct 2002 16:14:59 -0400
Organization: Arius, Inc
NNTP-Posting-Date: 16 Oct 2002 20:14:55 GMT
X-Mailer: Mozilla 4.79 [en] (Win95; U)
Meindert Sprang wrote:
> "Noname Nospam" wrote in message
> > The usual driver for for an IRQ line is the 74LS125, Tri-State buffer.
> > The IRQ for the ISA bus are ACTIVE HIGH.
> > The 8259 PIC for DOS and Windows is programmed for LEVEL sensitive mode.
> Is that what it says in the IBM manual you mention below? I have here an
> Intel ISA bus spec which says that 'the interrupt controller will react to
> the interrupt on a transition of low to high'. Futher in this document it
> also says that the interrupts are edge triggered.
> It seems that Intel and IBM are not at the same wavelength here....
Can you provide a link for that spec? Since the IEEE droped their
version of the ISA spec it has been impossible to get one.
Rick "rickman" Collins
Ignore the reply address. To email me use the above address with the XY
Arius - A Signal Processing Solutions Company
Specializing in DSP and FPGA design URL http://www.arius.com
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