APIC 82489 datasheet

Hi all,
Does anyone have a datasheet for APIC 82489 chip? I could not find it
anywhere..
I understand that this chip is a replacement for I8259 used till now as
an interrupt controller on a PC/AT. I would like to learn more, and to play
with extra IRQs (IRQ15+) it provides.
Most modern PC chipsets support this chip am I correct?
Thanks for help.

Janusz

[Maciej W. Rozycki]

On Tue, 18 Nov 2003, Mlodzianowski Janusz wrote:
> Does anyone have a datasheet for APIC 82489 chip? I could not find it
> anywhere..

AFAIK, it has never been published in an electronic form.  Do you really
have such a chip in any equipment? -- it's a ten years old design and it
went out of production quite long ago.  It was used for i486 and some
early/unusual Pentium systems.  Unless you need documentation for this
very APIC implementation (which is a bit different from its derivatives),
appropriate bits are included in other documents that are available at the
Intel web site.
> I understand that this chip is a replacement for I8259 used till now as
> an interrupt controller on a PC/AT. I would like to learn more, and to play
> with extra IRQs (IRQ15+) it provides.

The i82489DX has exactly 16 I/O interrupt entries, so that's not really
that many more beyond what's been available in the i8259A setup as
specified by the PC/AT architecture.  Certain later APIC implementations
(e.g. the i82093AA) have more interrupt entries and they are fairly well
documented on-line.
> Most modern PC chipsets support this chip am I correct?

If you're particularly interested in a PC-specific APIC setup, then you
should consider getting "Multiprocessor Specification" and probably some
ACPI docs as well.

Maciej