IRQ Question (A+)

peterattheboro · 6 Aug 2008 at 10:28

Not sure where to put this as it's to do with the CompTIA A+ qualification which I am currently studying for.

I am reading up on the IRQ section (PITA) and I quote from the book

Here's how cascading controllers work. In Figure 4-5, the path that the math coprocessor (which uses IRQ 10) takes to send an interrupt request to the processor is shown in three steps:

Here's a picture of the diagram shown in the book.

(Yes i'm bored

)

Book is CompTIA A+ For Dummies. (9 in 1)

Must say it's a very good book apart from this 1 bit of confusion. Lucky I know most of it anyway before I got the book

Apologies if this is in the wrong forum

peterattheboro · 6 Aug 2008 at 10:42

Apologies for dull thread, this is probably going to get zero replies (minus this one)

leezer3 · 6 Aug 2008 at 14:02

Typo in the book I'd say.
As far as I'm aware, the math coprocessor should always be on IRQ 13 for a normal machine.
In otherwords-

IRQ13 (Math coprocessor)==Request==> IRQ 9 (Shunts request to IRQ Controller 1)==Request==> Processor on IRQ 2

-Leezer-

peterattheboro · 7 Aug 2008 at 08:48

Yeah that's what I thought. Cheers.

Thanks for saving the pointless thread of the day

(yesterday)