🚀 go-pugleaf

Richard Slobod <71231.104@compuserve.com> wrote in message
<3779c2c0.67039642@news.warwick.net>...
>haeb@haeb.noc.easynet.net (Harry Broomhall) wrote:
>>In article <rO9ACAAphHe3EwAI@dunvegan1.demon.co.uk>,
>> Paul Richards <Paul@dunvegan1.demon.co.uk> writes:
>
>>> and 1 LPT port (takes an IRQ?).
>>
>>  Depends. If in standard mode then it doesn't need one.  In ECP mode
>>it will try and grab one.
>
>While it's not usually used, even an old unidirectional (non-EPP,
>non-ECP) parallel port gets assigned an IRQ (although Win9x seems
>quite willing to ignore this and let you set it up in the Device
>Manager without the IRQ assignment).
>
>>>  How many IRQ's do PC's have?
>>
>>   In theory - 16. Some are predefined by the PC, so rather fewer than
>>that are available for plug-in cards.
>
>Actually, it's only 15 even before you start taking the preassigned
>ones into account because IRQs 2 and 9 are one and the same.
Well There are actually 16, it is just the IRQ2, is disconnected from the
'outside world', and used as the 'cascade' to generate the other eight. On
most of the modern chipsets, it doesn't even come out of the chip, but
functionally you can still program it, but you just receive an interrupt,
when any of the interrupts occur from the second controller. It is distinct
from 9, but 9 is the IRQ, that gets connected to the wire it used to have.
It is a bit of a 'pedant' thing, but just because it is not available,
doesn't make it 'not exist' :-)

Best Wishes