Date: Thu, 6 Apr 1995 11:43:15 +0200
From: fs5a019 AT rrz DOT uni-hamburg DOT de (Carsten Benecke)
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Results: Interrupt Programming


Hi,

some days ago I wrote to this group to get help for my INTERRUPT PROGRAMMING
problem. 
I want to thank Roland Exler and Mr. Long. Your hint solved my problem !!.

For all those who have the same problems I would like to summerise the whole
solution:

If your hardware rises an IRQ in the range IRQ 8-15 make sure:

1. your interrupt service function should acknowledge the hardware. The 
   interrupt line should not be aktivated any longer...
2. acknowledge the second (slave) PIC at base 0xa0 first (outportb (0xa0,0x20))
3. acknowledge the first (master) PIC at base 0x20 (outportb (0x20,0x20)) 


If the hardware which rises the IRQ does not release the IRQ the PICs do
not accept(!) the acknowledge.

Cheers, Carsten Benecke.