As can be seen, this is a very simple circuit at this point, 1 IC, a series of pull up resistors, and a jumper to bypass the IRQ logic chip.
The circuit was originally fairly complex with between 6 and 8 IC chips. When I was laying out the PCB, I found it was taking up too much realestate, and on top of it, with the way everything was connected, it was becoming extremely difficult to keep traces separated with only 2 layers for signal - even though I was doing a 4 layer board, the inner two layers were setup for power and ground.
The chip itself, utilizing some primitives from Altera and the MAX II+ Baseline software, I layed out the circuit and burned it into the chip, the section below talks more about the chip itself. Although I am not a VHDL programmer, the MAX software allows for graphical editing which does make life much easier.
IRQ Logic
Here is the logic that is in the MAX 7000s series chip I used. The chip is a 44 pin PLD in a PLCC case. It is one of Altera's smaller IC's, but it is more then sufficient for my needs. I do appologize that the picture is a bit hard to see, the full size of the graphic is just too big and I couldn't get a screenshot big enough to capture it in large text.
But, with some observation, you can see how this is a fairly simple design. A set of 74148 megafunctions (came with the software), and a few AND gates, NOT gates, and some output enable controls it is very easy to design a complex circuit into a single chip. This is all reproduceable as VHDL, but as I don't know VHDL, the use of gates and interconnections work quite well for me. I found the use of this sofware a wonderful way to get my programmable arrays without having to spend a lot of time learning a new language.
I will learn VHDL some day, but I also needed to get this project going, and that would have held me up, especially considering what this and the other custom chip I created needed to do.