Part-14. Programmable Interrupt Controller

[Hans Cadans]

Hi, everybody.

While designing the Harvard-2, I felt, more and more, the need of handling interrupts.
So I decided to design an interrupt handler.

Easy said, but I think, I did succeed in making such a circuit.
The interrupt controller can handle 8 interrupts, it determines, itself, the priority.

The Harvard-2, uses the opcode 0xAD, to call a subroutine. To call a subroutine, one needs an address to call.
In this sense, the controller is programmable. You can program the controller with the opcode,
with 8 addresses for interrupt service routines and you can change, in a simple way, the priority of the channels.

In the next topic I will modify the Harvard-2, in such a way, that it can work along with this controller.
Of course, I designed this controller, with the properties of the Harvard-2 in mind.

The PIC has not been finished yet. If you have a design of your own, you will, maybe, have to make some modifications or expansions.
You also can wait for my next topic.
Feel free to ask me anything, if something is not quite clear.

At last I wish everyone a Merry Christmas and a Happy New Year.

Hans Cadans