[Coco] How does the cartridge port work, anyway?

[Allen Huffman]

On Feb 15, 2013, at 7:09 AM, John Donaldson <johnadonaldson at sbcglobal.net> wrote:
> Allen,
>    I'm surprised at you. It is really simple. The Cart connector has a pin that 
> is connected to the NMI (Non Maskable Interrupt) of the 6809 CPU. This interrupt 
> is tripped by the Cart's when the COCO is powered up. The software routine 
> associated withe the NMI then calls Address C0000 and executes the instructions 
> starting at that address. Thus the Cart program then runs.

I are a software guy :) The most complex hardware I ever did was soldering wires for making RS232 connectors or such.

I am specifically interested in learning to interface hardware to that port, specifically a Teensy or Arduino device. I am seeing how easy it is on modern hardware, and wonder if it would be easier or harder going back to much simpler stuff.

		-- Allen