Yeah I'm familiar with reading the memory mapped io, but the 8080 cpu does it differently, its not a memory address, its an actual CPU command. Using Asteroids as an example, instead of the game code reading 0x2400-0x2404 for the switch inputs, it would just say "IN1" and get back an instant 8 bit answer. Thats what I finally understand, but I was trying to figure out how to perform that command from the Fluke, which only does basic memory read/writes like that Asteroids memory map. (In fact I also may write a nice Asteroids script to test all that stuff too).
For example, one use of this, is if I'm testing a sound on an SI board. Sure I have the test rom but that tests each sound one at a time then resets the board. If I already have the Fluke plugged in, I can have it display a menu of sounds, then choose to play one once or have it loop that sound for troubleshooting. Easy to do with Asteroids, just write to 3c04 for a sound, but with this I have to emulate the game code saying "OUT5".
However, I read something last night that didn't sink in until I was driving to work today....simply have the fluke write the command to ram, say at 0x2000, tell the board to execute starting at 0x2000, have the command send the results (if any) to a different part of ram (like 0x2100), then have the fluke read it back. A little kludgy but it would work! I could even mod the test rom to talk to the Fluke - that would be cool! In fact that would be awesome considering all the sound and memory testing programs are already in the test rom. Damn why didn't I think of that yesterday?!?!
The only downside to the idea of the Fluke writing cpu commands to ram, is if the ram is bad, you're screwed anyway lol. This is ESPECIALLY true on Midway 8080 boards.
Oh and FYI - incase anyone ever messes with the 8080 pod and writes 9010A scripts for one, You MUST include the pod file with the script (include 8080.c), and have "enable ready" and "enable hold" in the setup section or none of your scripts will work and you will curse, cry, pout, and take your pod apart trying to figure out why the Fluke stops working when you try to run a script. Just ya know, saying.