After re-reading the txt a few additional thoughts....
The CE for the data line 245 must be an undefined (in the information presented) outboard connection to the host, probably an expansion window enable line of some sort.
This appears to present a n Kbyte block into the memory map of the host, via an expansion window. That said, not absolute addressing, no zero page conflicts.
I didnt see an example shown of using Arduino IDE to load the memory array, or mention of where. Comments show the 7FFF mask references the PCjr's memory not the Teensy's.
I have never used it but have seen examples of how to load an array into the Arduino family's memory via the IDE. That method wont work for our goal.
Running full tilt like it does assures data will alway be present, but it's not likely to win any power consevation awards...lol
