Final part of the logic plus ROM:

Here you can see how I do address bits manipulation for ROM to have memory models described earlier - now total count of integrated circuits is 22 (plus #PDPii CPU module and #PDPii RAM module). As I said before RAM module will have its own slightly modified BBQ-slot - instead of A15 it will have always "1" and custom BSYNC signal will be used to mask RAM in places where it's not supposed to be located. Also XOR chip IC21 will be used to mix ROM pages (just to be able to boot from any of them).