I've been reading this forum a long time and finally started working on my 2600 clone game console since my 2600 died.
If I am reading the schematics right, we have A1-A11 tied to the chips through the cartridge connector and the 8 data lines D1-D8. This should mean we have a 2k mappable ROM space.
However, in looking at the schmatics more, we seem to have 2 Chip Selects. 1 is typically tied down to the Atari CPU and would assume it is used in a standard way to select the ROM chip when addresses A1-A11 are used. This seems to be active low.
Curious is the other CS (EXROM) (also active low), which in all the sample cartridges that I found is tied to VCC,
I am trying to understand a bit more about how we get >2k ROM given the schematics I've seen.