(First post! Woo-hooo!!)
I have a question about the 2A03's bus signals: Do these always behave the same way for internal register accesses as they do for external accesses? For e.g.: Does writing something to $4000 cause that something to appear on D[7:0], $4000 to appear on A[15:0], R/W to go low? Brad Taylor's vintage 2A03 Technical Reference states, "Reads from $4016 and $4017 are decoded inside the 2A03, and those signals are available externally." I'm guessing the whole truth is simpler and more general than this, but it doesn't appear to be discussed at all in the more-recent Wiki treatment. (Although I've been known to miss things. Often.)
I have a question about the 2A03's bus signals: Do these always behave the same way for internal register accesses as they do for external accesses? For e.g.: Does writing something to $4000 cause that something to appear on D[7:0], $4000 to appear on A[15:0], R/W to go low? Brad Taylor's vintage 2A03 Technical Reference states, "Reads from $4016 and $4017 are decoded inside the 2A03, and those signals are available externally." I'm guessing the whole truth is simpler and more general than this, but it doesn't appear to be discussed at all in the more-recent Wiki treatment. (Although I've been known to miss things. Often.)