Bus activity on internal register access of 2A03

Bus activity on internal register access of 2A03
by on (#49085)
Does the external address and data bus show access to internal registers on the 2A03?

ie, if the 2A03 was writing or reading from $4000 to $4018 would you see that activity on the external bus.

by on (#49095)
I was thinking address $4016 more specifically and it seems my answer may be yes.

by on (#49097)
$4016 and $4017 aren't really internal registers -- you're addressing external hardware (a 74hc368).

by on (#49099)
The audio registers also address "external hardware": the audio mixer. But the CPU has separate output pins for strobe, port 1 clock, and port 2 clock, so it wouldn't have to put $4016 or $4017 on the address bus for some chip to decode. Nor does it have to put the OAM page number written to $4014 or the frequency written to $400A and $400B on the data bus. But given how the 6502 likes to operate (all memory access, all the time), it would probably have cost more gates not to drive the buses.