I still run and build/modify an old Z80 based CP/M Computer from the 80's and still have fun with it.
I good idea would be to be able to get a readout of the current Memory Address and the 8 bits of Data.
So far I've not used an Aarduino in the port mode! that is reading a full port, just bits! Also I think I would have to say read/connect portA for A7-0, portB for A15-8. Data not sure depends on which Arduino.
But then I would have to add the two 8 bit port values to give me a 16 bit result!! and display it on an LCD that bit I can do. Mostly done robot sort of things.
Any help and advice most welcome, even if I'm heading the wrong way..
You should be more specific. Do you want to run the Arduino together with or instead of the Z80?
The Mega has (parts of) a memory interface for 8 data and 16 bit addresses, that allows to attach old style memory chips. It also has enough unrestricted 8 bit ports for attaching to the Z80 address and data bus in read-only mode.
For the AVR based Arduinos, Atmel (now Microchip) gives C code on page 61 of the datasheet. Each port has a register of pin states that can be referenced as PINx where x is the port letter, just like each pin in that port can be referenced PINxn. PINxn referres to n bit in PINx.
