Hi Matthew,

this is a difficult question, since I can not give out the complete answer.
On reading, with some logic you can set A16 high on using /RD or low on using PSEN.
On writing you have several ways, e.g. use the Dallas ROM size feature to execute from internal code space and switch A16 with a port pin. Please look on the Dallas application notes.
I use another way.

Its the best to put all the logic into a PLD/CPLD. This can also do the address decoding for other peripherals (memory mapped IO).


I run into the same problem, since the Dallas 80C320 is to fast for using Flash. So I use fast SRAM and copy the code from Flash to SRAM after reset.


Peter