Hi Roberto,

You can not access external RAM with CE0-3, only with PCE0-3.
How you would like to access the external program (the MUX pin state) ?
What are the values of AM1 and AM0 bits in the ACON SFR ?
Do you have in mind to use it at full 40Mhz speed ?

Sorry to tell you that, but if you have problems now trying
to connect external peripherals, I can imagine how it will be
when you will manufacture the pcb.

I'm sure that someone will advice you to search the forum.

Best regards,
Silviu