Can i use port 0 as data/address bus (it is bidirectional but only one tolks at a time)

Sure, the problem you will have is that a high on the bus will be delayed by the time constant of your pullup resistor and the capacitance of the bus, which, with 32 nodes, can be quite a bit.

Speaking generally, let us take a port 0 that can pull low 1mA. Let us take that each node (chip and wiring) is 25 pF. with 32 nodes your capacitance will be 800 pF. The smallest pullup you can use will be 5k for 1mA.

so 5k * 800p = 4us, which gives you a marginal bus speed of 250KHz (you will have to go lower), and that is with the values above that may very well be optimistic.

Another problem with open collector buses is that they are very noise suspectible and you will have to take that into account (make sure the bus is stable before the clock arrives) which makes your throughput even less.

Erik

I suggest you try hard to fing a supplier of SILabs or Philips or another brand with configurable ports.

PS whare are you in the world?