I'm using uPSD3234A40 (52pin TQFP) for my ckt. This chip does not have P0, P2, PA ports. I would like to implement data and address bus using the PLD logic. Is it possible? The current board is with 8032 and PSD813 with address and data bus used to map display. Can I use the same firmware with the new board with uPSD3234A40-T6?
I don't understand. The P0 and P2 ports _are_ the address and data bus pins. You can't use them as general purpose I/O ports if you are going to use external memory access. Since your part (the 52-pin version) doesn't present the external bus on pins at all, then how is an external PLD going to help? Are you thinking of manually driving a bus access cycle using I/O ports? That's certainly going to require firmware changes. Can you design your new board with the 80-pin part instead, and just hook up the external bus as normal? I'd expect the firmware to require little (if any) change at that point; if needed, it'd probably be in the area of the startup configuration.
I have a current board with 80C32 and PSD813 with memory mapped I/Os like RAM, LCD etc. LCD has the data bus connected to it. What I want is to replace the MCU and PSD devices with a single uPSD IC WITHOUT CHANGING THE FIRMWARE. In the uPSD3234A-40 data sheet on page 127, Figure 63, its mentioned that the data bus can be copied to a port. How can that be done? Also refer to Figure 64 ans Table 92.