Now, I don't know much about these devices, having looked at them when they first came out, but the data sheet seems, clearly, to say that the chip has on it the same memory as a normal 8032. Additional memory is available if you use the PSD Module to which they refer on page 133 of the datasheet. This module offers numerous interesting features, and your desired memory expansion seems to be among them.

The datasheet,

http://www.st.com/stonline/...d3354d.pdf ,

says, about

External Direct Addressing
This mode will access external memory (XDATA)
by using the 16-bit address stored in the DPTR
Register.

and about

External Indirect Addressing
This mode will access external memory (XDATA)
by using the 8-bit address stored in either Register
R0 or R1. This is the fastest way to access XDATA
(least bus cycles), but because only 8-bits are
available for address, this mode limits XDATA to a
size of only 256 bytes (the traditional Port 2 of the
8032 MCU is not available in the uPSD33xx, so it
is not possible to write the upper address byte).
This mode is not supported by uPSD33xx.

Naturally they'd like you to buy that, since it will "lock you in" to using their series of parts. There are devices from other manufacturers that have on-chip data memory outside the "normal" range of 256 bytes provided in the classic 8052 model. Unless this device family conveniently addresses some requirement that you have, e.g. the analog components, etc, perhaps products offered by SiLabs, some of which also have analog resources, or Maxim/Dallas, for the dual data pointers, and additional on-chip RAM, or whatever, both of which offer MUCH faster parts, might better suit your requirements.

I'm not sure what you mean by pData if it's not within the 256-byte range that can be addressed by the generic 805x. Since the address fields in 805x instructions are limited to 8 bits (aside form AJMP and ACALL), and the registers with which you address internal memory indirectly are only 8 bits, it suggests that external memory (xRAM) is your only "normal" option. If all you want is to avoid the effort of adding a latch and the external SRAM, you can't do that with this device anyway, as it lacks the P2 port through which the high address byte is normally provided. It does seem, with the 80-pin part, to have the ability to produce external addresses, but in some way probably not supported by the "conventional" 'C' compiler.

RE