>We are using 512K of code memory and 128K of Data memory in our target system
>Have you had a look at the Philips Mx and P89C669, they both address 8Mb without banking and Philips usually have low cost ICEs for their chips.

In response to Eriks comment - Philips have the PDS51E series of emulators that cover the 51mx (PDE51Mx) and 669 (PDE669) device families (the 669 would probably be a better fit for your system). Note that PDS51E data indicates that the emulator only contains 256K of memory. I think that the emulation of code memory will be the limiting factor in your choice of an emulation system.

A general comment about emulating data memory - In your case you wish to emulate the 128K of data memory. There is no reason for this to live in the emulator! It already exists in your target and the emulator should therefore be able to access it. As it is in your target whatever memory banking system you employ will function assuming it meets the basic memory timing requirements of an 8xC51.

Regards,
Graham