Hi chiiujen Chung,
As far as my knowledge goes (based on the information you gave here ), I have just one suggestion:

If your CPU is MCS-51 family then shift your design to P89C669, or use the Keil Compiler which supports code banking, I have never used code banking before, but I think it is for the same purpose. Many members will inform you how code banking is done (especially read Erik's posts), or you can go to the Keil website, which gives you information about code banking. Sorry, I do not know the link to this particular page but it is on www.keil.com.

If the CPU is not MCS-51 family, then you have posted on the wrong forum.





Bye,
Mr. Kiran V. Sutar.