Code Banking Example

A code banking application with the following memory map:

Memory Area	Address Range	Usage
On-Chip RAM	I:0x00–I:0xFF	Registers, bits, variables, stack, ...
External RAM	X:0x0000–X:0x7FFF	Variables too large for on-chip RAM.
ROM	C:0x0000–C:0x7FFF (common area)	Program code and constants.
CODE ROM	C:0x000000–C:0x03FFFF (code banks)	Program code and constants.

requires the following linker command line:

LX51 BANK0 {A.OBJ},
     BANK1 {B.OBJ},
     BANK2 {C.OBJ},
     BANK3 {D.OBJ}
     BANKAREA (0x8000-0xFFFF)
     CLASSES (
             XDATA  (X:0x0000-X:0x7FFF),
             HCONST (C:0x000000-C:0x03FFFF)
             CODE   (C:0x0000-C:0xFFFF)
             )

There are several Application Notes available that show how to create programs for extended 8051 devices.