abstract.txt

Keil uVision2

*** IMPORTANT NOTE ***
    Far Memory Support is only available in the PK51 package.
    If you have an CA51, DK51, or Evaluation Package the far memory
    support is not available and this example will not work.


The ADuC812 16MB RAM DEMO program shows you how to use the new
features of C51 Version 6.12 and LX51 Linker/Locater Version 3.10
to access the large 16MB xdata space on this device.

C51 provides you with the 'far' memory type that can be used to
access large memory.  The memory accesses itself is performed in
the XBANKING.A51 configuration file.  The example includes a configured
version of the XBANKING.A51 file that accesses the large 16M Byte external 
address space via the extended DPP register of the ADuC812 device.

The 'far' memory type is handled at linker level via the memory class HDATA.
You can enter the address range in uVision2 under Options for Target -
LX51 Locate - User Classes as shown below: 
   HDATA (X:0x020000-X:0x02FFFF) /* put 'far' into X:0x20000 - X:0x2FFFF */

The large memory space is simulated under uVision2 with the X: memory type prefix.
For example the uVision2 debugger command:
   >D X:0x20000                   // displays external data starting at 0x20000