XPAGE VTREG

The µVision Simulator can simulate multiple XDATA banks, but it must be configured for this. When you enable far memory type support in your µVision project, you need to add either the module L51_BANK.A51 or XBANKING.A51 to your project. The XDATA banking method is defined in these files and the simulator needs to be configured to use the same bank register/address to calculate the correct address. By default, XDATA banking is switched off in the µVision simulator. On classic 8051 devices, the XPAGE VTREG allows you to specify the XDATA page to use or the SFR register that contains the XDATA page. For example:

• XPAGE=0xFFFFFFFF: Use default behavior for MOVX @DPTR instructions, which means that the XDATA area is limited to 64K and bank information is ignored. (default)
• XPAGE= value: Values in the range 0x00 - 0xFF are taken as a fixed XDATA bank.
• XPAGE= value: Any other value than 0x00 - 0xFF is taken as address of a SFR register or XDATA address which specifies the XDATA bank number.

Note

• Refer to article µVISION DEBUGGER: SIMULATING BANKED XDATA / FAR MEMORY for further information.