|ARM Technical Support Knowledge Articles|
Applies to: C51 C Compiler
Information in this article applies to:
PDATA is a 256-byte area of XDATA memory that is accessed using the MOVX @R0 and MOVX @R1 instructions.
On 8051 devices which externally address XDATA (XDATA is off-chip), the value of the P2 SFR is used as the upper address byte (R0 or R1 contain the lower address byte).
On devices with on-chip XDATA memory, P2 may be used for I/O and not as the upper address byte. Such cases require special settings for the PDATA configuration in the startup code and in the uVision Simulator.
The following lists how PDATA is accessed for certain devices:
Article last edited on: 2006-10-24 14:16:19
Did you find this article helpful? Yes No
How can we improve this article?