ARM Technical Support Knowledge Articles

USING PDATA ON ADUC83X AND ADUC84X DEVICES

Applies to: C51 C Compiler

Answer


Information in this article applies to:


SYMPTOM

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.

RESOLUTION

The following lists how PDATA is accessed for certain devices:

MORE INFORMATION

SEE ALSO

Article last edited on: 2006-10-24 14:16:19

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